Address code review feedback

Streaming save and memory reduction

.envrc

@@ -0,0 +1 @@
+use flake

.gitattributes

@@ -1 +1 @@
-gui-src/** linguist-vendored
+src/gui/** linguist-vendored

.github/ISSUE_TEMPLATE/bug_report.md

@@ -11,13 +11,13 @@ assignees: ''
 A clear and concise description of what the bug is and what you expected to happen.
 
 **Used bbox area**
-Please provide your input parameters so we can reproduce the issue. *(For example: 48.133444 11.569462 48.142609 11.584740)*
+Please provide your input parameters (BBOX) so we can reproduce the issue. *(For example: 48.133444 11.569462 48.142609 11.584740)*
 
 **Arnis and Minecraft version**
-Please tell us what version of Arnis and Minecraft you used.
+Please tell us what version of Arnis and Minecraft you used, as well as if you are on Windows, Linux or MacOS.
 
 **Screenshots**
 If applicable, add screenshots to help explain your problem.
 
 **Additional context**
-Add any other context about the problem here. If you used any more custom settings, please provide them here too. If you experienced any issue with the application itself like a crash, please provide the log file which can be found at C:\Users\USERNAME\AppData\Local\com.louisdev.arnis\logs
+Add any other context about the problem here. If you used any more custom settings, please provide them here too. Please provide the log file if possible as well, which can be found at C:\Users\USERNAME\AppData\Local\com.louisdev.arnis\logs

.github/workflows/ci-build.yml

@@ -18,13 +18,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout code
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Set up Rust
       uses: dtolnay/rust-toolchain@v1
       with:
         toolchain: stable
-        components: clippy
+        components: clippy, rustfmt
 
     - name: Install Linux dependencies
       run: |
@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout code
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Set up Rust
       uses: dtolnay/rust-toolchain@v1

.github/workflows/pr-benchmark.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up Rust
         uses: dtolnay/rust-toolchain@v1
@@ -43,7 +43,7 @@ jobs:
       - name: Run benchmark command with memory tracking
         id: benchmark
         run: |
-          /usr/bin/time -v ./target/release/arnis --path="./world" --terrain --bbox="48.101470,11.517792,48.168375,11.626968" 2> benchmark_log.txt
+          /usr/bin/time -v ./target/release/arnis --path="./world" --terrain --bbox="48.125768 11.552296 48.148565 11.593838" 2> benchmark_log.txt
           grep "Maximum resident set size" benchmark_log.txt | awk '{print $6}' > peak_mem_kb.txt
           peak_kb=$(cat peak_mem_kb.txt)
           peak_mb=$((peak_kb / 1024))
@@ -65,7 +65,7 @@ jobs:
           seconds=$((duration % 60))
           peak_mem=${{ steps.benchmark.outputs.peak_memory }}
 
-          baseline_time=135
+          baseline_time=30
           diff=$((duration - baseline_time))
           abs_diff=${diff#-}
 
@@ -79,7 +79,7 @@ jobs:
             verdict="🚨 This PR **drastically worsens generation time**."
           fi
 
-          baseline_mem=5865
+          baseline_mem=935
           mem_annotation=""
           if [ "$peak_mem" -gt 2000 ]; then
             mem_diff=$((peak_mem - baseline_mem))
@@ -87,6 +87,8 @@ jobs:
             mem_annotation=" (↗ ${mem_percent}% more)"
           fi
 
+          benchmark_time=$(date -u "+%Y-%m-%d %H:%M:%S UTC")
+
           {
             echo "summary<<EOF"
             echo "⏱️ Benchmark run finished in **${minutes}m ${seconds}s**"
@@ -98,6 +100,8 @@ jobs:
             echo ""
             echo "${verdict}"
             echo ""
+            echo "📅 **Last benchmark:** ${benchmark_time}"
+            echo ""
             echo "_You can retrigger the benchmark by commenting \`retrigger-benchmark\`._"
             echo "EOF"
           } >> "$GITHUB_OUTPUT"
@@ -108,4 +112,4 @@ jobs:
           message: ${{ steps.comment_body.outputs.summary }}
           comment-tag: benchmark-report
         env:
-          GITHUB_TOKEN: ${{ secrets.BENCHMARK_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.BENCHMARK_TOKEN }}

.github/workflows/release.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Set up Rust
       uses: dtolnay/rust-toolchain@v1
@@ -87,7 +87,7 @@ jobs:
       shell: powershell
 
     - name: Upload artifact
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       with:
         name: ${{ matrix.os }}-${{ matrix.target }}-build
         path: target/release/${{ matrix.asset_name }}
@@ -97,13 +97,13 @@ jobs:
     runs-on: macos-latest
     steps:
     - name: Download macOS Intel build
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v7
       with:
         name: macos-13-x86_64-apple-darwin-build
         path: ./intel
 
     - name: Download macOS ARM64 build
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v7
       with:
         name: macos-latest-aarch64-apple-darwin-build
         path: ./arm64
@@ -114,7 +114,7 @@ jobs:
         chmod +x arnis-mac-universal
 
     - name: Upload universal binary
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       with:
         name: macos-universal-build
         path: arnis-mac-universal
@@ -124,22 +124,22 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout code
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Download Windows build artifact
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v7
       with:
         name: windows-latest-x86_64-pc-windows-msvc-build
         path: ./builds/windows
 
     - name: Download Linux build artifact
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v7
       with:
         name: ubuntu-latest-x86_64-unknown-linux-gnu-build
         path: ./builds/linux
 
     - name: Download macOS universal build artifact
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v7
       with:
         name: macos-universal-build
         path: ./builds/macos

.gitignore

@@ -1,8 +1,8 @@
 /wiki
+*.mcworld
 
 # Environment files
 .env
-.envrc
 /.direnv
 
 # Build artifacts

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "arnis"
-version = "2.3.0"
+version = "2.4.0"
 edition = "2021"
 description = "Arnis - Generate real life cities in Minecraft"
 homepage = "https://github.com/louis-e/arnis"
@@ -14,40 +14,49 @@ overflow-checks = true
 
 [features]
 default = ["gui"]
-gui = ["tauri", "tauri-plugin-log", "tauri-plugin-shell", "tokio", "rfd", "dirs", "tauri-build"]
+gui = ["tauri", "tauri-plugin-log", "tauri-plugin-shell", "tokio", "rfd", "dirs", "tauri-build", "bedrock"]
+bedrock = ["bedrockrs_level", "bedrockrs_shared", "nbtx", "zip", "byteorder", "vek"]
 
 [build-dependencies]
 tauri-build = {version = "2", optional = true}
 
 [dependencies]
+base64 = "0.22.1"
+byteorder = { version = "1.5", optional = true }
 clap = { version = "4.5", features = ["derive", "env"] }
 colored = "3.0.0"
 dirs = {version = "6.0.0", optional = true }
-fastanvil = "0.31.0"
-fastnbt = "2.5.0"
+fastanvil = "0.32.0"
+fastnbt = "2.6.0"
 flate2 = "1.1"
 fnv = "1.0.7"
 fs2 = "0.4"
-geo = "0.30.0"
+geo = "0.31.0"
 image = "0.25"
 indicatif = "0.17.11"
 itertools = "0.14.0"
 log = "0.4.27"
 once_cell = "1.21.3"
 rand = "0.8.5"
+rand_chacha = "0.3"
 rayon = "1.10.0"
 reqwest = { version = "0.12.15", features = ["blocking", "json"] }
-rfd = { version = "0.15.4", optional = true }
-semver = "1.0.23"
+rfd = { version = "0.16.0", optional = true }
+semver = "1.0.27"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 tauri = { version = "2", optional = true }
 tauri-plugin-log = { version = "2.6.0", optional = true }
 tauri-plugin-shell = { version = "2", optional = true }
-tokio = { version = "1.47.0", features = ["full"], optional = true }
+tokio = { version = "1.48.0", features = ["full"], optional = true }
+bedrockrs_level = { git = "https://github.com/bedrock-crustaceans/bedrock-rs", package = "bedrockrs_level", optional = true }
+bedrockrs_shared = { git = "https://github.com/bedrock-crustaceans/bedrock-rs", package = "bedrockrs_shared", optional = true }
+nbtx = { git = "https://github.com/bedrock-crustaceans/nbtx", optional = true }
+vek = { version = "0.17", optional = true }
+zip = { version = "0.6", default-features = false, features = ["deflate"], optional = true }
 
 [target.'cfg(windows)'.dependencies]
 windows = { version = "0.61.1", features = ["Win32_System_Console"] }
 
 [dev-dependencies]
-tempfile = "3.20.0"
+tempfile = "3.23.0"

README.md

@@ -1,17 +1,17 @@
-<img src="https://github.com/louis-e/arnis/blob/main/gitassets/banner.png?raw=true" width="100%" alt="Banner">
+<img src="assets/git/banner.png" width="100%" alt="Banner">
 
 # Arnis [![CI Build Status](https://github.com/louis-e/arnis/actions/workflows/ci-build.yml/badge.svg)](https://github.com/louis-e/arnis/actions) [<img alt="GitHub Release" src="https://img.shields.io/github/v/release/louis-e/arnis" />](https://github.com/louis-e/arnis/releases) [<img alt="GitHub Downloads (all assets, all releases" src="https://img.shields.io/github/downloads/louis-e/arnis/total" />](https://github.com/louis-e/arnis/releases) [![Download here](https://img.shields.io/badge/Download-here-green)](https://github.com/louis-e/arnis/releases) [![Discord](https://img.shields.io/discord/1326192999738249267?label=Discord&color=%237289da)](https://discord.gg/mA2g69Fhxq)
 
-Arnis creates complex and accurate Minecraft Java Edition worlds that reflect real-world geography, topography, and architecture.
+Arnis creates complex and accurate Minecraft Java Edition (1.17+) and Bedrock Edition worlds that reflect real-world geography, topography, and architecture.
 
 This free and open source project is designed to handle large-scale geographic data from the real world and generate detailed Minecraft worlds. The algorithm processes geospatial data from OpenStreetMap as well as elevation data to create an accurate Minecraft representation of terrain and architecture.
 Generate your hometown, big cities, and natural landscapes with ease!
 
-![Minecraft Preview](https://raw.githubusercontent.com/louis-e/arnis/refs/heads/main/gitassets/preview.jpg)
-<i>This Github page is the official project website. Do not download Arnis from any other website.</i>
+![Minecraft Preview](assets/git/preview.jpg)
+<i>This Github page and [arnismc.com](https://arnismc.com) are the only official project websites. Do not download Arnis from any other website.</i>
 
 ## :keyboard: Usage
-<img width="60%" src="https://github.com/louis-e/arnis/blob/main/gitassets/gui.png?raw=true"><br>
+<img width="60%" src="assets/git/gui.png"><br>
 Download the [latest release](https://github.com/louis-e/arnis/releases/) or [compile](#trophy-open-source) the project on your own.
 
 Choose your area on the map using the rectangle tool and select your Minecraft world - then simply click on <i>Start Generation</i>!
@@ -19,7 +19,7 @@ Additionally, you can customize various generation settings, such as world scale
 
 ## 📚 Documentation
 
-<img src="https://github.com/louis-e/arnis/blob/main/gitassets/documentation.png?raw=true" width="100%" alt="Banner">
+<img src="assets/git/documentation.png" width="100%" alt="Banner">
 
 Full documentation is available in the [GitHub Wiki](https://github.com/louis-e/arnis/wiki/), covering topics such as technical explanations, FAQs, contribution guidelines and roadmaps.
 
@@ -34,7 +34,7 @@ Full documentation is available in the [GitHub Wiki](https://github.com/louis-e/
 #### How to contribute
 This project is open source and welcomes contributions from everyone! Whether you're interested in fixing bugs, improving performance, adding new features, or enhancing documentation, your input is valuable. Simply fork the repository, make your changes, and submit a pull request. Please respect the above mentioned key objectives. Contributions of all levels are appreciated, and your efforts help improve this tool for everyone.
 
-Command line Build: ```cargo run --no-default-features -- --terrain --path="C:/YOUR_PATH/.minecraft/saves/worldname" --bbox="min_lng,min_lat,max_lng,max_lat"```<br>
+Command line Build: ```cargo run --no-default-features -- --terrain --path="C:/YOUR_PATH/.minecraft/saves/worldname" --bbox="min_lat,min_lng,max_lat,max_lng"```<br>
 GUI Build: ```cargo run```<br>
 
 After your pull request was merged, I will take care of regularly creating update releases which will include your changes.
@@ -51,7 +51,7 @@ After your pull request was merged, I will take care of regularly creating updat
 
 ## :newspaper: Academic & Press Recognition
 
-<img src="https://github.com/louis-e/arnis/blob/main/gitassets/recognition.png?raw=true" width="100%" alt="Banner">
+<img src="assets/git/recognition.png" width="100%" alt="Banner">
 
 Arnis has been recognized in various academic and press publications after gaining a lot of attention in December 2024.
 
@@ -78,7 +78,7 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.[^3]
 
-Download Arnis only from the official source (https://github.com/louis-e/arnis/). Every other website providing a download and claiming to be affiliated with the project is unofficial and may be malicious.
+Download Arnis only from the official source https://arnismc.com or https://github.com/louis-e/arnis/. Every other website providing a download and claiming to be affiliated with the project is unofficial and may be malicious.
 
 The logo was made by @nxfx21.
 

flake.lock

@@ -0,0 +1,60 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1755615617,
+        "narHash": "sha256-HMwfAJBdrr8wXAkbGhtcby1zGFvs+StOp19xNsbqdOg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "20075955deac2583bb12f07151c2df830ef346b4",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-unstable",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,36 @@
+{
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    {
+      flake-utils,
+      nixpkgs,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+
+        stdenv = if pkgs.stdenv.isLinux then pkgs.stdenvAdapters.useMoldLinker pkgs.stdenv else pkgs.stdenv;
+      in
+      {
+        devShell = pkgs.mkShell.override { inherit stdenv; } {
+          buildInputs = with pkgs; [
+            openssl.dev
+            pkg-config
+            wayland
+            glib
+            gdk-pixbuf
+            pango
+            gtk3
+            libsoup_3.dev
+            webkitgtk_4_1.dev
+          ];
+        };
+      }
+    );
+}

flake/flake.lock

@@ -1,99 +0,0 @@
-{
-  "nodes": {
-    "fenix": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "rust-analyzer-src": "rust-analyzer-src"
-      },
-      "locked": {
-        "lastModified": 1724653830,
-        "narHash": "sha256-88f0KK8h6tGIP4Na5RJDKs0S+7WsGGaCGNkLj/bPV3g=",
-        "owner": "nix-community",
-        "repo": "fenix",
-        "rev": "9ecf5e7d800ace001320da8acadd4a3deb872a83",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "fenix",
-        "type": "github"
-      }
-    },
-    "flake-utils": {
-      "inputs": {
-        "systems": "systems"
-      },
-      "locked": {
-        "lastModified": 1710146030,
-        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "nixpkgs": {
-      "locked": {
-        "lastModified": 1724479785,
-        "narHash": "sha256-pP3Azj5d6M5nmG68Fu4JqZmdGt4S4vqI5f8te+E/FTw=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "d0e1602ddde669d5beb01aec49d71a51937ed7be",
-        "type": "github"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "ref": "nixos-unstable",
-        "type": "indirect"
-      }
-    },
-    "root": {
-      "inputs": {
-        "fenix": "fenix",
-        "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
-      }
-    },
-    "rust-analyzer-src": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1724586512,
-        "narHash": "sha256-mrfwk6nO8N2WtCq3sB2zhd2QN1HMKzeSESzOA6lSsQg=",
-        "owner": "rust-lang",
-        "repo": "rust-analyzer",
-        "rev": "7106cd3be50b2a43c1d9f2787bf22d4369c2b25b",
-        "type": "github"
-      },
-      "original": {
-        "owner": "rust-lang",
-        "ref": "nightly",
-        "repo": "rust-analyzer",
-        "type": "github"
-      }
-    },
-    "systems": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
-      }
-    }
-  },
-  "root": "root",
-  "version": 7
-}

flake/flake.nix

@@ -1,34 +0,0 @@
-{
-  inputs = {
-    fenix = {
-      url = "github:nix-community/fenix";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
-    flake-utils.url = "github:numtide/flake-utils";
-    nixpkgs.url = "nixpkgs/nixos-unstable";
-  };
-
-  outputs = { self, fenix, flake-utils, nixpkgs }:
-    flake-utils.lib.eachDefaultSystem (system:
-      let
-        pkgs = nixpkgs.legacyPackages.${system};
-        fenixPkgs = (fenix.packages.${system}.stable);
-      in
-      {
-        devShell = pkgs.mkShell
-          {
-            buildInputs = with pkgs; [
-              openssl.dev
-              pkg-config
-              fenixPkgs.toolchain
-              wayland
-              glib
-              gdk-pixbuf
-              pango
-              gtk3
-              libsoup_3.dev
-              webkitgtk_4_1.dev
-            ];
-          };
-      });
-}

src/args.rs

@@ -1,6 +1,6 @@
 use crate::coordinate_system::geographic::LLBBox;
 use clap::Parser;
-use std::path::Path;
+use std::path::PathBuf;
 use std::time::Duration;
 
 /// Command-line arguments parser
@@ -21,7 +21,7 @@ pub struct Args {
 
     /// Path to the Minecraft world (required)
     #[arg(long, value_parser = validate_minecraft_world_path)]
-    pub path: String,
+    pub path: PathBuf,
 
     /// Downloader method (requests/curl/wget) (optional)
     #[arg(long, default_value = "requests")]
@@ -64,8 +64,8 @@ pub struct Args {
     pub spawn_point: Option<(f64, f64)>,
 }
 
-fn validate_minecraft_world_path(path: &str) -> Result<String, String> {
-    let mc_world_path = Path::new(path);
+fn validate_minecraft_world_path(path: &str) -> Result<PathBuf, String> {
+    let mc_world_path = PathBuf::from(path);
     if !mc_world_path.exists() {
         return Err(format!("Path does not exist: {path}"));
     }
@@ -76,7 +76,7 @@ fn validate_minecraft_world_path(path: &str) -> Result<String, String> {
     if !region.is_dir() {
         return Err(format!("No Minecraft world found at {region:?}"));
     }
-    Ok(path.to_string())
+    Ok(mc_world_path)
 }
 
 fn parse_duration(arg: &str) -> Result<std::time::Duration, std::num::ParseIntError> {

src/bedrock_block_map.rs

@@ -0,0 +1,849 @@
+//! Bedrock Block Mapping
+//!
+//! This module provides translation between the internal Block representation
+//! and Bedrock Edition block format. Bedrock uses string identifiers with
+//! state properties that differ slightly from Java Edition.
+
+use crate::block_definitions::Block;
+use std::collections::HashMap;
+
+/// Represents a Bedrock block with its identifier and state properties.
+#[derive(Debug, Clone)]
+pub struct BedrockBlock {
+    /// The Bedrock block identifier (e.g., "minecraft:stone")
+    pub name: String,
+    /// Block state properties as key-value pairs
+    pub states: HashMap<String, BedrockBlockStateValue>,
+}
+
+/// Bedrock block state values can be strings, booleans, or integers.
+#[derive(Debug, Clone)]
+pub enum BedrockBlockStateValue {
+    String(String),
+    Bool(bool),
+    Int(i32),
+}
+
+impl BedrockBlock {
+    /// Creates a simple block with no state properties.
+    pub fn simple(name: &str) -> Self {
+        Self {
+            name: format!("minecraft:{name}"),
+            states: HashMap::new(),
+        }
+    }
+
+    /// Creates a block with state properties.
+    pub fn with_states(name: &str, states: Vec<(&str, BedrockBlockStateValue)>) -> Self {
+        let mut state_map = HashMap::new();
+        for (key, value) in states {
+            state_map.insert(key.to_string(), value);
+        }
+        Self {
+            name: format!("minecraft:{name}"),
+            states: state_map,
+        }
+    }
+}
+
+/// Converts an internal Block to a BedrockBlock representation.
+///
+/// This function handles the mapping between Java Edition block names/properties
+/// and their Bedrock Edition equivalents. Many blocks are identical, but some
+/// require translation of property names or values.
+pub fn to_bedrock_block(block: Block) -> BedrockBlock {
+    let java_name = block.name();
+
+    // Most blocks have the same name in both editions
+    // Handle special cases first, then fall back to direct mapping
+    match java_name {
+        // Grass block is just "grass_block" in both editions
+        "grass_block" => BedrockBlock::simple("grass_block"),
+
+        // Short grass is just "short_grass" in Java but "tallgrass" in Bedrock
+        "short_grass" => BedrockBlock::with_states(
+            "tallgrass",
+            vec![(
+                "tall_grass_type",
+                BedrockBlockStateValue::String("tall".to_string()),
+            )],
+        ),
+
+        // Tall grass needs height state
+        "tall_grass" => BedrockBlock::with_states(
+            "double_plant",
+            vec![(
+                "double_plant_type",
+                BedrockBlockStateValue::String("grass".to_string()),
+            )],
+        ),
+
+        // Oak leaves with persistence
+        "oak_leaves" => BedrockBlock::with_states(
+            "leaves",
+            vec![
+                (
+                    "old_leaf_type",
+                    BedrockBlockStateValue::String("oak".to_string()),
+                ),
+                ("persistent_bit", BedrockBlockStateValue::Bool(true)),
+            ],
+        ),
+
+        // Birch leaves with persistence
+        "birch_leaves" => BedrockBlock::with_states(
+            "leaves",
+            vec![
+                (
+                    "old_leaf_type",
+                    BedrockBlockStateValue::String("birch".to_string()),
+                ),
+                ("persistent_bit", BedrockBlockStateValue::Bool(true)),
+            ],
+        ),
+
+        // Oak log with axis (default up_down)
+        "oak_log" => BedrockBlock::with_states(
+            "oak_log",
+            vec![(
+                "pillar_axis",
+                BedrockBlockStateValue::String("y".to_string()),
+            )],
+        ),
+
+        // Birch log with axis
+        "birch_log" => BedrockBlock::with_states(
+            "birch_log",
+            vec![(
+                "pillar_axis",
+                BedrockBlockStateValue::String("y".to_string()),
+            )],
+        ),
+
+        // Spruce log with axis
+        "spruce_log" => BedrockBlock::with_states(
+            "spruce_log",
+            vec![(
+                "pillar_axis",
+                BedrockBlockStateValue::String("y".to_string()),
+            )],
+        ),
+
+        // Stone slab (bottom half by default)
+        "stone_slab" => BedrockBlock::with_states(
+            "stone_block_slab",
+            vec![
+                (
+                    "stone_slab_type",
+                    BedrockBlockStateValue::String("smooth_stone".to_string()),
+                ),
+                ("top_slot_bit", BedrockBlockStateValue::Bool(false)),
+            ],
+        ),
+
+        // Stone brick slab
+        "stone_brick_slab" => BedrockBlock::with_states(
+            "stone_block_slab",
+            vec![
+                (
+                    "stone_slab_type",
+                    BedrockBlockStateValue::String("stone_brick".to_string()),
+                ),
+                ("top_slot_bit", BedrockBlockStateValue::Bool(false)),
+            ],
+        ),
+
+        // Oak slab
+        "oak_slab" => BedrockBlock::with_states(
+            "wooden_slab",
+            vec![
+                (
+                    "wood_type",
+                    BedrockBlockStateValue::String("oak".to_string()),
+                ),
+                ("top_slot_bit", BedrockBlockStateValue::Bool(false)),
+            ],
+        ),
+
+        // Water (flowing by default)
+        "water" => BedrockBlock::with_states(
+            "water",
+            vec![("liquid_depth", BedrockBlockStateValue::Int(0))],
+        ),
+
+        // Rail with shape state
+        "rail" => BedrockBlock::with_states(
+            "rail",
+            vec![("rail_direction", BedrockBlockStateValue::Int(0))],
+        ),
+
+        // Farmland with moisture
+        "farmland" => BedrockBlock::with_states(
+            "farmland",
+            vec![("moisturized_amount", BedrockBlockStateValue::Int(7))],
+        ),
+
+        // Snow layer
+        "snow" => BedrockBlock::with_states(
+            "snow_layer",
+            vec![("height", BedrockBlockStateValue::Int(0))],
+        ),
+
+        // Cobblestone wall
+        "cobblestone_wall" => BedrockBlock::with_states(
+            "cobblestone_wall",
+            vec![(
+                "wall_block_type",
+                BedrockBlockStateValue::String("cobblestone".to_string()),
+            )],
+        ),
+
+        // Andesite wall
+        "andesite_wall" => BedrockBlock::with_states(
+            "cobblestone_wall",
+            vec![(
+                "wall_block_type",
+                BedrockBlockStateValue::String("andesite".to_string()),
+            )],
+        ),
+
+        // Stone brick wall
+        "stone_brick_wall" => BedrockBlock::with_states(
+            "cobblestone_wall",
+            vec![(
+                "wall_block_type",
+                BedrockBlockStateValue::String("stone_brick".to_string()),
+            )],
+        ),
+
+        // Flowers - poppy is just "red_flower" in Bedrock
+        "poppy" => BedrockBlock::with_states(
+            "red_flower",
+            vec![(
+                "flower_type",
+                BedrockBlockStateValue::String("poppy".to_string()),
+            )],
+        ),
+
+        // Dandelion is "yellow_flower" in Bedrock
+        "dandelion" => BedrockBlock::simple("yellow_flower"),
+
+        // Blue orchid
+        "blue_orchid" => BedrockBlock::with_states(
+            "red_flower",
+            vec![(
+                "flower_type",
+                BedrockBlockStateValue::String("orchid".to_string()),
+            )],
+        ),
+
+        // Azure bluet
+        "azure_bluet" => BedrockBlock::with_states(
+            "red_flower",
+            vec![(
+                "flower_type",
+                BedrockBlockStateValue::String("houstonia".to_string()),
+            )],
+        ),
+
+        // Concrete colors (Bedrock uses a single block with color state)
+        "white_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("white".to_string()))],
+        ),
+        "black_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("black".to_string()))],
+        ),
+        "gray_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("gray".to_string()))],
+        ),
+        "light_gray_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("silver".to_string()),
+            )],
+        ),
+        "light_blue_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("light_blue".to_string()),
+            )],
+        ),
+        "cyan_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("cyan".to_string()))],
+        ),
+        "blue_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("blue".to_string()))],
+        ),
+        "purple_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("purple".to_string()),
+            )],
+        ),
+        "magenta_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("magenta".to_string()),
+            )],
+        ),
+        "red_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("red".to_string()))],
+        ),
+        "orange_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("orange".to_string()),
+            )],
+        ),
+        "yellow_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("yellow".to_string()),
+            )],
+        ),
+        "lime_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("lime".to_string()))],
+        ),
+        "brown_concrete" => BedrockBlock::with_states(
+            "concrete",
+            vec![("color", BedrockBlockStateValue::String("brown".to_string()))],
+        ),
+
+        // Terracotta colors
+        "white_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("white".to_string()))],
+        ),
+        "orange_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("orange".to_string()),
+            )],
+        ),
+        "yellow_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("yellow".to_string()),
+            )],
+        ),
+        "light_blue_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("light_blue".to_string()),
+            )],
+        ),
+        "blue_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("blue".to_string()))],
+        ),
+        "gray_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("gray".to_string()))],
+        ),
+        "green_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("green".to_string()))],
+        ),
+        "red_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("red".to_string()))],
+        ),
+        "brown_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("brown".to_string()))],
+        ),
+        "black_terracotta" => BedrockBlock::with_states(
+            "stained_hardened_clay",
+            vec![("color", BedrockBlockStateValue::String("black".to_string()))],
+        ),
+        // Plain terracotta
+        "terracotta" => BedrockBlock::simple("hardened_clay"),
+
+        // Wool colors
+        "white_wool" => BedrockBlock::with_states(
+            "wool",
+            vec![("color", BedrockBlockStateValue::String("white".to_string()))],
+        ),
+        "red_wool" => BedrockBlock::with_states(
+            "wool",
+            vec![("color", BedrockBlockStateValue::String("red".to_string()))],
+        ),
+        "green_wool" => BedrockBlock::with_states(
+            "wool",
+            vec![("color", BedrockBlockStateValue::String("green".to_string()))],
+        ),
+        "brown_wool" => BedrockBlock::with_states(
+            "wool",
+            vec![("color", BedrockBlockStateValue::String("brown".to_string()))],
+        ),
+        "cyan_wool" => BedrockBlock::with_states(
+            "wool",
+            vec![("color", BedrockBlockStateValue::String("cyan".to_string()))],
+        ),
+        "yellow_wool" => BedrockBlock::with_states(
+            "wool",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("yellow".to_string()),
+            )],
+        ),
+
+        // Carpets
+        "white_carpet" => BedrockBlock::with_states(
+            "carpet",
+            vec![("color", BedrockBlockStateValue::String("white".to_string()))],
+        ),
+        "red_carpet" => BedrockBlock::with_states(
+            "carpet",
+            vec![("color", BedrockBlockStateValue::String("red".to_string()))],
+        ),
+
+        // Stained glass
+        "white_stained_glass" => BedrockBlock::with_states(
+            "stained_glass",
+            vec![("color", BedrockBlockStateValue::String("white".to_string()))],
+        ),
+        "gray_stained_glass" => BedrockBlock::with_states(
+            "stained_glass",
+            vec![("color", BedrockBlockStateValue::String("gray".to_string()))],
+        ),
+        "light_gray_stained_glass" => BedrockBlock::with_states(
+            "stained_glass",
+            vec![(
+                "color",
+                BedrockBlockStateValue::String("silver".to_string()),
+            )],
+        ),
+        "brown_stained_glass" => BedrockBlock::with_states(
+            "stained_glass",
+            vec![("color", BedrockBlockStateValue::String("brown".to_string()))],
+        ),
+
+        // Planks - Bedrock uses single "planks" block with wood_type state
+        "oak_planks" => BedrockBlock::with_states(
+            "planks",
+            vec![(
+                "wood_type",
+                BedrockBlockStateValue::String("oak".to_string()),
+            )],
+        ),
+        "spruce_planks" => BedrockBlock::with_states(
+            "planks",
+            vec![(
+                "wood_type",
+                BedrockBlockStateValue::String("spruce".to_string()),
+            )],
+        ),
+        "birch_planks" => BedrockBlock::with_states(
+            "planks",
+            vec![(
+                "wood_type",
+                BedrockBlockStateValue::String("birch".to_string()),
+            )],
+        ),
+        "jungle_planks" => BedrockBlock::with_states(
+            "planks",
+            vec![(
+                "wood_type",
+                BedrockBlockStateValue::String("jungle".to_string()),
+            )],
+        ),
+        "acacia_planks" => BedrockBlock::with_states(
+            "planks",
+            vec![(
+                "wood_type",
+                BedrockBlockStateValue::String("acacia".to_string()),
+            )],
+        ),
+        "dark_oak_planks" => BedrockBlock::with_states(
+            "planks",
+            vec![(
+                "wood_type",
+                BedrockBlockStateValue::String("dark_oak".to_string()),
+            )],
+        ),
+        "crimson_planks" => BedrockBlock::simple("crimson_planks"),
+        "warped_planks" => BedrockBlock::simple("warped_planks"),
+
+        // Stone variants
+        "stone" => BedrockBlock::simple("stone"),
+        "granite" => BedrockBlock::with_states(
+            "stone",
+            vec![(
+                "stone_type",
+                BedrockBlockStateValue::String("granite".to_string()),
+            )],
+        ),
+        "polished_granite" => BedrockBlock::with_states(
+            "stone",
+            vec![(
+                "stone_type",
+                BedrockBlockStateValue::String("granite_smooth".to_string()),
+            )],
+        ),
+        "diorite" => BedrockBlock::with_states(
+            "stone",
+            vec![(
+                "stone_type",
+                BedrockBlockStateValue::String("diorite".to_string()),
+            )],
+        ),
+        "polished_diorite" => BedrockBlock::with_states(
+            "stone",
+            vec![(
+                "stone_type",
+                BedrockBlockStateValue::String("diorite_smooth".to_string()),
+            )],
+        ),
+        "andesite" => BedrockBlock::with_states(
+            "stone",
+            vec![(
+                "stone_type",
+                BedrockBlockStateValue::String("andesite".to_string()),
+            )],
+        ),
+        "polished_andesite" => BedrockBlock::with_states(
+            "stone",
+            vec![(
+                "stone_type",
+                BedrockBlockStateValue::String("andesite_smooth".to_string()),
+            )],
+        ),
+
+        // Blocks with different names in Bedrock
+        "bricks" => BedrockBlock::simple("brick_block"),
+        "end_stone_bricks" => BedrockBlock::simple("end_bricks"),
+        "nether_bricks" => BedrockBlock::simple("nether_brick"),
+        "red_nether_bricks" => BedrockBlock::simple("red_nether_brick"),
+        "snow_block" => BedrockBlock::simple("snow"),
+        "dirt_path" => BedrockBlock::simple("grass_path"),
+        "dead_bush" => BedrockBlock::simple("deadbush"),
+        "note_block" => BedrockBlock::simple("noteblock"),
+
+        // Oak items mapped to dark_oak in Bedrock (or generic equivalents)
+        "oak_pressure_plate" => BedrockBlock::simple("wooden_pressure_plate"),
+        "oak_door" => BedrockBlock::simple("wooden_door"),
+        "oak_trapdoor" => BedrockBlock::simple("trapdoor"),
+
+        // Bed (Bedrock uses single "bed" block with color state)
+        "red_bed" => BedrockBlock::with_states(
+            "bed",
+            vec![("color", BedrockBlockStateValue::String("red".to_string()))],
+        ),
+
+        // Default: use the same name (works for many blocks)
+        // Log unmapped blocks to help identify missing mappings
+        _ => BedrockBlock::simple(java_name),
+    }
+}
+
+/// Converts an internal Block with optional Java properties to a BedrockBlock.
+///
+/// This function extends `to_bedrock_block` by also handling block-specific properties
+/// like stair facing/shape, slab type, etc. Java property names and values are converted
+/// to their Bedrock equivalents.
+pub fn to_bedrock_block_with_properties(
+    block: Block,
+    java_properties: Option<&fastnbt::Value>,
+) -> BedrockBlock {
+    let java_name = block.name();
+
+    // Extract Java properties as a map if present
+    let props_map = java_properties.and_then(|v| {
+        if let fastnbt::Value::Compound(map) = v {
+            Some(map)
+        } else {
+            None
+        }
+    });
+
+    // Handle stairs with facing/shape properties
+    if java_name.ends_with("_stairs") {
+        return convert_stairs(java_name, props_map);
+    }
+
+    // Handle slabs with type property (top/bottom/double)
+    if java_name.ends_with("_slab") {
+        return convert_slab(java_name, props_map);
+    }
+
+    // Handle logs with axis property
+    if java_name.ends_with("_log") || java_name.ends_with("_wood") {
+        return convert_log(java_name, props_map);
+    }
+
+    // Fall back to basic conversion without properties
+    to_bedrock_block(block)
+}
+
+/// Convert Java stair block to Bedrock format with proper orientation.
+fn convert_stairs(
+    java_name: &str,
+    props: Option<&std::collections::HashMap<String, fastnbt::Value>>,
+) -> BedrockBlock {
+    // Map Java stair names to Bedrock equivalents
+    let bedrock_name = match java_name {
+        "end_stone_brick_stairs" => "end_brick_stairs",
+        _ => java_name, // Most stairs have the same name
+    };
+
+    let mut states = HashMap::new();
+
+    // Convert facing: Java uses "north/south/east/west", Bedrock uses "weirdo_direction" (0-3)
+    // Bedrock: 0=east, 1=west, 2=south, 3=north
+    if let Some(props) = props {
+        if let Some(fastnbt::Value::String(facing)) = props.get("facing") {
+            let direction = match facing.as_str() {
+                "east" => 0,
+                "west" => 1,
+                "south" => 2,
+                "north" => 3,
+                _ => 0,
+            };
+            states.insert(
+                "weirdo_direction".to_string(),
+                BedrockBlockStateValue::Int(direction),
+            );
+        }
+
+        // Convert half: Java uses "top/bottom", Bedrock uses "upside_down_bit"
+        if let Some(fastnbt::Value::String(half)) = props.get("half") {
+            let upside_down = half == "top";
+            states.insert(
+                "upside_down_bit".to_string(),
+                BedrockBlockStateValue::Bool(upside_down),
+            );
+        }
+    }
+
+    // If no properties were set, use defaults
+    if states.is_empty() {
+        states.insert(
+            "weirdo_direction".to_string(),
+            BedrockBlockStateValue::Int(0),
+        );
+        states.insert(
+            "upside_down_bit".to_string(),
+            BedrockBlockStateValue::Bool(false),
+        );
+    }
+
+    BedrockBlock {
+        name: format!("minecraft:{bedrock_name}"),
+        states,
+    }
+}
+
+/// Convert Java slab block to Bedrock format with proper type.
+fn convert_slab(
+    java_name: &str,
+    props: Option<&std::collections::HashMap<String, fastnbt::Value>>,
+) -> BedrockBlock {
+    let mut states = HashMap::new();
+
+    // Convert type: Java uses "top/bottom/double", Bedrock uses "top_slot_bit"
+    if let Some(props) = props {
+        if let Some(fastnbt::Value::String(slab_type)) = props.get("type") {
+            let top_slot = slab_type == "top";
+            states.insert(
+                "top_slot_bit".to_string(),
+                BedrockBlockStateValue::Bool(top_slot),
+            );
+            // Note: "double" slabs in Java become full blocks in Bedrock (different block ID)
+        }
+    }
+
+    // Default to bottom if not specified
+    if !states.contains_key("top_slot_bit") {
+        states.insert(
+            "top_slot_bit".to_string(),
+            BedrockBlockStateValue::Bool(false),
+        );
+    }
+
+    // Handle special slab name mappings (same as in to_bedrock_block)
+    let bedrock_name = match java_name {
+        "stone_slab" => "stone_block_slab",
+        "stone_brick_slab" => "stone_block_slab",
+        "oak_slab" => "wooden_slab",
+        "spruce_slab" => "wooden_slab",
+        "birch_slab" => "wooden_slab",
+        "jungle_slab" => "wooden_slab",
+        "acacia_slab" => "wooden_slab",
+        "dark_oak_slab" => "wooden_slab",
+        _ => java_name,
+    };
+
+    // Add wood_type for wooden slabs
+    if bedrock_name == "wooden_slab" {
+        let wood_type = java_name.trim_end_matches("_slab");
+        states.insert(
+            "wood_type".to_string(),
+            BedrockBlockStateValue::String(wood_type.to_string()),
+        );
+    }
+
+    // Add stone_slab_type for stone slabs
+    if bedrock_name == "stone_block_slab" {
+        let slab_type = if java_name == "stone_brick_slab" {
+            "stone_brick"
+        } else {
+            "stone"
+        };
+        states.insert(
+            "stone_slab_type".to_string(),
+            BedrockBlockStateValue::String(slab_type.to_string()),
+        );
+    }
+
+    BedrockBlock {
+        name: format!("minecraft:{bedrock_name}"),
+        states,
+    }
+}
+
+/// Convert Java log/wood block to Bedrock format with proper axis.
+fn convert_log(
+    java_name: &str,
+    props: Option<&std::collections::HashMap<String, fastnbt::Value>>,
+) -> BedrockBlock {
+    let bedrock_name = java_name;
+    let mut states = HashMap::new();
+
+    // Convert axis: Java uses "x/y/z", Bedrock uses "pillar_axis"
+    if let Some(props) = props {
+        if let Some(fastnbt::Value::String(axis)) = props.get("axis") {
+            states.insert(
+                "pillar_axis".to_string(),
+                BedrockBlockStateValue::String(axis.clone()),
+            );
+        }
+    }
+
+    // Default to y-axis if not specified
+    if states.is_empty() {
+        states.insert(
+            "pillar_axis".to_string(),
+            BedrockBlockStateValue::String("y".to_string()),
+        );
+    }
+
+    BedrockBlock {
+        name: format!("minecraft:{bedrock_name}"),
+        states,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::block_definitions::{AIR, GRASS_BLOCK, STONE};
+
+    #[test]
+    fn test_simple_blocks() {
+        let bedrock = to_bedrock_block(STONE);
+        assert_eq!(bedrock.name, "minecraft:stone");
+        assert!(bedrock.states.is_empty());
+
+        let bedrock = to_bedrock_block(AIR);
+        assert_eq!(bedrock.name, "minecraft:air");
+    }
+
+    #[test]
+    fn test_grass_block() {
+        let bedrock = to_bedrock_block(GRASS_BLOCK);
+        assert_eq!(bedrock.name, "minecraft:grass_block");
+    }
+
+    #[test]
+    fn test_colored_blocks() {
+        use crate::block_definitions::WHITE_CONCRETE;
+        let bedrock = to_bedrock_block(WHITE_CONCRETE);
+        assert_eq!(bedrock.name, "minecraft:concrete");
+        assert!(matches!(
+            bedrock.states.get("color"),
+            Some(BedrockBlockStateValue::String(s)) if s == "white"
+        ));
+    }
+
+    #[test]
+    fn test_stairs_with_properties() {
+        use crate::block_definitions::OAK_STAIRS;
+        use std::collections::HashMap as StdHashMap;
+
+        // Create Java properties for a south-facing stair
+        let mut props = StdHashMap::new();
+        props.insert(
+            "facing".to_string(),
+            fastnbt::Value::String("south".to_string()),
+        );
+        props.insert(
+            "half".to_string(),
+            fastnbt::Value::String("bottom".to_string()),
+        );
+        let java_props = fastnbt::Value::Compound(props);
+
+        let bedrock = to_bedrock_block_with_properties(OAK_STAIRS, Some(&java_props));
+        assert_eq!(bedrock.name, "minecraft:oak_stairs");
+
+        // Check weirdo_direction is set correctly (south = 2)
+        assert!(matches!(
+            bedrock.states.get("weirdo_direction"),
+            Some(BedrockBlockStateValue::Int(2))
+        ));
+
+        // Check upside_down_bit is false for bottom half
+        assert!(matches!(
+            bedrock.states.get("upside_down_bit"),
+            Some(BedrockBlockStateValue::Bool(false))
+        ));
+    }
+
+    #[test]
+    fn test_stairs_upside_down() {
+        use crate::block_definitions::STONE_BRICK_STAIRS;
+        use std::collections::HashMap as StdHashMap;
+
+        // Create Java properties for an upside-down north-facing stair
+        let mut props = StdHashMap::new();
+        props.insert(
+            "facing".to_string(),
+            fastnbt::Value::String("north".to_string()),
+        );
+        props.insert(
+            "half".to_string(),
+            fastnbt::Value::String("top".to_string()),
+        );
+        let java_props = fastnbt::Value::Compound(props);
+
+        let bedrock = to_bedrock_block_with_properties(STONE_BRICK_STAIRS, Some(&java_props));
+
+        // Check weirdo_direction is set correctly (north = 3)
+        assert!(matches!(
+            bedrock.states.get("weirdo_direction"),
+            Some(BedrockBlockStateValue::Int(3))
+        ));
+
+        // Check upside_down_bit is true for top half
+        assert!(matches!(
+            bedrock.states.get("upside_down_bit"),
+            Some(BedrockBlockStateValue::Bool(true))
+        ));
+    }
+}

src/block_definitions.rs

@@ -236,7 +236,7 @@ impl Block {
             155 => "chest",
             156 => "red_carpet",
             157 => "anvil",
-            158 => "jukebox",
+            158 => "note_block",
             159 => "oak_door",
             160 => "brewing_stand",
             161 => "red_bed", // North head
@@ -667,7 +667,7 @@ pub const OAK_STAIRS: Block = Block::new(144);
 pub const CHEST: Block = Block::new(155);
 pub const RED_CARPET: Block = Block::new(156);
 pub const ANVIL: Block = Block::new(157);
-pub const JUKEBOX: Block = Block::new(158);
+pub const NOTE_BLOCK: Block = Block::new(158);
 pub const OAK_DOOR: Block = Block::new(159);
 pub const BREWING_STAND: Block = Block::new(160);
 pub const RED_BED_NORTH_HEAD: Block = Block::new(161);

src/clipping.rs

@@ -0,0 +1,706 @@
+// Sutherland-Hodgman polygon clipping and related geometry utilities.
+//
+// Provides bbox clipping for polygons, polylines, and water rings with
+// proper corner insertion for closed shapes.
+
+use crate::coordinate_system::cartesian::{XZBBox, XZPoint};
+use crate::osm_parser::ProcessedNode;
+use std::collections::HashMap;
+
+/// Clips a way to the bounding box using Sutherland-Hodgman for polygons or
+/// simple line clipping for polylines. Preserves endpoint IDs for ring assembly.
+pub fn clip_way_to_bbox(nodes: &[ProcessedNode], xzbbox: &XZBBox) -> Vec<ProcessedNode> {
+    if nodes.is_empty() {
+        return Vec::new();
+    }
+
+    let is_closed = is_closed_polygon(nodes);
+
+    if !is_closed {
+        return clip_polyline_to_bbox(nodes, xzbbox);
+    }
+
+    // If all nodes are inside the bbox, return unchanged
+    let has_nodes_outside = nodes
+        .iter()
+        .any(|node| !xzbbox.contains(&XZPoint::new(node.x, node.z)));
+
+    if !has_nodes_outside {
+        return nodes.to_vec();
+    }
+
+    let min_x = xzbbox.min_x() as f64;
+    let min_z = xzbbox.min_z() as f64;
+    let max_x = xzbbox.max_x() as f64;
+    let max_z = xzbbox.max_z() as f64;
+
+    let mut polygon: Vec<(f64, f64)> = nodes.iter().map(|n| (n.x as f64, n.z as f64)).collect();
+
+    polygon = clip_polygon_sutherland_hodgman(polygon, min_x, min_z, max_x, max_z);
+
+    if polygon.len() < 3 {
+        return Vec::new();
+    }
+
+    // Final clamping for floating-point errors
+    for p in &mut polygon {
+        p.0 = p.0.clamp(min_x, max_x);
+        p.1 = p.1.clamp(min_z, max_z);
+    }
+
+    let polygon = remove_consecutive_duplicates(polygon);
+    if polygon.len() < 3 {
+        return Vec::new();
+    }
+
+    let polygon = insert_bbox_corners(polygon, min_x, min_z, max_x, max_z);
+    let polygon = remove_consecutive_duplicates(polygon);
+    if polygon.len() < 3 {
+        return Vec::new();
+    }
+
+    let way_id = nodes.first().map(|n| n.id).unwrap_or(0);
+    assign_node_ids_preserving_endpoints(nodes, polygon, way_id)
+}
+
+/// Clips a water polygon ring to bbox using Sutherland-Hodgman (post-ring-merge).
+pub fn clip_water_ring_to_bbox(
+    ring: &[ProcessedNode],
+    xzbbox: &XZBBox,
+) -> Option<Vec<ProcessedNode>> {
+    if ring.is_empty() {
+        return None;
+    }
+
+    let min_x = xzbbox.min_x() as f64;
+    let min_z = xzbbox.min_z() as f64;
+    let max_x = xzbbox.max_x() as f64;
+    let max_z = xzbbox.max_z() as f64;
+
+    // Check if entire ring is inside bbox
+    let all_inside = ring.iter().all(|n| {
+        n.x as f64 >= min_x && n.x as f64 <= max_x && n.z as f64 >= min_z && n.z as f64 <= max_z
+    });
+
+    if all_inside {
+        return Some(ring.to_vec());
+    }
+
+    // Check if entire ring is outside bbox
+    if is_ring_outside_bbox(ring, min_x, min_z, max_x, max_z) {
+        return None;
+    }
+
+    // Convert to f64 coordinates and ensure closed
+    let mut polygon: Vec<(f64, f64)> = ring.iter().map(|n| (n.x as f64, n.z as f64)).collect();
+    if !polygon.is_empty() && polygon.first() != polygon.last() {
+        polygon.push(polygon[0]);
+    }
+
+    // Clip with full-range clamping (water uses simpler approach)
+    polygon = clip_polygon_sutherland_hodgman_simple(polygon, min_x, min_z, max_x, max_z);
+
+    if polygon.len() < 3 {
+        return None;
+    }
+
+    // Verify all points are within bbox
+    let all_points_inside = polygon
+        .iter()
+        .all(|&(x, z)| x >= min_x && x <= max_x && z >= min_z && z <= max_z);
+
+    if !all_points_inside {
+        eprintln!("ERROR: clip_water_ring_to_bbox produced points outside bbox!");
+        return None;
+    }
+
+    let polygon = insert_bbox_corners(polygon, min_x, min_z, max_x, max_z);
+    if polygon.len() < 3 {
+        return None;
+    }
+
+    // Convert back to ProcessedNode with synthetic IDs
+    let mut result: Vec<ProcessedNode> = polygon
+        .iter()
+        .enumerate()
+        .map(|(i, &(x, z))| ProcessedNode {
+            id: 1_000_000_000 + i as u64,
+            tags: HashMap::new(),
+            x: x.clamp(min_x, max_x).round() as i32,
+            z: z.clamp(min_z, max_z).round() as i32,
+        })
+        .collect();
+
+    // Close the loop by matching first and last ID
+    if !result.is_empty() {
+        let first_id = result[0].id;
+        result.last_mut().unwrap().id = first_id;
+    }
+
+    Some(result)
+}
+
+// ============================================================================
+// Internal helpers
+// ============================================================================
+
+/// Checks if a way forms a closed polygon.
+fn is_closed_polygon(nodes: &[ProcessedNode]) -> bool {
+    if nodes.len() < 3 {
+        return false;
+    }
+    let first = nodes.first().unwrap();
+    let last = nodes.last().unwrap();
+    first.id == last.id || (first.x == last.x && first.z == last.z)
+}
+
+/// Checks if an entire ring is outside the bbox.
+fn is_ring_outside_bbox(
+    ring: &[ProcessedNode],
+    min_x: f64,
+    min_z: f64,
+    max_x: f64,
+    max_z: f64,
+) -> bool {
+    let all_left = ring.iter().all(|n| (n.x as f64) < min_x);
+    let all_right = ring.iter().all(|n| (n.x as f64) > max_x);
+    let all_top = ring.iter().all(|n| (n.z as f64) < min_z);
+    let all_bottom = ring.iter().all(|n| (n.z as f64) > max_z);
+    all_left || all_right || all_top || all_bottom
+}
+
+/// Clips a polyline (open path) to the bounding box.
+fn clip_polyline_to_bbox(nodes: &[ProcessedNode], xzbbox: &XZBBox) -> Vec<ProcessedNode> {
+    if nodes.is_empty() {
+        return Vec::new();
+    }
+
+    let min_x = xzbbox.min_x() as f64;
+    let min_z = xzbbox.min_z() as f64;
+    let max_x = xzbbox.max_x() as f64;
+    let max_z = xzbbox.max_z() as f64;
+
+    let mut result = Vec::new();
+
+    for i in 0..nodes.len() {
+        let current = &nodes[i];
+        let current_point = (current.x as f64, current.z as f64);
+        let current_inside = point_in_bbox(current_point, min_x, min_z, max_x, max_z);
+
+        if current_inside {
+            result.push(current.clone());
+        }
+
+        if i + 1 < nodes.len() {
+            let next = &nodes[i + 1];
+            let next_point = (next.x as f64, next.z as f64);
+            let next_inside = point_in_bbox(next_point, min_x, min_z, max_x, max_z);
+
+            if current_inside != next_inside {
+                // One endpoint inside, one outside, find single intersection
+                let intersections =
+                    find_bbox_intersections(current_point, next_point, min_x, min_z, max_x, max_z);
+
+                for intersection in intersections {
+                    let synthetic_id = nodes[0]
+                        .id
+                        .wrapping_mul(10000000)
+                        .wrapping_add(result.len() as u64);
+                    result.push(ProcessedNode {
+                        id: synthetic_id,
+                        x: intersection.0.round() as i32,
+                        z: intersection.1.round() as i32,
+                        tags: HashMap::new(),
+                    });
+                }
+            } else if !current_inside && !next_inside {
+                // Both endpoints outside, segment might still cross through bbox
+                let mut intersections =
+                    find_bbox_intersections(current_point, next_point, min_x, min_z, max_x, max_z);
+
+                if intersections.len() >= 2 {
+                    // Sort intersections by distance from current point
+                    intersections.sort_by(|a, b| {
+                        let dist_a =
+                            (a.0 - current_point.0).powi(2) + (a.1 - current_point.1).powi(2);
+                        let dist_b =
+                            (b.0 - current_point.0).powi(2) + (b.1 - current_point.1).powi(2);
+                        dist_a
+                            .partial_cmp(&dist_b)
+                            .unwrap_or(std::cmp::Ordering::Equal)
+                    });
+
+                    for intersection in intersections {
+                        let synthetic_id = nodes[0]
+                            .id
+                            .wrapping_mul(10000000)
+                            .wrapping_add(result.len() as u64);
+                        result.push(ProcessedNode {
+                            id: synthetic_id,
+                            x: intersection.0.round() as i32,
+                            z: intersection.1.round() as i32,
+                            tags: HashMap::new(),
+                        });
+                    }
+                }
+            }
+        }
+    }
+
+    // Preserve endpoint IDs where possible
+    if result.len() >= 2 {
+        let tolerance = 50.0;
+        if let Some(first_orig) = nodes.first() {
+            if matches_endpoint(
+                (result[0].x as f64, result[0].z as f64),
+                first_orig,
+                tolerance,
+            ) {
+                result[0].id = first_orig.id;
+            }
+        }
+        if let Some(last_orig) = nodes.last() {
+            let last_idx = result.len() - 1;
+            if matches_endpoint(
+                (result[last_idx].x as f64, result[last_idx].z as f64),
+                last_orig,
+                tolerance,
+            ) {
+                result[last_idx].id = last_orig.id;
+            }
+        }
+    }
+
+    result
+}
+
+/// Sutherland-Hodgman polygon clipping with edge-specific clamping.
+fn clip_polygon_sutherland_hodgman(
+    mut polygon: Vec<(f64, f64)>,
+    min_x: f64,
+    min_z: f64,
+    max_x: f64,
+    max_z: f64,
+) -> Vec<(f64, f64)> {
+    // Edges: bottom, right, top, left (counter-clockwise traversal)
+    let bbox_edges = [
+        (min_x, min_z, max_x, min_z, 0), // Bottom: clamp z
+        (max_x, min_z, max_x, max_z, 1), // Right: clamp x
+        (max_x, max_z, min_x, max_z, 2), // Top: clamp z
+        (min_x, max_z, min_x, min_z, 3), // Left: clamp x
+    ];
+
+    for (edge_x1, edge_z1, edge_x2, edge_z2, edge_idx) in bbox_edges {
+        if polygon.is_empty() {
+            break;
+        }
+
+        let mut clipped = Vec::new();
+        let is_closed = !polygon.is_empty() && polygon.first() == polygon.last();
+        let edge_count = if is_closed {
+            polygon.len().saturating_sub(1)
+        } else {
+            polygon.len()
+        };
+
+        for i in 0..edge_count {
+            let current = polygon[i];
+            let next = polygon.get(i + 1).copied().unwrap_or(polygon[0]);
+
+            let current_inside = point_inside_edge(current, edge_x1, edge_z1, edge_x2, edge_z2);
+            let next_inside = point_inside_edge(next, edge_x1, edge_z1, edge_x2, edge_z2);
+
+            if next_inside {
+                if !current_inside {
+                    if let Some(mut intersection) = line_edge_intersection(
+                        current.0, current.1, next.0, next.1, edge_x1, edge_z1, edge_x2, edge_z2,
+                    ) {
+                        // Clamp to current edge only
+                        match edge_idx {
+                            0 => intersection.1 = min_z,
+                            1 => intersection.0 = max_x,
+                            2 => intersection.1 = max_z,
+                            3 => intersection.0 = min_x,
+                            _ => {}
+                        }
+                        clipped.push(intersection);
+                    }
+                }
+                clipped.push(next);
+            } else if current_inside {
+                if let Some(mut intersection) = line_edge_intersection(
+                    current.0, current.1, next.0, next.1, edge_x1, edge_z1, edge_x2, edge_z2,
+                ) {
+                    match edge_idx {
+                        0 => intersection.1 = min_z,
+                        1 => intersection.0 = max_x,
+                        2 => intersection.1 = max_z,
+                        3 => intersection.0 = min_x,
+                        _ => {}
+                    }
+                    clipped.push(intersection);
+                }
+            }
+        }
+
+        polygon = clipped;
+    }
+
+    polygon
+}
+
+/// Sutherland-Hodgman with full bbox clamping (simpler, for water rings).
+fn clip_polygon_sutherland_hodgman_simple(
+    mut polygon: Vec<(f64, f64)>,
+    min_x: f64,
+    min_z: f64,
+    max_x: f64,
+    max_z: f64,
+) -> Vec<(f64, f64)> {
+    let bbox_edges = [
+        (min_x, min_z, max_x, min_z),
+        (max_x, min_z, max_x, max_z),
+        (max_x, max_z, min_x, max_z),
+        (min_x, max_z, min_x, min_z),
+    ];
+
+    for (edge_x1, edge_z1, edge_x2, edge_z2) in bbox_edges {
+        if polygon.is_empty() {
+            break;
+        }
+
+        let mut clipped = Vec::new();
+
+        for i in 0..(polygon.len().saturating_sub(1)) {
+            let current = polygon[i];
+            let next = polygon[i + 1];
+
+            let current_inside = point_inside_edge(current, edge_x1, edge_z1, edge_x2, edge_z2);
+            let next_inside = point_inside_edge(next, edge_x1, edge_z1, edge_x2, edge_z2);
+
+            if next_inside {
+                if !current_inside {
+                    if let Some(mut intersection) = line_edge_intersection(
+                        current.0, current.1, next.0, next.1, edge_x1, edge_z1, edge_x2, edge_z2,
+                    ) {
+                        intersection.0 = intersection.0.clamp(min_x, max_x);
+                        intersection.1 = intersection.1.clamp(min_z, max_z);
+                        clipped.push(intersection);
+                    }
+                }
+                clipped.push(next);
+            } else if current_inside {
+                if let Some(mut intersection) = line_edge_intersection(
+                    current.0, current.1, next.0, next.1, edge_x1, edge_z1, edge_x2, edge_z2,
+                ) {
+                    intersection.0 = intersection.0.clamp(min_x, max_x);
+                    intersection.1 = intersection.1.clamp(min_z, max_z);
+                    clipped.push(intersection);
+                }
+            }
+        }
+
+        polygon = clipped;
+    }
+
+    polygon
+}
+
+/// Checks if point is inside bbox.
+fn point_in_bbox(point: (f64, f64), min_x: f64, min_z: f64, max_x: f64, max_z: f64) -> bool {
+    point.0 >= min_x && point.0 <= max_x && point.1 >= min_z && point.1 <= max_z
+}
+
+/// Checks if point is on the "inside" side of an edge (cross product test).
+fn point_inside_edge(
+    point: (f64, f64),
+    edge_x1: f64,
+    edge_z1: f64,
+    edge_x2: f64,
+    edge_z2: f64,
+) -> bool {
+    let edge_dx = edge_x2 - edge_x1;
+    let edge_dz = edge_z2 - edge_z1;
+    let point_dx = point.0 - edge_x1;
+    let point_dz = point.1 - edge_z1;
+    (edge_dx * point_dz - edge_dz * point_dx) >= 0.0
+}
+
+/// Finds intersection between a line segment and an edge.
+#[allow(clippy::too_many_arguments)]
+fn line_edge_intersection(
+    line_x1: f64,
+    line_z1: f64,
+    line_x2: f64,
+    line_z2: f64,
+    edge_x1: f64,
+    edge_z1: f64,
+    edge_x2: f64,
+    edge_z2: f64,
+) -> Option<(f64, f64)> {
+    let line_dx = line_x2 - line_x1;
+    let line_dz = line_z2 - line_z1;
+    let edge_dx = edge_x2 - edge_x1;
+    let edge_dz = edge_z2 - edge_z1;
+
+    let denom = line_dx * edge_dz - line_dz * edge_dx;
+    if denom.abs() < 1e-10 {
+        return None;
+    }
+
+    let dx = edge_x1 - line_x1;
+    let dz = edge_z1 - line_z1;
+    let t = (dx * edge_dz - dz * edge_dx) / denom;
+
+    if (0.0..=1.0).contains(&t) {
+        Some((line_x1 + t * line_dx, line_z1 + t * line_dz))
+    } else {
+        None
+    }
+}
+
+/// Finds intersections between a line segment and bbox edges.
+fn find_bbox_intersections(
+    start: (f64, f64),
+    end: (f64, f64),
+    min_x: f64,
+    min_z: f64,
+    max_x: f64,
+    max_z: f64,
+) -> Vec<(f64, f64)> {
+    let mut intersections = Vec::new();
+
+    let bbox_edges = [
+        (min_x, min_z, max_x, min_z),
+        (max_x, min_z, max_x, max_z),
+        (max_x, max_z, min_x, max_z),
+        (min_x, max_z, min_x, min_z),
+    ];
+
+    for (edge_x1, edge_z1, edge_x2, edge_z2) in bbox_edges {
+        if let Some(intersection) = line_edge_intersection(
+            start.0, start.1, end.0, end.1, edge_x1, edge_z1, edge_x2, edge_z2,
+        ) {
+            let on_edge = point_in_bbox(intersection, min_x, min_z, max_x, max_z)
+                && ((intersection.0 == min_x || intersection.0 == max_x)
+                    || (intersection.1 == min_z || intersection.1 == max_z));
+
+            if on_edge {
+                intersections.push(intersection);
+            }
+        }
+    }
+
+    intersections
+}
+
+/// Returns which bbox edge a point lies on: 0=bottom, 1=right, 2=top, 3=left, -1=interior.
+fn get_bbox_edge(point: (f64, f64), min_x: f64, min_z: f64, max_x: f64, max_z: f64) -> i32 {
+    let eps = 0.5;
+
+    let on_left = (point.0 - min_x).abs() < eps;
+    let on_right = (point.0 - max_x).abs() < eps;
+    let on_bottom = (point.1 - min_z).abs() < eps;
+    let on_top = (point.1 - max_z).abs() < eps;
+
+    // Handle corners (assign to edge in counter-clockwise order)
+    if on_bottom && on_left {
+        return 3;
+    }
+    if on_bottom && on_right {
+        return 0;
+    }
+    if on_top && on_right {
+        return 1;
+    }
+    if on_top && on_left {
+        return 2;
+    }
+
+    if on_bottom {
+        return 0;
+    }
+    if on_right {
+        return 1;
+    }
+    if on_top {
+        return 2;
+    }
+    if on_left {
+        return 3;
+    }
+
+    -1
+}
+
+/// Returns corners to insert when traversing from edge1 to edge2 via shorter path.
+fn get_corners_between_edges(
+    edge1: i32,
+    edge2: i32,
+    min_x: f64,
+    min_z: f64,
+    max_x: f64,
+    max_z: f64,
+) -> Vec<(f64, f64)> {
+    if edge1 == edge2 || edge1 < 0 || edge2 < 0 {
+        return Vec::new();
+    }
+
+    let corners = [
+        (max_x, min_z), // 0: bottom-right
+        (max_x, max_z), // 1: top-right
+        (min_x, max_z), // 2: top-left
+        (min_x, min_z), // 3: bottom-left
+    ];
+
+    let ccw_dist = ((edge2 - edge1 + 4) % 4) as usize;
+    let cw_dist = ((edge1 - edge2 + 4) % 4) as usize;
+
+    // Opposite edges: don't insert corners
+    if ccw_dist == 2 && cw_dist == 2 {
+        return Vec::new();
+    }
+
+    let mut result = Vec::new();
+
+    if ccw_dist <= cw_dist {
+        let mut current = edge1;
+        for _ in 0..ccw_dist {
+            result.push(corners[current as usize]);
+            current = (current + 1) % 4;
+        }
+    } else {
+        let mut current = edge1;
+        for _ in 0..cw_dist {
+            current = (current + 4 - 1) % 4;
+            result.push(corners[current as usize]);
+        }
+    }
+
+    result
+}
+
+/// Inserts bbox corners where polygon transitions between different bbox edges.
+fn insert_bbox_corners(
+    polygon: Vec<(f64, f64)>,
+    min_x: f64,
+    min_z: f64,
+    max_x: f64,
+    max_z: f64,
+) -> Vec<(f64, f64)> {
+    if polygon.len() < 3 {
+        return polygon;
+    }
+
+    let mut result = Vec::with_capacity(polygon.len() + 4);
+
+    for i in 0..polygon.len() {
+        let current = polygon[i];
+        let next = polygon[(i + 1) % polygon.len()];
+
+        result.push(current);
+
+        let edge1 = get_bbox_edge(current, min_x, min_z, max_x, max_z);
+        let edge2 = get_bbox_edge(next, min_x, min_z, max_x, max_z);
+
+        if edge1 >= 0 && edge2 >= 0 && edge1 != edge2 {
+            for corner in get_corners_between_edges(edge1, edge2, min_x, min_z, max_x, max_z) {
+                result.push(corner);
+            }
+        }
+    }
+
+    result
+}
+
+/// Removes consecutive duplicate points (within epsilon tolerance).
+fn remove_consecutive_duplicates(polygon: Vec<(f64, f64)>) -> Vec<(f64, f64)> {
+    if polygon.is_empty() {
+        return polygon;
+    }
+
+    let eps = 0.1;
+    let mut result: Vec<(f64, f64)> = Vec::with_capacity(polygon.len());
+
+    for p in &polygon {
+        if let Some(last) = result.last() {
+            if (p.0 - last.0).abs() < eps && (p.1 - last.1).abs() < eps {
+                continue;
+            }
+        }
+        result.push(*p);
+    }
+
+    // Check first/last duplicates for closed polygons
+    if result.len() > 1 {
+        let first = result.first().unwrap();
+        let last = result.last().unwrap();
+        if (first.0 - last.0).abs() < eps && (first.1 - last.1).abs() < eps {
+            result.pop();
+        }
+    }
+
+    result
+}
+
+/// Checks if a clipped coordinate matches an original endpoint.
+fn matches_endpoint(coord: (f64, f64), endpoint: &ProcessedNode, tolerance: f64) -> bool {
+    let dx = (coord.0 - endpoint.x as f64).abs();
+    let dz = (coord.1 - endpoint.z as f64).abs();
+    dx * dx + dz * dz < tolerance * tolerance
+}
+
+/// Assigns node IDs to clipped coordinates, preserving original endpoint IDs.
+fn assign_node_ids_preserving_endpoints(
+    original_nodes: &[ProcessedNode],
+    clipped_coords: Vec<(f64, f64)>,
+    way_id: u64,
+) -> Vec<ProcessedNode> {
+    if clipped_coords.is_empty() {
+        return Vec::new();
+    }
+
+    let original_first = original_nodes.first();
+    let original_last = original_nodes.last();
+    let tolerance = 50.0;
+    let last_index = clipped_coords.len() - 1;
+
+    clipped_coords
+        .into_iter()
+        .enumerate()
+        .map(|(i, coord)| {
+            let is_first = i == 0;
+            let is_last = i == last_index;
+
+            if is_first || is_last {
+                if let Some(first) = original_first {
+                    if matches_endpoint(coord, first, tolerance) {
+                        return ProcessedNode {
+                            id: first.id,
+                            x: coord.0.round() as i32,
+                            z: coord.1.round() as i32,
+                            tags: HashMap::new(),
+                        };
+                    }
+                }
+                if let Some(last) = original_last {
+                    if matches_endpoint(coord, last, tolerance) {
+                        return ProcessedNode {
+                            id: last.id,
+                            x: coord.0.round() as i32,
+                            z: coord.1.round() as i32,
+                            tags: HashMap::new(),
+                        };
+                    }
+                }
+            }
+
+            ProcessedNode {
+                id: way_id.wrapping_mul(10000000).wrapping_add(i as u64),
+                x: coord.0.round() as i32,
+                z: coord.1.round() as i32,
+                tags: HashMap::new(),
+            }
+        })
+        .collect()
+}

src/data_processing.rs

@@ -1,35 +1,92 @@
 use crate::args::Args;
 use crate::block_definitions::{BEDROCK, DIRT, GRASS_BLOCK, STONE};
 use crate::coordinate_system::cartesian::XZBBox;
+use crate::coordinate_system::geographic::LLBBox;
 use crate::element_processing::*;
+use crate::floodfill_cache::FloodFillCache;
 use crate::ground::Ground;
+use crate::map_renderer;
 use crate::osm_parser::ProcessedElement;
-use crate::progress::emit_gui_progress_update;
-use crate::world_editor::WorldEditor;
+use crate::progress::{emit_gui_progress_update, emit_map_preview_ready, emit_open_mcworld_file};
+#[cfg(feature = "gui")]
+use crate::telemetry::{send_log, LogLevel};
+use crate::world_editor::{WorldEditor, WorldFormat};
 use colored::Colorize;
 use indicatif::{ProgressBar, ProgressStyle};
+use std::path::PathBuf;
+use std::sync::Arc;
 
 pub const MIN_Y: i32 = -64;
 
+/// Generation options that can be passed separately from CLI Args
+#[derive(Clone)]
+pub struct GenerationOptions {
+    pub path: PathBuf,
+    pub format: WorldFormat,
+    pub level_name: Option<String>,
+    pub spawn_point: Option<(i32, i32)>,
+}
+
 pub fn generate_world(
     elements: Vec<ProcessedElement>,
     xzbbox: XZBBox,
+    llbbox: LLBBox,
     ground: Ground,
     args: &Args,
 ) -> Result<(), String> {
-    let region_dir: String = format!("{}/region", args.path);
-    let mut editor: WorldEditor = WorldEditor::new(&region_dir, &xzbbox);
+    // Default to Java format when called from CLI
+    let options = GenerationOptions {
+        path: args.path.clone(),
+        format: WorldFormat::JavaAnvil,
+        level_name: None,
+        spawn_point: None,
+    };
+    generate_world_with_options(elements, xzbbox, llbbox, ground, args, options).map(|_| ())
+}
+
+/// Generate world with explicit format options (used by GUI for Bedrock support)
+pub fn generate_world_with_options(
+    elements: Vec<ProcessedElement>,
+    xzbbox: XZBBox,
+    llbbox: LLBBox,
+    ground: Ground,
+    args: &Args,
+    options: GenerationOptions,
+) -> Result<PathBuf, String> {
+    let output_path = options.path.clone();
+    let world_format = options.format;
+
+    // Create editor with appropriate format
+    let mut editor: WorldEditor = WorldEditor::new_with_format_and_name(
+        options.path,
+        &xzbbox,
+        llbbox,
+        options.format,
+        options.level_name.clone(),
+        options.spawn_point,
+    );
+    let ground = Arc::new(ground);
 
     println!("{} Processing data...", "[4/7]".bold());
 
     // Set ground reference in the editor to enable elevation-aware block placement
-    editor.set_ground(&ground);
+    editor.set_ground(Arc::clone(&ground));
 
     println!("{} Processing terrain...", "[5/7]".bold());
     emit_gui_progress_update(25.0, "Processing terrain...");
 
+    // Run both precomputations concurrently using rayon::join
+    // This overlaps highway connectivity map building with flood fill computation
+    let timeout_ref = args.timeout.as_ref();
+    let (highway_connectivity, mut flood_fill_cache) = rayon::join(
+        || highways::build_highway_connectivity_map(&elements),
+        || FloodFillCache::precompute(&elements, timeout_ref),
+    );
+    println!("Pre-computed {} flood fills", flood_fill_cache.way_count());
+
     // Process data
     let elements_count: usize = elements.len();
+    let mut elements = elements; // Take ownership for consuming
     let process_pb: ProgressBar = ProgressBar::new(elements_count as u64);
     process_pb.set_style(ProgressStyle::default_bar()
         .template("{spinner:.green} [{elapsed_precise}] [{bar:45.white/black}] {pos}/{len} elements ({eta}) {msg}")
@@ -40,7 +97,8 @@ pub fn generate_world(
     let mut current_progress_prcs: f64 = 25.0;
     let mut last_emitted_progress: f64 = current_progress_prcs;
 
-    for element in &elements {
+    // Process elements by draining in insertion order
+    for element in elements.drain(..) {
         process_pb.inc(1);
         current_progress_prcs += progress_increment_prcs;
         if (current_progress_prcs - last_emitted_progress).abs() > 0.25 {
@@ -58,36 +116,51 @@ pub fn generate_world(
             process_pb.set_message("");
         }
 
-        match element {
+        match &element {
             ProcessedElement::Way(way) => {
                 if way.tags.contains_key("building") || way.tags.contains_key("building:part") {
-                    buildings::generate_buildings(&mut editor, way, args, None);
+                    buildings::generate_buildings(&mut editor, way, args, None, &flood_fill_cache);
                 } else if way.tags.contains_key("highway") {
-                    highways::generate_highways(&mut editor, element, args);
+                    highways::generate_highways(
+                        &mut editor,
+                        &element,
+                        args,
+                        &highway_connectivity,
+                        &flood_fill_cache,
+                    );
                 } else if way.tags.contains_key("landuse") {
-                    landuse::generate_landuse(&mut editor, way, args);
+                    landuse::generate_landuse(&mut editor, way, args, &flood_fill_cache);
                 } else if way.tags.contains_key("natural") {
-                    natural::generate_natural(&mut editor, element, args);
+                    natural::generate_natural(&mut editor, &element, args, &flood_fill_cache);
                 } else if way.tags.contains_key("amenity") {
-                    amenities::generate_amenities(&mut editor, element, args);
+                    amenities::generate_amenities(&mut editor, &element, args, &flood_fill_cache);
                 } else if way.tags.contains_key("leisure") {
-                    leisure::generate_leisure(&mut editor, way, args);
+                    leisure::generate_leisure(&mut editor, way, args, &flood_fill_cache);
                 } else if way.tags.contains_key("barrier") {
-                    barriers::generate_barriers(&mut editor, element);
-                } else if way.tags.contains_key("waterway") {
-                    waterways::generate_waterways(&mut editor, way);
+                    barriers::generate_barriers(&mut editor, &element);
+                } else if let Some(val) = way.tags.get("waterway") {
+                    if val == "dock" {
+                        // docks count as water areas
+                        water_areas::generate_water_area_from_way(&mut editor, way, &xzbbox);
+                    } else {
+                        waterways::generate_waterways(&mut editor, way);
+                    }
                 } else if way.tags.contains_key("bridge") {
                     //bridges::generate_bridges(&mut editor, way, ground_level); // TODO FIX
                 } else if way.tags.contains_key("railway") {
                     railways::generate_railways(&mut editor, way);
+                } else if way.tags.contains_key("roller_coaster") {
+                    railways::generate_roller_coaster(&mut editor, way);
                 } else if way.tags.contains_key("aeroway") || way.tags.contains_key("area:aeroway")
                 {
                     highways::generate_aeroway(&mut editor, way, args);
                 } else if way.tags.get("service") == Some(&"siding".to_string()) {
                     highways::generate_siding(&mut editor, way);
                 } else if way.tags.contains_key("man_made") {
-                    man_made::generate_man_made(&mut editor, element, args);
+                    man_made::generate_man_made(&mut editor, &element, args);
                 }
+                // Release flood fill cache entry for this way
+                flood_fill_cache.remove_way(way.id);
             }
             ProcessedElement::Node(node) => {
                 if node.tags.contains_key("door") || node.tags.contains_key("entrance") {
@@ -95,13 +168,19 @@ pub fn generate_world(
                 } else if node.tags.contains_key("natural")
                     && node.tags.get("natural") == Some(&"tree".to_string())
                 {
-                    natural::generate_natural(&mut editor, element, args);
+                    natural::generate_natural(&mut editor, &element, args, &flood_fill_cache);
                 } else if node.tags.contains_key("amenity") {
-                    amenities::generate_amenities(&mut editor, element, args);
+                    amenities::generate_amenities(&mut editor, &element, args, &flood_fill_cache);
                 } else if node.tags.contains_key("barrier") {
                     barriers::generate_barrier_nodes(&mut editor, node);
                 } else if node.tags.contains_key("highway") {
-                    highways::generate_highways(&mut editor, element, args);
+                    highways::generate_highways(
+                        &mut editor,
+                        &element,
+                        args,
+                        &highway_connectivity,
+                        &flood_fill_cache,
+                    );
                 } else if node.tags.contains_key("tourism") {
                     tourisms::generate_tourisms(&mut editor, node);
                 } else if node.tags.contains_key("man_made") {
@@ -110,30 +189,58 @@ pub fn generate_world(
             }
             ProcessedElement::Relation(rel) => {
                 if rel.tags.contains_key("building") || rel.tags.contains_key("building:part") {
-                    buildings::generate_building_from_relation(&mut editor, rel, args);
-                } else if rel.tags.contains_key("water")
-                    || rel.tags.get("natural") == Some(&"water".to_string())
-                {
-                    water_areas::generate_water_areas(&mut editor, rel);
-                } else if rel.tags.contains_key("natural") {
-                    natural::generate_natural_from_relation(&mut editor, rel, args);
-                } else if rel.tags.contains_key("landuse") {
-                    landuse::generate_landuse_from_relation(&mut editor, rel, args);
-                } else if rel.tags.get("leisure") == Some(&"park".to_string()) {
-                    leisure::generate_leisure_from_relation(&mut editor, rel, args);
-                } else if rel.tags.contains_key("man_made") {
-                    man_made::generate_man_made(
+                    buildings::generate_building_from_relation(
                         &mut editor,
-                        &ProcessedElement::Relation(rel.clone()),
+                        rel,
                         args,
+                        &flood_fill_cache,
                     );
+                } else if rel.tags.contains_key("water")
+                    || rel
+                        .tags
+                        .get("natural")
+                        .map(|val| val == "water" || val == "bay")
+                        .unwrap_or(false)
+                {
+                    water_areas::generate_water_areas_from_relation(&mut editor, rel, &xzbbox);
+                } else if rel.tags.contains_key("natural") {
+                    natural::generate_natural_from_relation(
+                        &mut editor,
+                        rel,
+                        args,
+                        &flood_fill_cache,
+                    );
+                } else if rel.tags.contains_key("landuse") {
+                    landuse::generate_landuse_from_relation(
+                        &mut editor,
+                        rel,
+                        args,
+                        &flood_fill_cache,
+                    );
+                } else if rel.tags.get("leisure") == Some(&"park".to_string()) {
+                    leisure::generate_leisure_from_relation(
+                        &mut editor,
+                        rel,
+                        args,
+                        &flood_fill_cache,
+                    );
+                } else if rel.tags.contains_key("man_made") {
+                    man_made::generate_man_made(&mut editor, &element, args);
                 }
+                // Release flood fill cache entries for all ways in this relation
+                let way_ids: Vec<u64> = rel.members.iter().map(|m| m.way.id).collect();
+                flood_fill_cache.remove_relation_ways(&way_ids);
             }
         }
+        // Element is dropped here, freeing its memory immediately
     }
 
     process_pb.finish();
 
+    // Drop remaining caches
+    drop(highway_connectivity);
+    drop(flood_fill_cache);
+
     // Generate ground layer
     let total_blocks: u64 = xzbbox.bounding_rect().total_blocks();
     let desired_updates: u64 = 1500;
@@ -159,42 +266,61 @@ pub fn generate_world(
 
     let groundlayer_block = GRASS_BLOCK;
 
-    for x in xzbbox.min_x()..=xzbbox.max_x() {
-        for z in xzbbox.min_z()..=xzbbox.max_z() {
-            // Add default dirt and grass layer if there isn't a stone layer already
-            if !editor.check_for_block(x, 0, z, Some(&[STONE])) {
-                editor.set_block(groundlayer_block, x, 0, z, None, None);
-                editor.set_block(DIRT, x, -1, z, None, None);
-                editor.set_block(DIRT, x, -2, z, None, None);
-            }
+    // Process ground generation chunk-by-chunk for better cache locality.
+    // This keeps the same region/chunk HashMap entries hot in CPU cache,
+    // rather than jumping between regions on every Z iteration.
+    let min_chunk_x = xzbbox.min_x() >> 4;
+    let max_chunk_x = xzbbox.max_x() >> 4;
+    let min_chunk_z = xzbbox.min_z() >> 4;
+    let max_chunk_z = xzbbox.max_z() >> 4;
 
-            // Fill underground with stone
-            if args.fillground {
-                // Fill from bedrock+1 to 3 blocks below ground with stone
-                editor.fill_blocks_absolute(
-                    STONE,
-                    x,
-                    MIN_Y + 1,
-                    z,
-                    x,
-                    editor.get_absolute_y(x, -3, z),
-                    z,
-                    None,
-                    None,
-                );
-            }
-            // Generate a bedrock level at MIN_Y
-            editor.set_block_absolute(BEDROCK, x, MIN_Y, z, None, Some(&[BEDROCK]));
+    for chunk_x in min_chunk_x..=max_chunk_x {
+        for chunk_z in min_chunk_z..=max_chunk_z {
+            // Calculate the block range for this chunk, clamped to bbox
+            let chunk_min_x = (chunk_x << 4).max(xzbbox.min_x());
+            let chunk_max_x = ((chunk_x << 4) + 15).min(xzbbox.max_x());
+            let chunk_min_z = (chunk_z << 4).max(xzbbox.min_z());
+            let chunk_max_z = ((chunk_z << 4) + 15).min(xzbbox.max_z());
 
-            block_counter += 1;
-            if block_counter % batch_size == 0 {
-                ground_pb.inc(batch_size);
-            }
+            for x in chunk_min_x..=chunk_max_x {
+                for z in chunk_min_z..=chunk_max_z {
+                    // Add default dirt and grass layer if there isn't a stone layer already
+                    if !editor.check_for_block(x, 0, z, Some(&[STONE])) {
+                        editor.set_block(groundlayer_block, x, 0, z, None, None);
+                        editor.set_block(DIRT, x, -1, z, None, None);
+                        editor.set_block(DIRT, x, -2, z, None, None);
+                    }
 
-            gui_progress_grnd += progress_increment_grnd;
-            if (gui_progress_grnd - last_emitted_progress).abs() > 0.25 {
-                emit_gui_progress_update(gui_progress_grnd, "");
-                last_emitted_progress = gui_progress_grnd;
+                    // Fill underground with stone
+                    if args.fillground {
+                        // Fill from bedrock+1 to 3 blocks below ground with stone
+                        editor.fill_blocks_absolute(
+                            STONE,
+                            x,
+                            MIN_Y + 1,
+                            z,
+                            x,
+                            editor.get_absolute_y(x, -3, z),
+                            z,
+                            None,
+                            None,
+                        );
+                    }
+                    // Generate a bedrock level at MIN_Y
+                    editor.set_block_absolute(BEDROCK, x, MIN_Y, z, None, Some(&[BEDROCK]));
+
+                    block_counter += 1;
+                    #[allow(clippy::manual_is_multiple_of)]
+                    if block_counter % batch_size == 0 {
+                        ground_pb.inc(batch_size);
+                    }
+
+                    gui_progress_grnd += progress_increment_grnd;
+                    if (gui_progress_grnd - last_emitted_progress).abs() > 0.25 {
+                        emit_gui_progress_update(gui_progress_grnd, "");
+                        last_emitted_progress = gui_progress_grnd;
+                    }
+                }
             }
         }
     }
@@ -217,30 +343,109 @@ pub fn generate_world(
     // Save world
     editor.save();
 
+    emit_gui_progress_update(99.0, "Finalizing world...");
+
     // Update player spawn Y coordinate based on terrain height after generation
     #[cfg(feature = "gui")]
-    if let Some(spawn_coords) = &args.spawn_point {
-        use crate::gui::update_player_spawn_y_after_generation;
-        let bbox_string = format!(
-            "{},{},{},{}",
-            args.bbox.min().lng(),
-            args.bbox.min().lat(),
-            args.bbox.max().lng(),
-            args.bbox.max().lat()
-        );
+    if world_format == WorldFormat::JavaAnvil {
+        if let Some(spawn_coords) = &args.spawn_point {
+            use crate::gui::update_player_spawn_y_after_generation;
+            let bbox_string = format!(
+                "{},{},{},{}",
+                args.bbox.min().lng(),
+                args.bbox.min().lat(),
+                args.bbox.max().lng(),
+                args.bbox.max().lat()
+            );
 
-        if let Err(e) = update_player_spawn_y_after_generation(
-            &args.path,
-            Some(*spawn_coords),
-            bbox_string,
-            args.scale,
-            &ground,
-        ) {
-            eprintln!("Warning: Failed to update spawn point Y coordinate: {e}");
+            if let Err(e) = update_player_spawn_y_after_generation(
+                &args.path,
+                Some(*spawn_coords),
+                bbox_string,
+                args.scale,
+                ground.as_ref(),
+            ) {
+                let warning_msg = format!("Failed to update spawn point Y coordinate: {}", e);
+                eprintln!("Warning: {}", warning_msg);
+                #[cfg(feature = "gui")]
+                send_log(LogLevel::Warning, &warning_msg);
+            }
         }
     }
 
-    emit_gui_progress_update(100.0, "Done! World generation completed.");
-    println!("{}", "Done! World generation completed.".green().bold());
-    Ok(())
+    // For Bedrock format, emit event to open the mcworld file
+    if world_format == WorldFormat::BedrockMcWorld {
+        if let Some(path_str) = output_path.to_str() {
+            emit_open_mcworld_file(path_str);
+        }
+    }
+
+    Ok(output_path)
+}
+
+/// Information needed to generate a map preview after world generation is complete
+#[derive(Clone)]
+pub struct MapPreviewInfo {
+    pub world_path: PathBuf,
+    pub min_x: i32,
+    pub max_x: i32,
+    pub min_z: i32,
+    pub max_z: i32,
+    pub world_area: i64,
+}
+
+impl MapPreviewInfo {
+    /// Create MapPreviewInfo from world bounds
+    pub fn new(world_path: PathBuf, xzbbox: &XZBBox) -> Self {
+        let world_width = (xzbbox.max_x() - xzbbox.min_x()) as i64;
+        let world_height = (xzbbox.max_z() - xzbbox.min_z()) as i64;
+        Self {
+            world_path,
+            min_x: xzbbox.min_x(),
+            max_x: xzbbox.max_x(),
+            min_z: xzbbox.min_z(),
+            max_z: xzbbox.max_z(),
+            world_area: world_width * world_height,
+        }
+    }
+}
+
+/// Maximum area for which map preview generation is allowed (to avoid memory issues)
+pub const MAX_MAP_PREVIEW_AREA: i64 = 6400 * 6900;
+
+/// Start map preview generation in a background thread.
+/// This should be called AFTER the world generation is complete, the session lock is released,
+/// and the GUI has been notified of 100% completion.
+///
+/// For Java worlds only, and only if the world area is within limits.
+pub fn start_map_preview_generation(info: MapPreviewInfo) {
+    if info.world_area > MAX_MAP_PREVIEW_AREA {
+        return;
+    }
+
+    std::thread::spawn(move || {
+        // Use catch_unwind to prevent any panic from affecting the application
+        let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+            map_renderer::render_world_map(
+                &info.world_path,
+                info.min_x,
+                info.max_x,
+                info.min_z,
+                info.max_z,
+            )
+        }));
+
+        match result {
+            Ok(Ok(_path)) => {
+                // Notify the GUI that the map preview is ready
+                emit_map_preview_ready();
+            }
+            Ok(Err(e)) => {
+                eprintln!("Warning: Failed to generate map preview: {}", e);
+            }
+            Err(_) => {
+                eprintln!("Warning: Map preview generation panicked unexpectedly");
+            }
+        }
+    });
 }

src/deterministic_rng.rs

@@ -0,0 +1,127 @@
+//! Deterministic random number generation for consistent element processing.
+//!
+//! This module provides seeded RNG that ensures the same element always produces
+//! the same random values, regardless of processing order. This is essential for
+//! region-by-region streaming where the same element may be processed multiple times
+//! (once for each region it touches).
+//!
+//! # Example
+//! ```ignore
+//! let mut rng = element_rng(element_id);
+//! let color = rng.gen_bool(0.5); // Always same result for same element_id
+//! ```
+
+use rand::SeedableRng;
+use rand_chacha::ChaCha8Rng;
+
+/// Creates a deterministic RNG seeded from an element ID.
+///
+/// The same element ID will always produce the same sequence of random values,
+/// ensuring consistent results when an element is processed multiple times
+/// (e.g., once per region it touches during streaming).
+///
+/// # Arguments
+/// * `element_id` - The unique OSM element ID (way ID, node ID, or relation ID)
+///
+/// # Returns
+/// A seeded ChaCha8Rng that will produce deterministic random values
+#[inline]
+pub fn element_rng(element_id: u64) -> ChaCha8Rng {
+    ChaCha8Rng::seed_from_u64(element_id)
+}
+
+/// Creates a deterministic RNG seeded from an element ID with an additional salt.
+///
+/// Use this when you need multiple independent random sequences for the same element.
+/// For example, one sequence for wall colors and another for roof style.
+///
+/// # Arguments
+/// * `element_id` - The unique OSM element ID
+/// * `salt` - Additional value to create a different sequence (e.g., use different
+///   salt values for different purposes within the same element)
+#[inline]
+#[allow(dead_code)]
+pub fn element_rng_salted(element_id: u64, salt: u64) -> ChaCha8Rng {
+    // Combine element_id and salt using XOR and bit rotation to avoid collisions
+    let combined = element_id ^ salt.rotate_left(32);
+    ChaCha8Rng::seed_from_u64(combined)
+}
+
+/// Creates a deterministic RNG seeded from coordinates.
+///
+/// Use this for per-block randomness that needs to be consistent regardless
+/// of processing order (e.g., random flower placement within a natural area).
+///
+/// # Arguments
+/// * `x` - X coordinate
+/// * `z` - Z coordinate
+/// * `element_id` - The element ID for additional uniqueness
+#[inline]
+pub fn coord_rng(x: i32, z: i32, element_id: u64) -> ChaCha8Rng {
+    // Combine coordinates and element_id into a seed.
+    // Cast through u32 to handle negative coordinates consistently.
+    let coord_part = ((x as u32 as i64) << 32) | (z as u32 as i64);
+    let seed = (coord_part as u64) ^ element_id;
+    ChaCha8Rng::seed_from_u64(seed)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use rand::Rng;
+
+    #[test]
+    fn test_element_rng_deterministic() {
+        let mut rng1 = element_rng(12345);
+        let mut rng2 = element_rng(12345);
+
+        // Same seed should produce same sequence
+        for _ in 0..100 {
+            assert_eq!(rng1.gen::<u64>(), rng2.gen::<u64>());
+        }
+    }
+
+    #[test]
+    fn test_different_elements_different_values() {
+        let mut rng1 = element_rng(12345);
+        let mut rng2 = element_rng(12346);
+
+        // Different seeds should (almost certainly) produce different values
+        let v1: u64 = rng1.gen();
+        let v2: u64 = rng2.gen();
+        assert_ne!(v1, v2);
+    }
+
+    #[test]
+    fn test_salted_rng_different_from_base() {
+        let mut rng1 = element_rng(12345);
+        let mut rng2 = element_rng_salted(12345, 1);
+
+        let v1: u64 = rng1.gen();
+        let v2: u64 = rng2.gen();
+        assert_ne!(v1, v2);
+    }
+
+    #[test]
+    fn test_coord_rng_deterministic() {
+        let mut rng1 = coord_rng(100, 200, 12345);
+        let mut rng2 = coord_rng(100, 200, 12345);
+
+        assert_eq!(rng1.gen::<u64>(), rng2.gen::<u64>());
+    }
+
+    #[test]
+    fn test_coord_rng_negative_coordinates() {
+        // Negative coordinates are common in Minecraft worlds
+        let mut rng1 = coord_rng(-100, -200, 12345);
+        let mut rng2 = coord_rng(-100, -200, 12345);
+
+        assert_eq!(rng1.gen::<u64>(), rng2.gen::<u64>());
+
+        // Ensure different negative coords produce different seeds
+        let mut rng3 = coord_rng(-100, -200, 12345);
+        let mut rng4 = coord_rng(-101, -200, 12345);
+
+        assert_ne!(rng3.gen::<u64>(), rng4.gen::<u64>());
+    }
+}

src/element_processing/amenities.rs

@@ -2,11 +2,19 @@ use crate::args::Args;
 use crate::block_definitions::*;
 use crate::bresenham::bresenham_line;
 use crate::coordinate_system::cartesian::XZPoint;
-use crate::floodfill::flood_fill_area;
+use crate::deterministic_rng::element_rng;
+use crate::floodfill::flood_fill_area; // Needed for inline amenity flood fills
+use crate::floodfill_cache::FloodFillCache;
 use crate::osm_parser::ProcessedElement;
 use crate::world_editor::WorldEditor;
+use rand::Rng;
 
-pub fn generate_amenities(editor: &mut WorldEditor, element: &ProcessedElement, args: &Args) {
+pub fn generate_amenities(
+    editor: &mut WorldEditor,
+    element: &ProcessedElement,
+    args: &Args,
+    flood_fill_cache: &FloodFillCache,
+) {
     // Skip if 'layer' or 'level' is negative in the tags
     if let Some(layer) = element.tags().get("layer") {
         if layer.parse::<i32>().unwrap_or(0) < 0 {
@@ -42,18 +50,14 @@ pub fn generate_amenities(editor: &mut WorldEditor, element: &ProcessedElement,
                 let ground_block: Block = OAK_PLANKS;
                 let roof_block: Block = STONE_BLOCK_SLAB;
 
-                let polygon_coords: Vec<(i32, i32)> = element
-                    .nodes()
-                    .map(|n: &crate::osm_parser::ProcessedNode| (n.x, n.z))
-                    .collect();
+                // Use pre-computed flood fill from cache
+                let floor_area: Vec<(i32, i32)> =
+                    flood_fill_cache.get_or_compute_element(element, args.timeout.as_ref());
 
-                if polygon_coords.is_empty() {
+                if floor_area.is_empty() {
                     return;
                 }
 
-                let floor_area: Vec<(i32, i32)> =
-                    flood_fill_area(&polygon_coords, args.timeout.as_ref());
-
                 // Fill the floor area
                 for (x, z) in floor_area.iter() {
                     editor.set_block(ground_block, *x, 0, *z, None, None);
@@ -80,8 +84,10 @@ pub fn generate_amenities(editor: &mut WorldEditor, element: &ProcessedElement,
             "bench" => {
                 // Place a bench
                 if let Some(pt) = first_node {
-                    // 50% chance to 90 degrees rotate the bench using if
-                    if rand::random::<bool>() {
+                    // Use deterministic RNG for consistent bench orientation across region boundaries
+                    let mut rng = element_rng(element.id());
+                    // 50% chance to 90 degrees rotate the bench
+                    if rng.gen_bool(0.5) {
                         editor.set_block(SMOOTH_STONE, pt.x, 1, pt.z, None, None);
                         editor.set_block(OAK_LOG, pt.x + 1, 1, pt.z, None, None);
                         editor.set_block(OAK_LOG, pt.x - 1, 1, pt.z, None, None);
@@ -92,22 +98,12 @@ pub fn generate_amenities(editor: &mut WorldEditor, element: &ProcessedElement,
                     }
                 }
             }
-            "vending" => {
-                // Place vending machine blocks
-                if let Some(pt) = first_node {
-                    editor.set_block(IRON_BLOCK, pt.x, 1, pt.z, None, None);
-                    editor.set_block(IRON_BLOCK, pt.x, 2, pt.z, None, None);
-                }
-            }
             "shelter" => {
                 let roof_block: Block = STONE_BRICK_SLAB;
 
-                let polygon_coords: Vec<(i32, i32)> = element
-                    .nodes()
-                    .map(|n: &crate::osm_parser::ProcessedNode| (n.x, n.z))
-                    .collect();
+                // Use pre-computed flood fill from cache
                 let roof_area: Vec<(i32, i32)> =
-                    flood_fill_area(&polygon_coords, args.timeout.as_ref());
+                    flood_fill_cache.get_or_compute_element(element, args.timeout.as_ref());
 
                 // Place fences and roof slabs at each corner node directly
                 for node in element.nodes() {

src/element_processing/buildings.rs

@@ -3,8 +3,9 @@ use crate::block_definitions::*;
 use crate::bresenham::bresenham_line;
 use crate::colors::color_text_to_rgb_tuple;
 use crate::coordinate_system::cartesian::XZPoint;
+use crate::deterministic_rng::element_rng;
 use crate::element_processing::subprocessor::buildings_interior::generate_building_interior;
-use crate::floodfill::flood_fill_area;
+use crate::floodfill_cache::FloodFillCache;
 use crate::osm_parser::{ProcessedMemberRole, ProcessedRelation, ProcessedWay};
 use crate::world_editor::WorldEditor;
 use rand::Rng;
@@ -28,6 +29,7 @@ pub fn generate_buildings(
     element: &ProcessedWay,
     args: &Args,
     relation_levels: Option<i32>,
+    flood_fill_cache: &FloodFillCache,
 ) {
     // Get min_level first so we can use it both for start_level and building height calculations
     let min_level = if let Some(min_level_str) = element.tags.get("building:min_level") {
@@ -43,10 +45,9 @@ pub fn generate_buildings(
     let scale_factor = args.scale;
     let min_level_offset = multiply_scale(min_level * 4, scale_factor);
 
-    // Cache floodfill result: compute once and reuse throughout
-    let polygon_coords: Vec<(i32, i32)> = element.nodes.iter().map(|n| (n.x, n.z)).collect();
+    // Use pre-computed flood fill from cache
     let cached_floor_area: Vec<(i32, i32)> =
-        flood_fill_area(&polygon_coords, args.timeout.as_ref());
+        flood_fill_cache.get_or_compute(element, args.timeout.as_ref());
     let cached_footprint_size = cached_floor_area.len();
 
     // Use fixed starting Y coordinate based on maximum ground level when terrain is enabled
@@ -121,7 +122,8 @@ pub fn generate_buildings(
     let mut processed_points: HashSet<(i32, i32)> = HashSet::new();
     let mut building_height: i32 = ((6.0 * scale_factor) as i32).max(3); // Default building height with scale and minimum
     let mut is_tall_building = false;
-    let mut rng = rand::thread_rng();
+    // Use deterministic RNG seeded by element ID for consistent results across region boundaries
+    let mut rng = element_rng(element.id);
     let use_vertical_windows = rng.gen_bool(0.7);
     let use_accent_roof_line = rng.gen_bool(0.25);
 
@@ -386,7 +388,7 @@ pub fn generate_buildings(
                 building_height = ((23.0 * scale_factor) as i32).max(3);
             }
         } else if building_type == "bridge" {
-            generate_bridge(editor, element, args.timeout.as_ref());
+            generate_bridge(editor, element, flood_fill_cache, args.timeout.as_ref());
             return;
         }
     }
@@ -1484,6 +1486,7 @@ pub fn generate_building_from_relation(
     editor: &mut WorldEditor,
     relation: &ProcessedRelation,
     args: &Args,
+    flood_fill_cache: &FloodFillCache,
 ) {
     // Extract levels from relation tags
     let relation_levels = relation
@@ -1495,7 +1498,13 @@ pub fn generate_building_from_relation(
     // Process the outer way to create the building walls
     for member in &relation.members {
         if member.role == ProcessedMemberRole::Outer {
-            generate_buildings(editor, &member.way, args, Some(relation_levels));
+            generate_buildings(
+                editor,
+                &member.way,
+                args,
+                Some(relation_levels),
+                flood_fill_cache,
+            );
         }
     }
 
@@ -1519,28 +1528,29 @@ pub fn generate_building_from_relation(
 fn generate_bridge(
     editor: &mut WorldEditor,
     element: &ProcessedWay,
+    flood_fill_cache: &FloodFillCache,
     floodfill_timeout: Option<&Duration>,
 ) {
     let floor_block: Block = STONE;
     let railing_block: Block = STONE_BRICKS;
 
+    // Calculate bridge level based on the "level" tag (computed once, used throughout)
+    let bridge_y_offset = if let Some(level_str) = element.tags.get("level") {
+        if let Ok(level) = level_str.parse::<i32>() {
+            (level * 3) + 1
+        } else {
+            1 // Default elevation
+        }
+    } else {
+        1 // Default elevation
+    };
+
     // Process the nodes to create bridge pathways and railings
     let mut previous_node: Option<(i32, i32)> = None;
     for node in &element.nodes {
         let x: i32 = node.x;
         let z: i32 = node.z;
 
-        // Calculate bridge level based on the "level" tag
-        let bridge_y_offset = if let Some(level_str) = element.tags.get("level") {
-            if let Ok(level) = level_str.parse::<i32>() {
-                (level * 3) + 1
-            } else {
-                1 // Default elevation
-            }
-        } else {
-            1 // Default elevation
-        };
-
         // Create bridge path using Bresenham's line
         if let Some(prev) = previous_node {
             let bridge_points: Vec<(i32, i32, i32)> =
@@ -1556,21 +1566,8 @@ fn generate_bridge(
         previous_node = Some((x, z));
     }
 
-    // Flood fill the area between the bridge path nodes
-    let polygon_coords: Vec<(i32, i32)> = element.nodes.iter().map(|n| (n.x, n.z)).collect();
-
-    let bridge_area: Vec<(i32, i32)> = flood_fill_area(&polygon_coords, floodfill_timeout);
-
-    // Calculate bridge level based on the "level" tag
-    let bridge_y_offset = if let Some(level_str) = element.tags.get("level") {
-        if let Ok(level) = level_str.parse::<i32>() {
-            (level * 3) + 1
-        } else {
-            1 // Default elevation
-        }
-    } else {
-        1 // Default elevation
-    };
+    // Flood fill the area between the bridge path nodes (uses cache)
+    let bridge_area: Vec<(i32, i32)> = flood_fill_cache.get_or_compute(element, floodfill_timeout);
 
     // Place floor blocks
     for (x, z) in bridge_area {

src/element_processing/highways.rs

@@ -2,11 +2,82 @@ use crate::args::Args;
 use crate::block_definitions::*;
 use crate::bresenham::bresenham_line;
 use crate::coordinate_system::cartesian::XZPoint;
-use crate::floodfill::flood_fill_area;
+use crate::floodfill_cache::FloodFillCache;
 use crate::osm_parser::{ProcessedElement, ProcessedWay};
 use crate::world_editor::WorldEditor;
+use rayon::prelude::*;
+use std::collections::HashMap;
 
-pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, args: &Args) {
+/// Type alias for highway connectivity map
+pub type HighwayConnectivityMap = HashMap<(i32, i32), Vec<i32>>;
+
+/// Generates highways with elevation support based on layer tags and connectivity analysis
+pub fn generate_highways(
+    editor: &mut WorldEditor,
+    element: &ProcessedElement,
+    args: &Args,
+    highway_connectivity: &HighwayConnectivityMap,
+    flood_fill_cache: &FloodFillCache,
+) {
+    generate_highways_internal(
+        editor,
+        element,
+        args,
+        highway_connectivity,
+        flood_fill_cache,
+    );
+}
+
+/// Build a connectivity map for highway endpoints to determine where slopes are needed.
+/// Uses parallel processing for better performance on large element sets.
+pub fn build_highway_connectivity_map(elements: &[ProcessedElement]) -> HighwayConnectivityMap {
+    // Parallel map phase: extract connectivity data from each highway element
+    let partial_maps: Vec<Vec<((i32, i32), i32)>> = elements
+        .par_iter()
+        .filter_map(|element| {
+            if let ProcessedElement::Way(way) = element {
+                if way.tags.contains_key("highway") && !way.nodes.is_empty() {
+                    let layer_value = way
+                        .tags
+                        .get("layer")
+                        .and_then(|layer| layer.parse::<i32>().ok())
+                        .unwrap_or(0);
+
+                    // Treat negative layers as ground level (0) for connectivity
+                    let layer_value = if layer_value < 0 { 0 } else { layer_value };
+
+                    let start_node = &way.nodes[0];
+                    let end_node = &way.nodes[way.nodes.len() - 1];
+
+                    let start_coord = (start_node.x, start_node.z);
+                    let end_coord = (end_node.x, end_node.z);
+
+                    return Some(vec![(start_coord, layer_value), (end_coord, layer_value)]);
+                }
+            }
+            None
+        })
+        .collect();
+
+    // Sequential reduce phase: merge all partial results into final map
+    let mut connectivity_map: HashMap<(i32, i32), Vec<i32>> = HashMap::new();
+    for entries in partial_maps {
+        for (coord, layer) in entries {
+            connectivity_map.entry(coord).or_default().push(layer);
+        }
+    }
+
+    connectivity_map
+}
+
+/// Internal function that generates highways with connectivity context for elevation handling
+fn generate_highways_internal(
+    editor: &mut WorldEditor,
+    element: &ProcessedElement,
+    args: &Args,
+    highway_connectivity: &HashMap<(i32, i32), Vec<i32>>, // Maps node coordinates to list of layers that connect to this node
+    flood_fill_cache: &FloodFillCache,
+) {
     if let Some(highway_type) = element.tags().get("highway") {
         if highway_type == "street_lamp" {
             // Handle street lamps
@@ -77,14 +148,9 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                 };
             }
 
-            // Fill the area using flood fill or by iterating through the nodes
-            let polygon_coords: Vec<(i32, i32)> = way
-                .nodes
-                .iter()
-                .map(|n: &crate::osm_parser::ProcessedNode| (n.x, n.z))
-                .collect();
+            // Fill the area using flood fill cache
             let filled_area: Vec<(i32, i32)> =
-                flood_fill_area(&polygon_coords, args.timeout.as_ref());
+                flood_fill_cache.get_or_compute(way, args.timeout.as_ref());
 
             for (x, z) in filled_area {
                 editor.set_block(surface_block, x, 0, z, None, None);
@@ -97,13 +163,17 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
             let mut add_outline = false;
             let scale_factor = args.scale;
 
-            // Skip if 'layer' or 'level' is negative in the tags
-            if let Some(layer) = element.tags().get("layer") {
-                if layer.parse::<i32>().unwrap_or(0) < 0 {
-                    return;
-                }
-            }
+            // Parse the layer value for elevation calculation
+            let layer_value = element
+                .tags()
+                .get("layer")
+                .and_then(|layer| layer.parse::<i32>().ok())
+                .unwrap_or(0);
 
+            // Treat negative layers as ground level (0)
+            let layer_value = if layer_value < 0 { 0 } else { layer_value };
+
+            // Skip if 'level' is negative in the tags (indoor mapping)
             if let Some(level) = element.tags().get("level") {
                 if level.parse::<i32>().unwrap_or(0) < 0 {
                     return;
@@ -120,10 +190,14 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                     block_type = DIRT_PATH;
                     block_range = 1;
                 }
-                "motorway" | "primary" => {
+                "motorway" | "primary" | "trunk" => {
                     block_range = 5;
                     add_stripe = true;
                 }
+                "secondary" => {
+                    block_range = 4;
+                    add_stripe = true;
+                }
                 "tertiary" => {
                     add_stripe = true;
                 }
@@ -173,7 +247,40 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                 block_range = ((block_range as f64) * scale_factor).floor() as i32;
             }
 
+            // Calculate elevation based on layer
+            const LAYER_HEIGHT_STEP: i32 = 6; // Each layer is 6 blocks higher/lower
+            let base_elevation = layer_value * LAYER_HEIGHT_STEP;
+
+            // Check if we need slopes at start and end
+            let needs_start_slope =
+                should_add_slope_at_node(&way.nodes[0], layer_value, highway_connectivity);
+            let needs_end_slope = should_add_slope_at_node(
+                &way.nodes[way.nodes.len() - 1],
+                layer_value,
+                highway_connectivity,
+            );
+
+            // Calculate total way length for slope distribution
+            let total_way_length = calculate_way_length(way);
+
+            // Check if this is a short isolated elevated segment - if so, treat as ground level
+            let is_short_isolated_elevated =
+                needs_start_slope && needs_end_slope && layer_value > 0 && total_way_length <= 35;
+
+            // Override elevation and slopes for short isolated segments
+            let (effective_elevation, effective_start_slope, effective_end_slope) =
+                if is_short_isolated_elevated {
+                    (0, false, false) // Treat as ground level
+                } else {
+                    (base_elevation, needs_start_slope, needs_end_slope)
+                };
+
+            let slope_length = (total_way_length as f32 * 0.35).clamp(15.0, 50.0) as usize; // 35% of way length, max 50 blocks, min 15 blocks
+
             // Iterate over nodes to create the highway
+            let mut segment_index = 0;
+            let total_segments = way.nodes.len() - 1;
+
             for node in &way.nodes {
                 if let Some(prev) = previous_node {
                     let (x1, z1) = prev;
@@ -181,17 +288,30 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                     let z2: i32 = node.z;
 
                     // Generate the line of coordinates between the two nodes
-                    // we don't care about the y because it's going to get overwritten
-                    // I'm not sure if we'll keep it this way
                     let bresenham_points: Vec<(i32, i32, i32)> =
                         bresenham_line(x1, 0, z1, x2, 0, z2);
 
+                    // Calculate elevation for this segment
+                    let segment_length = bresenham_points.len();
+
                     // Variables to manage dashed line pattern
                     let mut stripe_length: i32 = 0;
-                    let dash_length: i32 = (5.0 * scale_factor).ceil() as i32; // Length of the solid part of the stripe
-                    let gap_length: i32 = (5.0 * scale_factor).ceil() as i32; // Length of the gap part of the stripe
+                    let dash_length: i32 = (5.0 * scale_factor).ceil() as i32;
+                    let gap_length: i32 = (5.0 * scale_factor).ceil() as i32;
+
+                    for (point_index, (x, _, z)) in bresenham_points.iter().enumerate() {
+                        // Calculate Y elevation for this point based on slopes and layer
+                        let current_y = calculate_point_elevation(
+                            segment_index,
+                            point_index,
+                            segment_length,
+                            total_segments,
+                            effective_elevation,
+                            effective_start_slope,
+                            effective_end_slope,
+                            slope_length,
+                        );
 
-                    for (x, _, z) in bresenham_points {
                         // Draw the road surface for the entire width
                         for dx in -block_range..=block_range {
                             for dz in -block_range..=block_range {
@@ -209,7 +329,7 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                             editor.set_block(
                                                 WHITE_CONCRETE,
                                                 set_x,
-                                                0,
+                                                current_y,
                                                 set_z,
                                                 Some(&[BLACK_CONCRETE]),
                                                 None,
@@ -218,7 +338,7 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                             editor.set_block(
                                                 BLACK_CONCRETE,
                                                 set_x,
-                                                0,
+                                                current_y,
                                                 set_z,
                                                 None,
                                                 None,
@@ -228,7 +348,7 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                         editor.set_block(
                                             WHITE_CONCRETE,
                                             set_x,
-                                            0,
+                                            current_y,
                                             set_z,
                                             Some(&[BLACK_CONCRETE]),
                                             None,
@@ -237,7 +357,7 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                         editor.set_block(
                                             BLACK_CONCRETE,
                                             set_x,
-                                            0,
+                                            current_y,
                                             set_z,
                                             None,
                                             None,
@@ -247,12 +367,38 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                     editor.set_block(
                                         block_type,
                                         set_x,
-                                        0,
+                                        current_y,
                                         set_z,
                                         None,
                                         Some(&[BLACK_CONCRETE, WHITE_CONCRETE]),
                                     );
                                 }
+
+                                // Add stone brick foundation underneath elevated highways for thickness
+                                if effective_elevation > 0 && current_y > 0 {
+                                    // Add 1 layer of stone bricks underneath the highway surface
+                                    editor.set_block(
+                                        STONE_BRICKS,
+                                        set_x,
+                                        current_y - 1,
+                                        set_z,
+                                        None,
+                                        None,
+                                    );
+                                }
+
+                                // Add support pillars for elevated highways
+                                if effective_elevation != 0 && current_y > 0 {
+                                    add_highway_support_pillar(
+                                        editor,
+                                        set_x,
+                                        current_y,
+                                        set_z,
+                                        dx,
+                                        dz,
+                                        block_range,
+                                    );
+                                }
                             }
                         }
 
@@ -265,7 +411,7 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                 editor.set_block(
                                     LIGHT_GRAY_CONCRETE,
                                     outline_x,
-                                    0,
+                                    current_y,
                                     outline_z,
                                     None,
                                     None,
@@ -278,7 +424,7 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                                 editor.set_block(
                                     LIGHT_GRAY_CONCRETE,
                                     outline_x,
-                                    0,
+                                    current_y,
                                     outline_z,
                                     None,
                                     None,
@@ -289,12 +435,12 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                         // Add a dashed white line in the middle for larger roads
                         if add_stripe {
                             if stripe_length < dash_length {
-                                let stripe_x: i32 = x;
-                                let stripe_z: i32 = z;
+                                let stripe_x: i32 = *x;
+                                let stripe_z: i32 = *z;
                                 editor.set_block(
                                     WHITE_CONCRETE,
                                     stripe_x,
-                                    0,
+                                    current_y,
                                     stripe_z,
                                     Some(&[BLACK_CONCRETE]),
                                     None,
@@ -308,6 +454,8 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
                             }
                         }
                     }
+
+                    segment_index += 1;
                 }
                 previous_node = Some((node.x, node.z));
             }
@@ -315,6 +463,131 @@ pub fn generate_highways(editor: &mut WorldEditor, element: &ProcessedElement, a
     }
 }
 
+/// Helper function to determine if a slope should be added at a specific node
+fn should_add_slope_at_node(
+    node: &crate::osm_parser::ProcessedNode,
+    current_layer: i32,
+    highway_connectivity: &HashMap<(i32, i32), Vec<i32>>,
+) -> bool {
+    let node_coord = (node.x, node.z);
+
+    // If we don't have connectivity information, always add slopes for non-zero layers
+    if highway_connectivity.is_empty() {
+        return current_layer != 0;
+    }
+
+    // Check if there are other highways at different layers connected to this node
+    if let Some(connected_layers) = highway_connectivity.get(&node_coord) {
+        // Count how many ways are at the same layer as current way
+        let same_layer_count = connected_layers
+            .iter()
+            .filter(|&&layer| layer == current_layer)
+            .count();
+
+        // If this is the only way at this layer connecting to this node, we need a slope
+        // (unless we're at ground level and connecting to ground level ways)
+        if same_layer_count <= 1 {
+            return current_layer != 0;
+        }
+
+        // If there are multiple ways at the same layer, don't add slope
+        false
+    } else {
+        // No other highways connected, add slope if not at ground level
+        current_layer != 0
+    }
+}
+
+/// Helper function to calculate the total length of a way in blocks
+fn calculate_way_length(way: &ProcessedWay) -> usize {
+    let mut total_length = 0;
+    let mut previous_node: Option<&crate::osm_parser::ProcessedNode> = None;
+
+    for node in &way.nodes {
+        if let Some(prev) = previous_node {
+            let dx = (node.x - prev.x).abs();
+            let dz = (node.z - prev.z).abs();
+            total_length += ((dx * dx + dz * dz) as f32).sqrt() as usize;
+        }
+        previous_node = Some(node);
+    }
+
+    total_length
+}
+
+/// Calculate the Y elevation for a specific point along the highway
+#[allow(clippy::too_many_arguments)]
+fn calculate_point_elevation(
+    segment_index: usize,
+    point_index: usize,
+    segment_length: usize,
+    total_segments: usize,
+    base_elevation: i32,
+    needs_start_slope: bool,
+    needs_end_slope: bool,
+    slope_length: usize,
+) -> i32 {
+    // If no slopes needed, return base elevation
+    if !needs_start_slope && !needs_end_slope {
+        return base_elevation;
+    }
+
+    // Calculate total distance from start
+    let total_distance_from_start = segment_index * segment_length + point_index;
+    let total_way_length = total_segments * segment_length;
+
+    // Ensure we have reasonable values
+    if total_way_length == 0 || slope_length == 0 {
+        return base_elevation;
+    }
+
+    // Start slope calculation - gradual rise from ground level
+    if needs_start_slope && total_distance_from_start <= slope_length {
+        let slope_progress = total_distance_from_start as f32 / slope_length as f32;
+        let elevation_offset = (base_elevation as f32 * slope_progress) as i32;
+        return elevation_offset;
+    }
+
+    // End slope calculation - gradual descent to ground level
+    if needs_end_slope
+        && total_distance_from_start >= (total_way_length.saturating_sub(slope_length))
+    {
+        let distance_from_end = total_way_length - total_distance_from_start;
+        let slope_progress = distance_from_end as f32 / slope_length as f32;
+        let elevation_offset = (base_elevation as f32 * slope_progress) as i32;
+        return elevation_offset;
+    }
+
+    // Middle section at full elevation
+    base_elevation
+}
+
+/// Add support pillars for elevated highways
+fn add_highway_support_pillar(
+    editor: &mut WorldEditor,
+    x: i32,
+    highway_y: i32,
+    z: i32,
+    dx: i32,
+    dz: i32,
+    _block_range: i32, // Keep for future use
+) {
+    // Only add pillars at specific intervals and positions
+    if dx == 0 && dz == 0 && (x + z) % 8 == 0 {
+        // Add pillar from ground to highway level
+        for y in 1..highway_y {
+            editor.set_block(STONE_BRICKS, x, y, z, None, None);
+        }
+
+        // Add pillar base
+        for base_dx in -1..=1 {
+            for base_dz in -1..=1 {
+                editor.set_block(STONE_BRICKS, x + base_dx, 0, z + base_dz, None, None);
+            }
+        }
+    }
+}
+
 /// Generates a siding using stone brick slabs
 pub fn generate_siding(editor: &mut WorldEditor, element: &ProcessedWay) {
     let mut previous_node: Option<XZPoint> = None;

src/element_processing/landuse.rs

@@ -1,12 +1,18 @@
 use crate::args::Args;
 use crate::block_definitions::*;
+use crate::deterministic_rng::element_rng;
 use crate::element_processing::tree::Tree;
-use crate::floodfill::flood_fill_area;
+use crate::floodfill_cache::FloodFillCache;
 use crate::osm_parser::{ProcessedMemberRole, ProcessedRelation, ProcessedWay};
 use crate::world_editor::WorldEditor;
 use rand::Rng;
 
-pub fn generate_landuse(editor: &mut WorldEditor, element: &ProcessedWay, args: &Args) {
+pub fn generate_landuse(
+    editor: &mut WorldEditor,
+    element: &ProcessedWay,
+    args: &Args,
+    flood_fill_cache: &FloodFillCache,
+) {
     // Determine block type based on landuse tag
     let binding: String = "".to_string();
     let landuse_tag: &String = element.tags.get("landuse").unwrap_or(&binding);
@@ -44,11 +50,12 @@ pub fn generate_landuse(editor: &mut WorldEditor, element: &ProcessedWay, args:
         _ => GRASS_BLOCK,
     };
 
-    // Get the area of the landuse element
-    let polygon_coords: Vec<(i32, i32)> = element.nodes.iter().map(|n| (n.x, n.z)).collect();
-    let floor_area: Vec<(i32, i32)> = flood_fill_area(&polygon_coords, args.timeout.as_ref());
+    // Get the area of the landuse element using cache
+    let floor_area: Vec<(i32, i32)> =
+        flood_fill_cache.get_or_compute(element, args.timeout.as_ref());
 
-    let mut rng: rand::prelude::ThreadRng = rand::thread_rng();
+    // Use deterministic RNG seeded by element ID for consistent results across region boundaries
+    let mut rng = element_rng(element.id);
 
     for (x, z) in floor_area {
         if landuse_tag == "traffic_island" {
@@ -275,12 +282,13 @@ pub fn generate_landuse_from_relation(
     editor: &mut WorldEditor,
     rel: &ProcessedRelation,
     args: &Args,
+    flood_fill_cache: &FloodFillCache,
 ) {
     if rel.tags.contains_key("landuse") {
         // Generate individual ways with their original tags
         for member in &rel.members {
             if member.role == ProcessedMemberRole::Outer {
-                generate_landuse(editor, &member.way.clone(), args);
+                generate_landuse(editor, &member.way.clone(), args, flood_fill_cache);
             }
         }
 
@@ -302,7 +310,7 @@ pub fn generate_landuse_from_relation(
             };
 
             // Generate landuse area from combined way
-            generate_landuse(editor, &combined_way, args);
+            generate_landuse(editor, &combined_way, args, flood_fill_cache);
         }
     }
 }

src/element_processing/leisure.rs

@@ -1,13 +1,19 @@
 use crate::args::Args;
 use crate::block_definitions::*;
 use crate::bresenham::bresenham_line;
+use crate::deterministic_rng::element_rng;
 use crate::element_processing::tree::Tree;
-use crate::floodfill::flood_fill_area;
+use crate::floodfill_cache::FloodFillCache;
 use crate::osm_parser::{ProcessedMemberRole, ProcessedRelation, ProcessedWay};
 use crate::world_editor::WorldEditor;
 use rand::Rng;
 
-pub fn generate_leisure(editor: &mut WorldEditor, element: &ProcessedWay, args: &Args) {
+pub fn generate_leisure(
+    editor: &mut WorldEditor,
+    element: &ProcessedWay,
+    args: &Args,
+    flood_fill_cache: &FloodFillCache,
+) {
     if let Some(leisure_type) = element.tags.get("leisure") {
         let mut previous_node: Option<(i32, i32)> = None;
         let mut corner_addup: (i32, i32, i32) = (0, 0, 0);
@@ -18,6 +24,7 @@ pub fn generate_leisure(editor: &mut WorldEditor, element: &ProcessedWay, args:
             "park" | "nature_reserve" | "garden" | "disc_golf_course" | "golf_course" => {
                 GRASS_BLOCK
             }
+            "schoolyard" => BLACK_CONCRETE,
             "playground" | "recreation_ground" | "pitch" | "beach_resort" | "dog_park" => {
                 if let Some(surface) = element.tags.get("surface") {
                     match surface.as_str() {
@@ -73,15 +80,13 @@ pub fn generate_leisure(editor: &mut WorldEditor, element: &ProcessedWay, args:
             previous_node = Some((node.x, node.z));
         }
 
-        // Flood-fill the interior of the leisure area
+        // Flood-fill the interior of the leisure area using cache
         if corner_addup != (0, 0, 0) {
-            let polygon_coords: Vec<(i32, i32)> = element
-                .nodes
-                .iter()
-                .map(|n: &crate::osm_parser::ProcessedNode| (n.x, n.z))
-                .collect();
             let filled_area: Vec<(i32, i32)> =
-                flood_fill_area(&polygon_coords, args.timeout.as_ref());
+                flood_fill_cache.get_or_compute(element, args.timeout.as_ref());
+
+            // Use deterministic RNG seeded by element ID for consistent results across region boundaries
+            let mut rng = element_rng(element.id);
 
             for (x, z) in filled_area {
                 editor.set_block(block_type, x, 0, z, Some(&[GRASS_BLOCK]), None);
@@ -90,7 +95,6 @@ pub fn generate_leisure(editor: &mut WorldEditor, element: &ProcessedWay, args:
                 if matches!(leisure_type.as_str(), "park" | "garden" | "nature_reserve")
                     && editor.check_for_block(x, 0, z, Some(&[GRASS_BLOCK]))
                 {
-                    let mut rng: rand::prelude::ThreadRng = rand::thread_rng();
                     let random_choice: i32 = rng.gen_range(0..1000);
 
                     match random_choice {
@@ -122,7 +126,6 @@ pub fn generate_leisure(editor: &mut WorldEditor, element: &ProcessedWay, args:
 
                 // Add playground or recreation ground features
                 if matches!(leisure_type.as_str(), "playground" | "recreation_ground") {
-                    let mut rng: rand::prelude::ThreadRng = rand::thread_rng();
                     let random_choice: i32 = rng.gen_range(0..5000);
 
                     match random_choice {
@@ -175,12 +178,13 @@ pub fn generate_leisure_from_relation(
     editor: &mut WorldEditor,
     rel: &ProcessedRelation,
     args: &Args,
+    flood_fill_cache: &FloodFillCache,
 ) {
     if rel.tags.get("leisure") == Some(&"park".to_string()) {
         // First generate individual ways with their original tags
         for member in &rel.members {
             if member.role == ProcessedMemberRole::Outer {
-                generate_leisure(editor, &member.way, args);
+                generate_leisure(editor, &member.way, args, flood_fill_cache);
             }
         }
 
@@ -200,6 +204,6 @@ pub fn generate_leisure_from_relation(
         };
 
         // Generate leisure area from combined way
-        generate_leisure(editor, &combined_way, args);
+        generate_leisure(editor, &combined_way, args, flood_fill_cache);
     }
 }

src/element_processing/man_made.rs

@@ -25,6 +25,7 @@ pub fn generate_man_made(editor: &mut WorldEditor, element: &ProcessedElement, _
             "chimney" => generate_chimney(editor, element),
             "water_well" => generate_water_well(editor, element),
             "water_tower" => generate_water_tower(editor, element),
+            "mast" => generate_antenna(editor, element),
             _ => {} // Unknown man_made type, ignore
         }
     }
@@ -96,7 +97,6 @@ fn generate_antenna(editor: &mut WorldEditor, element: &ProcessedElement) {
             Some(h) => h.parse::<i32>().unwrap_or(20).min(40), // Max 40 blocks
             None => match element.tags().get("tower:type").map(|s| s.as_str()) {
                 Some("communication") => 20,
-                Some("transmission") => 25,
                 Some("cellular") => 15,
                 _ => 20,
             },
@@ -249,6 +249,7 @@ pub fn generate_man_made_nodes(editor: &mut WorldEditor, node: &ProcessedNode) {
             "chimney" => generate_chimney(editor, &element),
             "water_well" => generate_water_well(editor, &element),
             "water_tower" => generate_water_tower(editor, &element),
+            "mast" => generate_antenna(editor, &element),
             _ => {} // Unknown man_made type, ignore
         }
     }

src/element_processing/natural.rs

@@ -1,13 +1,19 @@
 use crate::args::Args;
 use crate::block_definitions::*;
 use crate::bresenham::bresenham_line;
+use crate::deterministic_rng::element_rng;
 use crate::element_processing::tree::Tree;
-use crate::floodfill::flood_fill_area;
+use crate::floodfill_cache::FloodFillCache;
 use crate::osm_parser::{ProcessedElement, ProcessedMemberRole, ProcessedRelation, ProcessedWay};
 use crate::world_editor::WorldEditor;
 use rand::Rng;
 
-pub fn generate_natural(editor: &mut WorldEditor, element: &ProcessedElement, args: &Args) {
+pub fn generate_natural(
+    editor: &mut WorldEditor,
+    element: &ProcessedElement,
+    args: &Args,
+    flood_fill_cache: &FloodFillCache,
+) {
     if let Some(natural_type) = element.tags().get("natural") {
         if natural_type == "tree" {
             if let ProcessedElement::Node(node) = element {
@@ -69,17 +75,13 @@ pub fn generate_natural(editor: &mut WorldEditor, element: &ProcessedElement, ar
                 previous_node = Some((x, z));
             }
 
-            // If there are natural nodes, flood-fill the area
+            // If there are natural nodes, flood-fill the area using cache
             if corner_addup != (0, 0, 0) {
-                let polygon_coords: Vec<(i32, i32)> = way
-                    .nodes
-                    .iter()
-                    .map(|n: &crate::osm_parser::ProcessedNode| (n.x, n.z))
-                    .collect();
                 let filled_area: Vec<(i32, i32)> =
-                    flood_fill_area(&polygon_coords, args.timeout.as_ref());
+                    flood_fill_cache.get_or_compute(way, args.timeout.as_ref());
 
-                let mut rng: rand::prelude::ThreadRng = rand::thread_rng();
+                // Use deterministic RNG seeded by element ID for consistent results across region boundaries
+                let mut rng = element_rng(way.id);
 
                 for (x, z) in filled_area {
                     editor.set_block(block_type, x, 0, z, None, None);
@@ -448,12 +450,18 @@ pub fn generate_natural_from_relation(
     editor: &mut WorldEditor,
     rel: &ProcessedRelation,
     args: &Args,
+    flood_fill_cache: &FloodFillCache,
 ) {
     if rel.tags.contains_key("natural") {
         // Generate individual ways with their original tags
         for member in &rel.members {
             if member.role == ProcessedMemberRole::Outer {
-                generate_natural(editor, &ProcessedElement::Way(member.way.clone()), args);
+                generate_natural(
+                    editor,
+                    &ProcessedElement::Way((*member.way).clone()),
+                    args,
+                    flood_fill_cache,
+                );
             }
         }
 
@@ -475,7 +483,12 @@ pub fn generate_natural_from_relation(
             };
 
             // Generate natural area from combined way
-            generate_natural(editor, &ProcessedElement::Way(combined_way), args);
+            generate_natural(
+                editor,
+                &ProcessedElement::Way(combined_way),
+                args,
+                flood_fill_cache,
+            );
         }
     }
 }

src/element_processing/railways.rs

@@ -174,3 +174,71 @@ fn determine_rail_direction(
         (None, None) => RAIL_NORTH_SOUTH,
     }
 }
+
+pub fn generate_roller_coaster(editor: &mut WorldEditor, element: &ProcessedWay) {
+    if let Some(roller_coaster) = element.tags.get("roller_coaster") {
+        if roller_coaster == "track" {
+            // Check if it's indoor (skip if yes)
+            if let Some(indoor) = element.tags.get("indoor") {
+                if indoor == "yes" {
+                    return;
+                }
+            }
+
+            // Check if layer is negative (skip if yes)
+            if let Some(layer) = element.tags.get("layer") {
+                if let Ok(layer_value) = layer.parse::<i32>() {
+                    if layer_value < 0 {
+                        return;
+                    }
+                }
+            }
+
+            let elevation_height = 4; // 4 blocks in the air
+            let pillar_interval = 6; // Support pillars every 6 blocks
+
+            for i in 1..element.nodes.len() {
+                let prev_node = element.nodes[i - 1].xz();
+                let cur_node = element.nodes[i].xz();
+
+                let points = bresenham_line(prev_node.x, 0, prev_node.z, cur_node.x, 0, cur_node.z);
+                let smoothed_points = smooth_diagonal_rails(&points);
+
+                for j in 0..smoothed_points.len() {
+                    let (bx, _, bz) = smoothed_points[j];
+
+                    // Place track foundation at elevation height
+                    editor.set_block(IRON_BLOCK, bx, elevation_height, bz, None, None);
+
+                    let prev = if j > 0 {
+                        Some(smoothed_points[j - 1])
+                    } else {
+                        None
+                    };
+                    let next = if j < smoothed_points.len() - 1 {
+                        Some(smoothed_points[j + 1])
+                    } else {
+                        None
+                    };
+
+                    let rail_block = determine_rail_direction(
+                        (bx, bz),
+                        prev.map(|(x, _, z)| (x, z)),
+                        next.map(|(x, _, z)| (x, z)),
+                    );
+
+                    // Place rail on top of the foundation
+                    editor.set_block(rail_block, bx, elevation_height + 1, bz, None, None);
+
+                    // Place support pillars every pillar_interval blocks
+                    if bx % pillar_interval == 0 && bz % pillar_interval == 0 {
+                        // Create a pillar from ground level up to the track
+                        for y in 1..elevation_height {
+                            editor.set_block(IRON_BLOCK, bx, y, bz, None, None);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

src/element_processing/subprocessor/buildings_interior.rs

@@ -133,7 +133,7 @@ pub fn get_interior_block(c: char, is_layer2: bool, wall_block: Block) -> Option
         '6' => Some(RED_BED_SOUTH_FOOT), // Bed South Foot
         '7' => Some(RED_BED_WEST_HEAD),  // Bed West Head
         '8' => Some(RED_BED_WEST_FOOT),  // Bed West Foot
-        'H' => Some(CHEST),              // Chest
+        // 'H' => Some(CHEST),           // Chest
         'L' => Some(CAULDRON),           // Cauldron
         'A' => Some(ANVIL),              // Anvil
         'P' => Some(OAK_PRESSURE_PLATE), // Pressure Plate
@@ -145,7 +145,7 @@ pub fn get_interior_block(c: char, is_layer2: bool, wall_block: Block) -> Option
                 Some(DARK_OAK_DOOR_LOWER)
             }
         }
-        'J' => Some(JUKEBOX),       // Jukebox
+        'J' => Some(NOTE_BLOCK),    // Note block
         'G' => Some(GLOWSTONE),     // Glowstone
         'N' => Some(BREWING_STAND), // Brewing Stand
         'T' => Some(WHITE_CARPET),  // White Carpet

src/element_processing/tree.rs

@@ -1,4 +1,5 @@
 use crate::block_definitions::*;
+use crate::deterministic_rng::coord_rng;
 use crate::world_editor::WorldEditor;
 use rand::Rng;
 
@@ -115,7 +116,9 @@ impl Tree<'_> {
         blacklist.extend(Self::get_functional_blocks());
         blacklist.push(WATER);
 
-        let mut rng = rand::thread_rng();
+        // Use deterministic RNG based on coordinates for consistent tree types across region boundaries
+        // The element_id of 0 is used as a salt for tree-specific randomness
+        let mut rng = coord_rng(x, z, 0);
 
         let tree = Self::get_tree(match rng.gen_range(1..=3) {
             1 => TreeType::Oak,
@@ -307,7 +310,7 @@ impl Tree<'_> {
             FURNACE,
             ANVIL,
             BREWING_STAND,
-            JUKEBOX,
+            NOTE_BLOCK,
             BOOKSHELF,
             CAULDRON,
             // Beds

src/element_processing/water_areas.rs

@@ -1,19 +1,40 @@
+use geo::orient::{Direction, Orient};
 use geo::{Contains, Intersects, LineString, Point, Polygon, Rect};
-use std::time::Instant;
 
+use crate::clipping::clip_water_ring_to_bbox;
 use crate::{
     block_definitions::WATER,
-    coordinate_system::cartesian::XZPoint,
-    osm_parser::{ProcessedMemberRole, ProcessedNode, ProcessedRelation},
+    coordinate_system::cartesian::{XZBBox, XZPoint},
+    osm_parser::{ProcessedMemberRole, ProcessedNode, ProcessedRelation, ProcessedWay},
     world_editor::WorldEditor,
 };
 
-pub fn generate_water_areas(editor: &mut WorldEditor, element: &ProcessedRelation) {
-    let start_time = Instant::now();
+pub fn generate_water_area_from_way(
+    editor: &mut WorldEditor,
+    element: &ProcessedWay,
+    _xzbbox: &XZBBox,
+) {
+    let outers = [element.nodes.clone()];
+    if !verify_closed_rings(&outers) {
+        println!("Skipping way {} due to invalid polygon", element.id);
+        return;
+    }
 
+    generate_water_areas(editor, &outers, &[]);
+}
+
+pub fn generate_water_areas_from_relation(
+    editor: &mut WorldEditor,
+    element: &ProcessedRelation,
+    xzbbox: &XZBBox,
+) {
     // Check if this is a water relation (either with water tag or natural=water)
     let is_water = element.tags.contains_key("water")
-        || element.tags.get("natural") == Some(&"water".to_string());
+        || element
+            .tags
+            .get("natural")
+            .map(|val| val == "water" || val == "bay")
+            .unwrap_or(false);
 
     if !is_water {
         return;
@@ -36,79 +57,132 @@ pub fn generate_water_areas(editor: &mut WorldEditor, element: &ProcessedRelatio
         }
     }
 
-    // Process each outer polygon individually
-    for (i, outer_nodes) in outers.iter().enumerate() {
-        let mut individual_outers = vec![outer_nodes.clone()];
+    // Preserve OSM-defined outer/inner roles without modification
+    merge_way_segments(&mut outers);
 
-        merge_loopy_loops(&mut individual_outers);
-        if !verify_loopy_loops(&individual_outers) {
-            println!(
-                "Skipping invalid outer polygon {} for relation {}",
-                i + 1,
-                element.id
-            );
-            continue; // Skip this outer if it's not valid
+    // Clip assembled rings to bbox (must happen after merging to preserve ring connectivity)
+    outers = outers
+        .into_iter()
+        .filter_map(|ring| clip_water_ring_to_bbox(&ring, xzbbox))
+        .collect();
+    merge_way_segments(&mut inners);
+    inners = inners
+        .into_iter()
+        .filter_map(|ring| clip_water_ring_to_bbox(&ring, xzbbox))
+        .collect();
+
+    if !verify_closed_rings(&outers) {
+        // For clipped multipolygons, some loops may not close perfectly
+        // Instead of force-closing with straight lines (which creates wedges),
+        // filter out unclosed loops and only render the properly closed ones
+
+        // Filter: Keep only loops that are already closed OR can be closed within 1 block
+        outers.retain(|loop_nodes| {
+            if loop_nodes.len() < 3 {
+                return false;
+            }
+            let first = &loop_nodes[0];
+            let last = loop_nodes.last().unwrap();
+            let dx = (first.x - last.x).abs();
+            let dz = (first.z - last.z).abs();
+
+            // Keep if already closed by ID or endpoints are within 1 block
+            first.id == last.id || (dx <= 1 && dz <= 1)
+        });
+
+        // Now close the remaining loops that are within 1 block tolerance
+        for loop_nodes in outers.iter_mut() {
+            let first = loop_nodes[0].clone();
+            let last_idx = loop_nodes.len() - 1;
+            if loop_nodes[0].id != loop_nodes[last_idx].id {
+                // Endpoints are close (within tolerance), close the loop
+                loop_nodes.push(first);
+            }
         }
 
-        merge_loopy_loops(&mut inners);
-        if !verify_loopy_loops(&inners) {
-            // If inners are invalid, process outer without inners
-            let empty_inners: Vec<Vec<ProcessedNode>> = vec![];
-            let mut temp_inners = empty_inners;
-            merge_loopy_loops(&mut temp_inners);
-
-            let (min_x, min_z) = editor.get_min_coords();
-            let (max_x, max_z) = editor.get_max_coords();
-            let individual_outers_xz: Vec<Vec<XZPoint>> = individual_outers
-                .iter()
-                .map(|x| x.iter().map(|y| y.xz()).collect::<Vec<_>>())
-                .collect();
-            let empty_inners_xz: Vec<Vec<XZPoint>> = vec![];
-
-            inverse_floodfill(
-                min_x,
-                min_z,
-                max_x,
-                max_z,
-                individual_outers_xz,
-                empty_inners_xz,
-                editor,
-                start_time,
-            );
-            continue;
+        // If no valid outer loops remain, skip the relation
+        if outers.is_empty() {
+            return;
         }
 
-        let (min_x, min_z) = editor.get_min_coords();
-        let (max_x, max_z) = editor.get_max_coords();
-        let individual_outers_xz: Vec<Vec<XZPoint>> = individual_outers
-            .iter()
-            .map(|x| x.iter().map(|y| y.xz()).collect::<Vec<_>>())
-            .collect();
-        let inners_xz: Vec<Vec<XZPoint>> = inners
-            .iter()
-            .map(|x| x.iter().map(|y| y.xz()).collect::<Vec<_>>())
-            .collect();
-
-        inverse_floodfill(
-            min_x,
-            min_z,
-            max_x,
-            max_z,
-            individual_outers_xz,
-            inners_xz,
-            editor,
-            start_time,
-        );
+        // Verify again after filtering and closing
+        if !verify_closed_rings(&outers) {
+            println!("Skipping relation {} due to invalid polygon", element.id);
+            return;
+        }
     }
+
+    merge_way_segments(&mut inners);
+    if !verify_closed_rings(&inners) {
+        println!("Skipping relation {} due to invalid polygon", element.id);
+        return;
+    }
+
+    generate_water_areas(editor, &outers, &inners);
 }
 
-// Merges ways that share nodes into full loops
-fn merge_loopy_loops(loops: &mut Vec<Vec<ProcessedNode>>) {
+fn generate_water_areas(
+    editor: &mut WorldEditor,
+    outers: &[Vec<ProcessedNode>],
+    inners: &[Vec<ProcessedNode>],
+) {
+    // Calculate polygon bounding box to limit fill area
+    let mut poly_min_x = i32::MAX;
+    let mut poly_min_z = i32::MAX;
+    let mut poly_max_x = i32::MIN;
+    let mut poly_max_z = i32::MIN;
+
+    for outer in outers {
+        for node in outer {
+            poly_min_x = poly_min_x.min(node.x);
+            poly_min_z = poly_min_z.min(node.z);
+            poly_max_x = poly_max_x.max(node.x);
+            poly_max_z = poly_max_z.max(node.z);
+        }
+    }
+
+    // If no valid bounds, nothing to fill
+    if poly_min_x == i32::MAX || poly_max_x == i32::MIN {
+        return;
+    }
+
+    // Clamp to world bounds just in case
+    let (world_min_x, world_min_z) = editor.get_min_coords();
+    let (world_max_x, world_max_z) = editor.get_max_coords();
+    let min_x = poly_min_x.max(world_min_x);
+    let min_z = poly_min_z.max(world_min_z);
+    let max_x = poly_max_x.min(world_max_x);
+    let max_z = poly_max_z.min(world_max_z);
+
+    let outers_xz: Vec<Vec<XZPoint>> = outers
+        .iter()
+        .map(|x| x.iter().map(|y| y.xz()).collect::<Vec<_>>())
+        .collect();
+    let inners_xz: Vec<Vec<XZPoint>> = inners
+        .iter()
+        .map(|x| x.iter().map(|y| y.xz()).collect::<Vec<_>>())
+        .collect();
+
+    inverse_floodfill(min_x, min_z, max_x, max_z, outers_xz, inners_xz, editor);
+}
+
+/// Merges way segments that share endpoints into closed rings.
+fn merge_way_segments(rings: &mut Vec<Vec<ProcessedNode>>) {
     let mut removed: Vec<usize> = vec![];
     let mut merged: Vec<Vec<ProcessedNode>> = vec![];
 
-    for i in 0..loops.len() {
-        for j in 0..loops.len() {
+    // Match nodes by ID or proximity (handles synthetic nodes from bbox clipping)
+    let nodes_match = |a: &ProcessedNode, b: &ProcessedNode| -> bool {
+        if a.id == b.id {
+            return true;
+        }
+        let dx = (a.x - b.x).abs();
+        let dz = (a.z - b.z).abs();
+        dx <= 1 && dz <= 1
+    };
+
+    for i in 0..rings.len() {
+        for j in 0..rings.len() {
             if i == j {
                 continue;
             }
@@ -117,20 +191,29 @@ fn merge_loopy_loops(loops: &mut Vec<Vec<ProcessedNode>>) {
                 continue;
             }
 
-            let x: &Vec<ProcessedNode> = &loops[i];
-            let y: &Vec<ProcessedNode> = &loops[j];
+            let x: &Vec<ProcessedNode> = &rings[i];
+            let y: &Vec<ProcessedNode> = &rings[j];
 
-            // it's looped already
-            if x[0].id == x.last().unwrap().id {
+            // Skip empty rings (can happen after clipping)
+            if x.is_empty() || y.is_empty() {
                 continue;
             }
 
-            // it's looped already
-            if y[0].id == y.last().unwrap().id {
+            let x_first = &x[0];
+            let x_last = x.last().unwrap();
+            let y_first = &y[0];
+            let y_last = y.last().unwrap();
+
+            // Skip already-closed rings
+            if nodes_match(x_first, x_last) {
                 continue;
             }
 
-            if x[0].id == y[0].id {
+            if nodes_match(y_first, y_last) {
+                continue;
+            }
+
+            if nodes_match(x_first, y_first) {
                 removed.push(i);
                 removed.push(j);
 
@@ -138,7 +221,7 @@ fn merge_loopy_loops(loops: &mut Vec<Vec<ProcessedNode>>) {
                 x.reverse();
                 x.extend(y.iter().skip(1).cloned());
                 merged.push(x);
-            } else if x.last().unwrap().id == y.last().unwrap().id {
+            } else if nodes_match(x_last, y_last) {
                 removed.push(i);
                 removed.push(j);
 
@@ -146,7 +229,7 @@ fn merge_loopy_loops(loops: &mut Vec<Vec<ProcessedNode>>) {
                 x.extend(y.iter().rev().skip(1).cloned());
 
                 merged.push(x);
-            } else if x[0].id == y.last().unwrap().id {
+            } else if nodes_match(x_first, y_last) {
                 removed.push(i);
                 removed.push(j);
 
@@ -154,7 +237,7 @@ fn merge_loopy_loops(loops: &mut Vec<Vec<ProcessedNode>>) {
                 y.extend(x.iter().skip(1).cloned());
 
                 merged.push(y);
-            } else if x.last().unwrap().id == y[0].id {
+            } else if nodes_match(x_last, y_first) {
                 removed.push(i);
                 removed.push(j);
 
@@ -169,24 +252,35 @@ fn merge_loopy_loops(loops: &mut Vec<Vec<ProcessedNode>>) {
     removed.sort();
 
     for r in removed.iter().rev() {
-        loops.remove(*r);
+        rings.remove(*r);
     }
 
     let merged_len: usize = merged.len();
     for m in merged {
-        loops.push(m);
+        rings.push(m);
     }
 
     if merged_len > 0 {
-        merge_loopy_loops(loops);
+        merge_way_segments(rings);
     }
 }
 
-fn verify_loopy_loops(loops: &[Vec<ProcessedNode>]) -> bool {
-    let mut valid: bool = true;
-    for l in loops {
-        if l[0].id != l.last().unwrap().id {
-            eprintln!("WARN: Disconnected loop");
+/// Verifies all rings are properly closed (first node matches last).
+fn verify_closed_rings(rings: &[Vec<ProcessedNode>]) -> bool {
+    let mut valid = true;
+    for ring in rings {
+        let first = &ring[0];
+        let last = ring.last().unwrap();
+
+        // Check if ring is closed (by ID or proximity)
+        let is_closed = first.id == last.id || {
+            let dx = (first.x - last.x).abs();
+            let dz = (first.z - last.z).abs();
+            dx <= 1 && dz <= 1
+        };
+
+        if !is_closed {
+            eprintln!("WARN: Disconnected ring");
             valid = false;
         }
     }
@@ -206,8 +300,8 @@ fn inverse_floodfill(
     outers: Vec<Vec<XZPoint>>,
     inners: Vec<Vec<XZPoint>>,
     editor: &mut WorldEditor,
-    start_time: Instant,
 ) {
+    // Convert to geo Polygons with normalized winding order
     let inners: Vec<_> = inners
         .into_iter()
         .map(|x| {
@@ -219,6 +313,7 @@ fn inverse_floodfill(
                 ),
                 vec![],
             )
+            .orient(Direction::Default)
         })
         .collect();
 
@@ -233,17 +328,11 @@ fn inverse_floodfill(
                 ),
                 vec![],
             )
+            .orient(Direction::Default)
         })
         .collect();
 
-    inverse_floodfill_recursive(
-        (min_x, min_z),
-        (max_x, max_z),
-        &outers,
-        &inners,
-        editor,
-        start_time,
-    );
+    inverse_floodfill_recursive((min_x, min_z), (max_x, max_z), &outers, &inners, editor);
 }
 
 fn inverse_floodfill_recursive(
@@ -252,12 +341,11 @@ fn inverse_floodfill_recursive(
     outers: &[Polygon],
     inners: &[Polygon],
     editor: &mut WorldEditor,
-    start_time: Instant,
 ) {
-    // Check if we've exceeded 25 seconds
-    if start_time.elapsed().as_secs() > 25 {
-        println!("Water area generation exceeded 25 seconds, continuing anyway");
-    }
+    // Check if we've exceeded 40 seconds
+    // if start_time.elapsed().as_secs() > 40 {
+    //     println!("Water area generation exceeded 40 seconds, continuing anyway");
+    // }
 
     const ITERATIVE_THRES: i64 = 10_000;
 
@@ -312,7 +400,6 @@ fn inverse_floodfill_recursive(
                 &outers_intersects,
                 &inners_intersects,
                 editor,
-                start_time,
             );
         }
     }

src/elevation_data.rs

@@ -1,6 +1,9 @@
 use crate::coordinate_system::{geographic::LLBBox, transformation::geo_distance};
+#[cfg(feature = "gui")]
+use crate::telemetry::{send_log, LogLevel};
 use image::Rgb;
-use std::path::Path;
+use rayon::prelude::*;
+use std::path::{Path, PathBuf};
 
 /// Maximum Y coordinate in Minecraft (build height limit)
 const MAX_Y: i32 = 319;
@@ -15,6 +18,8 @@ const TERRARIUM_OFFSET: f64 = 32768.0;
 const MIN_ZOOM: u8 = 10;
 /// Maximum zoom level for terrain tiles
 const MAX_ZOOM: u8 = 15;
+/// Maximum concurrent tile downloads to be respectful to AWS
+const MAX_CONCURRENT_DOWNLOADS: usize = 8;
 
 /// Holds processed elevation data and metadata
 #[derive(Clone)]
@@ -27,6 +32,11 @@ pub struct ElevationData {
     pub(crate) height: usize,
 }
 
+/// RGB image buffer type for elevation tiles
+type TileImage = image::ImageBuffer<Rgb<u8>, Vec<u8>>;
+/// Result type for tile download operations: ((tile_x, tile_y), image) or error
+type TileDownloadResult = Result<((u32, u32), TileImage), String>;
+
 /// Calculates appropriate zoom level for the given bounding box
 fn calculate_zoom_level(bbox: &LLBBox) -> u8 {
     let lat_diff: f64 = (bbox.max().lat() - bbox.min().lat()).abs();
@@ -44,6 +54,110 @@ fn lat_lng_to_tile(lat: f64, lng: f64, zoom: u8) -> (u32, u32) {
     (x, y)
 }
 
+/// Downloads a tile from AWS Terrain Tiles service
+fn download_tile(
+    client: &reqwest::blocking::Client,
+    tile_x: u32,
+    tile_y: u32,
+    zoom: u8,
+    tile_path: &Path,
+) -> Result<image::ImageBuffer<Rgb<u8>, Vec<u8>>, String> {
+    println!("Fetching tile x={tile_x},y={tile_y},z={zoom} from AWS Terrain Tiles");
+    let url: String = AWS_TERRARIUM_URL
+        .replace("{z}", &zoom.to_string())
+        .replace("{x}", &tile_x.to_string())
+        .replace("{y}", &tile_y.to_string());
+
+    let response = client.get(&url).send().map_err(|e| e.to_string())?;
+    response.error_for_status_ref().map_err(|e| e.to_string())?;
+    let bytes = response.bytes().map_err(|e| e.to_string())?;
+    std::fs::write(tile_path, &bytes).map_err(|e| e.to_string())?;
+    let img = image::load_from_memory(&bytes).map_err(|e| e.to_string())?;
+    Ok(img.to_rgb8())
+}
+
+/// Fetches a tile from cache or downloads it if not available
+/// Note: In parallel execution, multiple threads may attempt to download the same tile
+/// if it's missing or corrupted. This is harmless (just wastes some bandwidth) as
+/// file writes are atomic at the OS level.
+fn fetch_or_load_tile(
+    client: &reqwest::blocking::Client,
+    tile_x: u32,
+    tile_y: u32,
+    zoom: u8,
+    tile_path: &Path,
+) -> Result<image::ImageBuffer<Rgb<u8>, Vec<u8>>, String> {
+    if tile_path.exists() {
+        // Check if the cached file has a reasonable size (PNG files should be at least a few KB)
+        let file_size = std::fs::metadata(tile_path).map(|m| m.len()).unwrap_or(0);
+
+        if file_size < 1000 {
+            eprintln!(
+                "Warning: Cached tile at {} appears to be too small ({} bytes). Refetching tile.",
+                tile_path.display(),
+                file_size
+            );
+            #[cfg(feature = "gui")]
+            send_log(
+                LogLevel::Warning,
+                "Cached tile appears too small, refetching.",
+            );
+
+            // Remove the potentially corrupted file
+            if let Err(e) = std::fs::remove_file(tile_path) {
+                eprintln!("Warning: Failed to remove corrupted tile file: {e}");
+                #[cfg(feature = "gui")]
+                send_log(
+                    LogLevel::Warning,
+                    "Failed to remove corrupted tile file during refetching.",
+                );
+            }
+
+            // Re-download the tile
+            return download_tile(client, tile_x, tile_y, zoom, tile_path);
+        }
+
+        // Try to load cached tile, but handle corruption gracefully
+        match image::open(tile_path) {
+            Ok(img) => {
+                println!(
+                    "Loading cached tile x={tile_x},y={tile_y},z={zoom} from {}",
+                    tile_path.display()
+                );
+                Ok(img.to_rgb8())
+            }
+            Err(e) => {
+                eprintln!(
+                    "Cached tile at {} is corrupted or invalid: {}. Re-downloading...",
+                    tile_path.display(),
+                    e
+                );
+                #[cfg(feature = "gui")]
+                send_log(
+                    LogLevel::Warning,
+                    "Cached tile is corrupted or invalid. Re-downloading...",
+                );
+
+                // Remove the corrupted file
+                if let Err(e) = std::fs::remove_file(tile_path) {
+                    eprintln!("Warning: Failed to remove corrupted tile file: {e}");
+                    #[cfg(feature = "gui")]
+                    send_log(
+                        LogLevel::Warning,
+                        "Failed to remove corrupted tile file during re-download.",
+                    );
+                }
+
+                // Re-download the tile
+                download_tile(client, tile_x, tile_y, zoom, tile_path)
+            }
+        }
+    } else {
+        // Download the tile for the first time
+        download_tile(client, tile_x, tile_y, zoom, tile_path)
+    }
+}
+
 pub fn fetch_elevation_data(
     bbox: &LLBBox,
     scale: f64,
@@ -67,51 +181,68 @@ pub fn fetch_elevation_data(
     let mut height_grid: Vec<Vec<f64>> = vec![vec![f64::NAN; grid_width]; grid_height];
     let mut extreme_values_found = Vec::new(); // Track extreme values for debugging
 
-    let client: reqwest::blocking::Client = reqwest::blocking::Client::new();
-
-    let tile_cache_dir = Path::new("./arnis-tile-cache");
+    let tile_cache_dir = PathBuf::from("./arnis-tile-cache");
     if !tile_cache_dir.exists() {
-        std::fs::create_dir_all(tile_cache_dir)?;
+        std::fs::create_dir_all(&tile_cache_dir)?;
     }
 
-    // Fetch and process each tile
-    for (tile_x, tile_y) in &tiles {
-        // Check if tile is already cached
-        let tile_path = tile_cache_dir.join(format!("z{zoom}_x{tile_x}_y{tile_y}.png"));
+    // Create a shared HTTP client for connection pooling
+    let client = reqwest::blocking::Client::new();
 
-        let rgb_img: image::ImageBuffer<Rgb<u8>, Vec<u8>> = if tile_path.exists() {
-            println!(
-                "Loading cached tile x={tile_x},y={tile_y},z={zoom} from {}",
-                tile_path.display()
-            );
-            let img: image::DynamicImage = image::open(&tile_path)?;
-            img.to_rgb8()
-        } else {
-            // AWS Terrain Tiles don't require an API key
-            println!("Fetching tile x={tile_x},y={tile_y},z={zoom} from AWS Terrain Tiles");
-            let url: String = AWS_TERRARIUM_URL
-                .replace("{z}", &zoom.to_string())
-                .replace("{x}", &tile_x.to_string())
-                .replace("{y}", &tile_y.to_string());
+    // Download tiles in parallel with limited concurrency to be respectful to AWS
+    let num_tiles = tiles.len();
+    println!(
+        "Downloading {num_tiles} elevation tiles (up to {MAX_CONCURRENT_DOWNLOADS} concurrent)..."
+    );
 
-            let response: reqwest::blocking::Response = client.get(&url).send()?;
-            response.error_for_status_ref()?;
-            let bytes = response.bytes()?;
-            std::fs::write(&tile_path, &bytes)?;
-            let img: image::DynamicImage = image::load_from_memory(&bytes)?;
-            img.to_rgb8()
-        };
+    // Use a custom thread pool to limit concurrent downloads
+    let thread_pool = rayon::ThreadPoolBuilder::new()
+        .num_threads(MAX_CONCURRENT_DOWNLOADS)
+        .build()
+        .map_err(|e| format!("Failed to create thread pool: {e}"))?;
 
+    let downloaded_tiles: Vec<TileDownloadResult> = thread_pool.install(|| {
+        tiles
+            .par_iter()
+            .map(|(tile_x, tile_y)| {
+                let tile_path = tile_cache_dir.join(format!("z{zoom}_x{tile_x}_y{tile_y}.png"));
+
+                let rgb_img = fetch_or_load_tile(&client, *tile_x, *tile_y, zoom, &tile_path)?;
+                Ok(((*tile_x, *tile_y), rgb_img))
+            })
+            .collect()
+    });
+
+    // Check for any download errors
+    let mut successful_tiles = Vec::new();
+    for result in downloaded_tiles {
+        match result {
+            Ok(tile_data) => successful_tiles.push(tile_data),
+            Err(e) => {
+                eprintln!("Warning: Failed to download tile: {e}");
+                #[cfg(feature = "gui")]
+                send_log(
+                    LogLevel::Warning,
+                    &format!("Failed to download elevation tile: {e}"),
+                );
+            }
+        }
+    }
+
+    println!("Processing {} elevation tiles...", successful_tiles.len());
+
+    // Process tiles sequentially (writes to shared height_grid)
+    for ((tile_x, tile_y), rgb_img) in successful_tiles {
         // Only process pixels that fall within the requested bbox
         for (y, row) in rgb_img.rows().enumerate() {
             for (x, pixel) in row.enumerate() {
                 // Convert tile pixel coordinates back to geographic coordinates
-                let pixel_lng = ((*tile_x as f64 + x as f64 / 256.0) / (2.0_f64.powi(zoom as i32)))
+                let pixel_lng = ((tile_x as f64 + x as f64 / 256.0) / (2.0_f64.powi(zoom as i32)))
                     * 360.0
                     - 180.0;
                 let pixel_lat_rad = std::f64::consts::PI
                     * (1.0
-                        - 2.0 * (*tile_y as f64 + y as f64 / 256.0) / (2.0_f64.powi(zoom as i32)));
+                        - 2.0 * (tile_y as f64 + y as f64 / 256.0) / (2.0_f64.powi(zoom as i32)));
                 let pixel_lat = pixel_lat_rad.sinh().atan().to_degrees();
 
                 // Skip pixels outside the requested bounding box
@@ -172,25 +303,26 @@ pub fn fetch_elevation_data(
     filter_elevation_outliers(&mut height_grid);
 
     // Calculate blur sigma based on grid resolution
-    // Reference points for tuning:
-    const SMALL_GRID_REF: f64 = 100.0; // Reference grid size
-    const SMALL_SIGMA_REF: f64 = 15.0; // Sigma for 100x100 grid
-    const LARGE_GRID_REF: f64 = 1000.0; // Reference grid size
-    const LARGE_SIGMA_REF: f64 = 7.0; // Sigma for 1000x1000 grid
+    // Use sqrt scaling to maintain consistent relative smoothing across different area sizes.
+    // This prevents larger generation areas from appearing noisier than smaller ones.
+    // Reference: 100x100 grid uses sigma=5 (5% relative blur)
+    const BASE_GRID_REF: f64 = 100.0;
+    const BASE_SIGMA_REF: f64 = 5.0;
 
     let grid_size: f64 = (grid_width.min(grid_height) as f64).max(1.0);
 
-    let sigma: f64 = if grid_size <= SMALL_GRID_REF {
-        // Linear scaling for small grids
-        SMALL_SIGMA_REF * (grid_size / SMALL_GRID_REF)
-    } else {
-        // Logarithmic scaling for larger grids
-        let ln_small: f64 = SMALL_GRID_REF.ln();
-        let ln_large: f64 = LARGE_GRID_REF.ln();
-        let log_grid_size: f64 = grid_size.ln();
-        let t: f64 = (log_grid_size - ln_small) / (ln_large - ln_small);
-        SMALL_SIGMA_REF + t * (LARGE_SIGMA_REF - SMALL_SIGMA_REF)
-    };
+    // Sqrt scaling provides a good balance:
+    // - 100x100: sigma = 5 (5% relative)
+    // - 500x500: sigma ≈ 11.2 (2.2% relative)
+    // - 1000x1000: sigma ≈ 15.8 (1.6% relative)
+    // This smooths terrain proportionally while preserving more detail.
+    let sigma: f64 = BASE_SIGMA_REF * (grid_size / BASE_GRID_REF).sqrt();
+
+    let blur_percentage: f64 = (sigma / grid_size) * 100.0;
+    eprintln!(
+        "Elevation blur: grid={}x{}, sigma={:.2}, blur_percentage={:.2}%",
+        grid_width, grid_height, sigma, blur_percentage
+    );
 
     /* eprintln!(
         "Grid: {}x{}, Blur sigma: {:.2}",
@@ -200,6 +332,9 @@ pub fn fetch_elevation_data(
     // Continue with the existing blur and conversion to Minecraft heights...
     let blurred_heights: Vec<Vec<f64>> = apply_gaussian_blur(&height_grid, sigma);
 
+    // Release raw height grid
+    drop(height_grid);
+
     let mut mc_heights: Vec<Vec<i32>> = Vec::with_capacity(blurred_heights.len());
 
     // Find min/max in raw data

src/floodfill.rs

@@ -71,7 +71,7 @@ fn optimized_flood_fill_area(
 
     for z in (min_z..=max_z).step_by(step_z as usize) {
         for x in (min_x..=max_x).step_by(step_x as usize) {
-            // Fast timeout check - only every few iterations
+            // Fast timeout check, only every few iterations
             if filled_area.len() % 100 == 0 {
                 if let Some(timeout) = timeout {
                     if start_time.elapsed() > *timeout {
@@ -160,11 +160,10 @@ fn original_flood_fill_area(
     for z in (min_z..=max_z).step_by(step_z as usize) {
         for x in (min_x..=max_x).step_by(step_x as usize) {
             // Reduced timeout checking frequency for better performance
-            if global_visited.len() % 200 == 0 {
-                if let Some(timeout) = timeout {
-                    if &start_time.elapsed() > timeout {
-                        return filled_area;
-                    }
+            // Use manual % check since is_multiple_of() is unstable on stable Rust
+            if let Some(timeout) = timeout {
+                if &start_time.elapsed() > timeout {
+                    return filled_area;
                 }
             }
 

src/floodfill_cache.rs

@@ -0,0 +1,189 @@
+//! Pre-computed flood fill cache for parallel polygon filling.
+//!
+//! This module provides a way to pre-compute all flood fill operations in parallel
+//! before the main element processing loop, then retrieve cached results during
+//! sequential processing.
+
+use crate::floodfill::flood_fill_area;
+use crate::osm_parser::{ProcessedElement, ProcessedWay};
+use fnv::FnvHashMap;
+use rayon::prelude::*;
+use std::time::Duration;
+
+/// A cache of pre-computed flood fill results, keyed by element ID.
+pub struct FloodFillCache {
+    /// Cached results: element_id -> filled coordinates
+    way_cache: FnvHashMap<u64, Vec<(i32, i32)>>,
+}
+
+impl FloodFillCache {
+    /// Creates an empty cache.
+    pub fn new() -> Self {
+        Self {
+            way_cache: FnvHashMap::default(),
+        }
+    }
+
+    /// Pre-computes flood fills for all elements that need them.
+    ///
+    /// This runs in parallel using Rayon, taking advantage of multiple CPU cores.
+    pub fn precompute(elements: &[ProcessedElement], timeout: Option<&Duration>) -> Self {
+        // Collect all ways that need flood fill
+        let ways_needing_fill: Vec<&ProcessedWay> = elements
+            .iter()
+            .filter_map(|el| match el {
+                ProcessedElement::Way(way) => {
+                    if Self::way_needs_flood_fill(way) {
+                        Some(way)
+                    } else {
+                        None
+                    }
+                }
+                _ => None,
+            })
+            .collect();
+
+        // Compute all way flood fills in parallel
+        let way_results: Vec<(u64, Vec<(i32, i32)>)> = ways_needing_fill
+            .par_iter()
+            .map(|way| {
+                let polygon_coords: Vec<(i32, i32)> =
+                    way.nodes.iter().map(|n| (n.x, n.z)).collect();
+                let filled = flood_fill_area(&polygon_coords, timeout);
+                (way.id, filled)
+            })
+            .collect();
+
+        // Build the cache
+        let mut cache = Self::new();
+        for (id, filled) in way_results {
+            cache.way_cache.insert(id, filled);
+        }
+
+        cache
+    }
+
+    /// Gets cached flood fill result for a way, or computes it if not cached.
+    ///
+    /// Note: Combined ways created from relations (e.g., in `generate_natural_from_relation`)
+    /// will miss the cache and fall back to on-demand computation. This is by design,
+    /// these synthetic ways don't exist in the original element list and have relation IDs
+    /// rather than way IDs. The individual member ways are still cached.
+    pub fn get_or_compute(
+        &self,
+        way: &ProcessedWay,
+        timeout: Option<&Duration>,
+    ) -> Vec<(i32, i32)> {
+        if let Some(cached) = self.way_cache.get(&way.id) {
+            // Clone is intentional: each result is typically accessed once during
+            // sequential processing, so the cost is acceptable vs Arc complexity
+            cached.clone()
+        } else {
+            // Fallback: compute on demand for synthetic/combined ways from relations
+            let polygon_coords: Vec<(i32, i32)> = way.nodes.iter().map(|n| (n.x, n.z)).collect();
+            flood_fill_area(&polygon_coords, timeout)
+        }
+    }
+
+    /// Gets cached flood fill result for a ProcessedElement (Way only).
+    /// For Nodes/Relations, returns empty vec.
+    pub fn get_or_compute_element(
+        &self,
+        element: &ProcessedElement,
+        timeout: Option<&Duration>,
+    ) -> Vec<(i32, i32)> {
+        match element {
+            ProcessedElement::Way(way) => self.get_or_compute(way, timeout),
+            _ => Vec::new(),
+        }
+    }
+
+    /// Determines if a way element needs flood fill based on its tags.
+    ///
+    /// This checks for tag presence (not specific values) because:
+    /// - Only some values within each tag type actually use flood fill
+    /// - But caching extra results is harmless (small memory overhead)
+    /// - And avoids duplicating value-checking logic from processors
+    ///
+    /// Covered cases:
+    /// - building/building:part -> buildings::generate_buildings (includes bridge)
+    /// - landuse -> landuse::generate_landuse
+    /// - leisure -> leisure::generate_leisure
+    /// - amenity -> amenities::generate_amenities
+    /// - natural (except tree) -> natural::generate_natural
+    /// - highway with area=yes -> highways::generate_highways (area fill)
+    fn way_needs_flood_fill(way: &ProcessedWay) -> bool {
+        way.tags.contains_key("building")
+            || way.tags.contains_key("building:part")
+            || way.tags.contains_key("landuse")
+            || way.tags.contains_key("leisure")
+            || way.tags.contains_key("amenity")
+            || way
+                .tags
+                .get("natural")
+                .map(|v| v != "tree")
+                .unwrap_or(false)
+            // Highway areas (like pedestrian plazas) use flood fill when area=yes
+            || (way.tags.contains_key("highway")
+                && way.tags.get("area").map(|v| v == "yes").unwrap_or(false))
+    }
+
+    /// Returns the number of cached way entries.
+    pub fn way_count(&self) -> usize {
+        self.way_cache.len()
+    }
+
+    /// Removes a way's cached flood fill result, freeing memory.
+    ///
+    /// Call this after processing an element to release its cached data.
+    pub fn remove_way(&mut self, way_id: u64) {
+        self.way_cache.remove(&way_id);
+    }
+
+    /// Removes all cached flood fill results for ways in a relation.
+    ///
+    /// Relations contain multiple ways, so we need to remove all of them.
+    pub fn remove_relation_ways(&mut self, way_ids: &[u64]) {
+        for &id in way_ids {
+            self.way_cache.remove(&id);
+        }
+    }
+}
+
+impl Default for FloodFillCache {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Configures the global Rayon thread pool with a CPU usage cap.
+///
+/// Call this once at startup before any parallel operations.
+///
+/// # Arguments
+/// * `cpu_fraction` - Fraction of available cores to use (e.g., 0.9 for 90%).
+///   Values are clamped to the range [0.1, 1.0].
+pub fn configure_rayon_thread_pool(cpu_fraction: f64) {
+    // Clamp cpu_fraction to valid range
+    let cpu_fraction = cpu_fraction.clamp(0.1, 1.0);
+
+    let available_cores = std::thread::available_parallelism()
+        .map(|n| n.get())
+        .unwrap_or(4);
+
+    let target_threads = ((available_cores as f64) * cpu_fraction).floor() as usize;
+    let target_threads = target_threads.max(1); // At least 1 thread
+
+    // Only configure if we haven't already (this can only be called once)
+    match rayon::ThreadPoolBuilder::new()
+        .num_threads(target_threads)
+        .build_global()
+    {
+        Ok(()) => {
+            // Successfully configured (silent to avoid cluttering output)
+        }
+        Err(_) => {
+            // Thread pool already configured
+        }
+    }
+}

src/ground.rs

@@ -23,12 +23,22 @@ impl Ground {
     }
 
     pub fn new_enabled(bbox: &LLBBox, scale: f64, ground_level: i32) -> Self {
-        let elevation_data = fetch_elevation_data(bbox, scale, ground_level)
-            .expect("Failed to fetch elevation data");
-        Self {
-            elevation_enabled: true,
-            ground_level,
-            elevation_data: Some(elevation_data),
+        match fetch_elevation_data(bbox, scale, ground_level) {
+            Ok(elevation_data) => Self {
+                elevation_enabled: true,
+                ground_level,
+                elevation_data: Some(elevation_data),
+            },
+            Err(e) => {
+                eprintln!("Failed to fetch elevation data: {}", e);
+                emit_gui_progress_update(15.0, "Elevation unavailable, using flat ground");
+                // Graceful fallback: disable elevation and keep provided ground_level
+                Self {
+                    elevation_enabled: false,
+                    ground_level,
+                    elevation_data: None,
+                }
+            }
         }
     }
 

src/gui.rs

@@ -1,21 +1,25 @@
 use crate::args::Args;
 use crate::coordinate_system::cartesian::XZPoint;
 use crate::coordinate_system::geographic::{LLBBox, LLPoint};
-use crate::data_processing;
+use crate::coordinate_system::transformation::CoordTransformer;
+use crate::data_processing::{self, GenerationOptions};
 use crate::ground::{self, Ground};
 use crate::map_transformation;
 use crate::osm_parser;
-use crate::progress;
+use crate::progress::{self, emit_gui_progress_update};
 use crate::retrieve_data;
+use crate::telemetry::{self, send_log, LogLevel};
 use crate::version_check;
+use crate::world_editor::WorldFormat;
+use colored::Colorize;
 use fastnbt::Value;
 use flate2::read::GzDecoder;
 use fs2::FileExt;
-use log::{error, LevelFilter};
+use log::LevelFilter;
 use rfd::FileDialog;
 use std::io::Read;
 use std::path::{Path, PathBuf};
-use std::{env, fs, io::Write, panic};
+use std::{env, fs, io::Write};
 use tauri_plugin_log::{Builder as LogBuilder, Target, TargetKind};
 
 /// Manages the session.lock file for a Minecraft world directory
@@ -58,16 +62,26 @@ impl Drop for SessionLock {
     }
 }
 
+/// Gets the area name for a given bounding box using the center point
+fn get_area_name_for_bedrock(bbox: &LLBBox) -> String {
+    let center_lat = (bbox.min().lat() + bbox.max().lat()) / 2.0;
+    let center_lon = (bbox.min().lng() + bbox.max().lng()) / 2.0;
+
+    match retrieve_data::fetch_area_name(center_lat, center_lon) {
+        Ok(Some(name)) => name,
+        _ => "Unknown Location".to_string(),
+    }
+}
+
 pub fn run_gui() {
+    // Configure thread pool with 90% CPU cap to keep system responsive
+    crate::floodfill_cache::configure_rayon_thread_pool(0.9);
+
     // Launch the UI
     println!("Launching UI...");
 
-    // Set a custom panic hook to log panic information
-    panic::set_hook(Box::new(|panic_info| {
-        let message = format!("Application panicked: {panic_info:?}");
-        error!("{message}");
-        std::process::exit(1);
-    }));
+    // Install panic hook for crash reporting
+    telemetry::install_panic_hook();
 
     // Workaround WebKit2GTK issue with NVIDIA drivers and graphics issues
     // Source: https://github.com/tauri-apps/tauri/issues/10702
@@ -102,7 +116,9 @@ pub fn run_gui() {
             gui_select_world,
             gui_start_generation,
             gui_get_version,
-            gui_check_for_updates
+            gui_check_for_updates,
+            gui_get_world_map_data,
+            gui_show_in_folder
         ])
         .setup(|app| {
             let app_handle = app.handle();
@@ -226,13 +242,13 @@ fn create_new_world(base_path: &Path) -> Result<String, String> {
         .map_err(|e| format!("Failed to create world directory: {e}"))?;
 
     // Copy the region template file
-    const REGION_TEMPLATE: &[u8] = include_bytes!("../mcassets/region.template");
+    const REGION_TEMPLATE: &[u8] = include_bytes!("../assets/minecraft/region.template");
     let region_path = new_world_path.join("region").join("r.0.0.mca");
     fs::write(&region_path, REGION_TEMPLATE)
         .map_err(|e| format!("Failed to create region file: {e}"))?;
 
     // Add the level.dat file
-    const LEVEL_TEMPLATE: &[u8] = include_bytes!("../mcassets/level.dat");
+    const LEVEL_TEMPLATE: &[u8] = include_bytes!("../assets/minecraft/level.dat");
 
     // Decompress the gzipped level.template
     let mut decoder = GzDecoder::new(LEVEL_TEMPLATE);
@@ -299,7 +315,7 @@ fn create_new_world(base_path: &Path) -> Result<String, String> {
         .map_err(|e| format!("Failed to create level.dat file: {e}"))?;
 
     // Add the icon.png file
-    const ICON_TEMPLATE: &[u8] = include_bytes!("../mcassets/icon.png");
+    const ICON_TEMPLATE: &[u8] = include_bytes!("../assets/minecraft/icon.png");
     fs::write(new_world_path.join("icon.png"), ICON_TEMPLATE)
         .map_err(|e| format!("Failed to create icon.png file: {e}"))?;
 
@@ -307,52 +323,45 @@ fn create_new_world(base_path: &Path) -> Result<String, String> {
 }
 
 /// Adds localized area name to the world name in level.dat
-fn add_localized_world_name(world_path_str: &str, bbox: &LLBBox) -> String {
-    let world_path = PathBuf::from(world_path_str);
-
+fn add_localized_world_name(world_path: PathBuf, bbox: &LLBBox) -> PathBuf {
     // Only proceed if the path exists
     if !world_path.exists() {
-        return world_path_str.to_string();
+        return world_path;
     }
 
     // Check the level.dat file first to get the current name
     let level_path = world_path.join("level.dat");
 
     if !level_path.exists() {
-        return world_path_str.to_string();
+        return world_path;
     }
 
     // Try to read the current world name from level.dat
-    let current_name = match std::fs::read(&level_path) {
-        Ok(level_data) => {
-            let mut decoder = GzDecoder::new(level_data.as_slice());
-            let mut decompressed_data = Vec::new();
-            if decoder.read_to_end(&mut decompressed_data).is_ok() {
-                if let Ok(Value::Compound(ref root)) =
-                    fastnbt::from_bytes::<Value>(&decompressed_data)
-                {
-                    if let Some(Value::Compound(ref data)) = root.get("Data") {
-                        if let Some(Value::String(name)) = data.get("LevelName") {
-                            name.clone()
-                        } else {
-                            return world_path_str.to_string();
-                        }
-                    } else {
-                        return world_path_str.to_string();
-                    }
-                } else {
-                    return world_path_str.to_string();
-                }
-            } else {
-                return world_path_str.to_string();
-            }
-        }
-        Err(_) => return world_path_str.to_string(),
+    let Ok(level_data) = std::fs::read(&level_path) else {
+        return world_path;
+    };
+
+    let mut decoder = GzDecoder::new(level_data.as_slice());
+    let mut decompressed_data = Vec::new();
+    if decoder.read_to_end(&mut decompressed_data).is_err() {
+        return world_path;
+    }
+
+    let Ok(Value::Compound(ref root)) = fastnbt::from_bytes::<Value>(&decompressed_data) else {
+        return world_path;
+    };
+
+    let Some(Value::Compound(ref data)) = root.get("Data") else {
+        return world_path;
+    };
+
+    let Some(Value::String(current_name)) = data.get("LevelName") else {
+        return world_path;
     };
 
     // Only modify if it's an Arnis world and doesn't already have an area name
     if !current_name.starts_with("Arnis World ") || current_name.contains(": ") {
-        return world_path_str.to_string();
+        return world_path;
     }
 
     // Calculate center coordinates of bbox
@@ -362,7 +371,7 @@ fn add_localized_world_name(world_path_str: &str, bbox: &LLBBox) -> String {
     // Try to fetch the area name
     let area_name = match retrieve_data::fetch_area_name(center_lat, center_lon) {
         Ok(Some(name)) => name,
-        _ => return world_path_str.to_string(), // Keep original name if no area name found
+        _ => return world_path, // Keep original name if no area name found
     };
 
     // Create new name with localized area name, ensuring total length doesn't exceed 30 characters
@@ -378,7 +387,7 @@ fn add_localized_world_name(world_path_str: &str, bbox: &LLBBox) -> String {
                 .collect::<String>()
         } else if max_area_name_len == 0 {
             // If base name is already too long, don't add area name
-            return world_path_str.to_string();
+            return world_path;
         } else {
             area_name
         };
@@ -406,6 +415,10 @@ fn add_localized_world_name(world_path_str: &str, bbox: &LLBBox) -> String {
                                 if let Ok(compressed_data) = encoder.finish() {
                                     if let Err(e) = std::fs::write(&level_path, compressed_data) {
                                         eprintln!("Failed to update level.dat with area name: {e}");
+                                        send_log(
+                                            LogLevel::Warning,
+                                            "Failed to update level.dat with area name",
+                                        );
                                     }
                                 }
                             }
@@ -417,7 +430,7 @@ fn add_localized_world_name(world_path_str: &str, bbox: &LLBBox) -> String {
     }
 
     // Return the original path since we didn't change the directory name
-    world_path_str.to_string()
+    world_path
 }
 
 // Function to update player position in level.dat based on spawn point coordinates
@@ -528,7 +541,7 @@ fn update_player_position(
 
 // Function to update player spawn Y coordinate based on terrain height after generation
 pub fn update_player_spawn_y_after_generation(
-    world_path: &str,
+    world_path: &Path,
     spawn_point: Option<(f64, f64)>,
     bbox_text: String,
     scale: f64,
@@ -668,6 +681,114 @@ fn gui_check_for_updates() -> Result<bool, String> {
     }
 }
 
+/// Returns the world map image data as base64 and geo bounds for overlay display.
+/// Returns None if the map image or metadata doesn't exist.
+#[tauri::command]
+fn gui_get_world_map_data(world_path: String) -> Result<Option<WorldMapData>, String> {
+    let world_dir = PathBuf::from(&world_path);
+    let map_path = world_dir.join("arnis_world_map.png");
+    let metadata_path = world_dir.join("metadata.json");
+
+    // Check if both files exist
+    if !map_path.exists() || !metadata_path.exists() {
+        return Ok(None);
+    }
+
+    // Read and encode the map image as base64
+    let image_data = fs::read(&map_path).map_err(|e| format!("Failed to read map image: {e}"))?;
+    let base64_image =
+        base64::Engine::encode(&base64::engine::general_purpose::STANDARD, &image_data);
+
+    // Read metadata
+    let metadata_content =
+        fs::read_to_string(&metadata_path).map_err(|e| format!("Failed to read metadata: {e}"))?;
+    let metadata: serde_json::Value = serde_json::from_str(&metadata_content)
+        .map_err(|e| format!("Failed to parse metadata: {e}"))?;
+
+    // Extract geo bounds (metadata uses camelCase from serde)
+    let min_lat = metadata["minGeoLat"]
+        .as_f64()
+        .ok_or("Missing minGeoLat in metadata")?;
+    let max_lat = metadata["maxGeoLat"]
+        .as_f64()
+        .ok_or("Missing maxGeoLat in metadata")?;
+    let min_lon = metadata["minGeoLon"]
+        .as_f64()
+        .ok_or("Missing minGeoLon in metadata")?;
+    let max_lon = metadata["maxGeoLon"]
+        .as_f64()
+        .ok_or("Missing maxGeoLon in metadata")?;
+
+    Ok(Some(WorldMapData {
+        image_base64: format!("data:image/png;base64,{}", base64_image),
+        min_lat,
+        max_lat,
+        min_lon,
+        max_lon,
+    }))
+}
+
+/// Data structure for world map overlay
+#[derive(serde::Serialize)]
+struct WorldMapData {
+    image_base64: String,
+    min_lat: f64,
+    max_lat: f64,
+    min_lon: f64,
+    max_lon: f64,
+}
+
+/// Opens the file with default application (Windows) or shows in file explorer (macOS/Linux)
+#[tauri::command]
+fn gui_show_in_folder(path: String) -> Result<(), String> {
+    #[cfg(target_os = "windows")]
+    {
+        // On Windows, try to open with default application (Minecraft Bedrock)
+        // If that fails, show in Explorer
+        if std::process::Command::new("cmd")
+            .args(["/C", "start", "", &path])
+            .spawn()
+            .is_err()
+        {
+            std::process::Command::new("explorer")
+                .args(["/select,", &path])
+                .spawn()
+                .map_err(|e| format!("Failed to open explorer: {}", e))?;
+        }
+    }
+
+    #[cfg(target_os = "macos")]
+    {
+        // On macOS, just reveal in Finder
+        std::process::Command::new("open")
+            .args(["-R", &path])
+            .spawn()
+            .map_err(|e| format!("Failed to open Finder: {}", e))?;
+    }
+
+    #[cfg(target_os = "linux")]
+    {
+        // On Linux, just show in file manager
+        let path_parent = std::path::Path::new(&path)
+            .parent()
+            .map(|p| p.to_string_lossy().to_string())
+            .unwrap_or_else(|| path.clone());
+
+        // Try nautilus with select first, then fall back to xdg-open on parent
+        if std::process::Command::new("nautilus")
+            .args(["--select", &path])
+            .spawn()
+            .is_err()
+        {
+            let _ = std::process::Command::new("xdg-open")
+                .arg(&path_parent)
+                .spawn();
+        }
+    }
+
+    Ok(())
+}
+
 #[tauri::command]
 #[allow(clippy::too_many_arguments)]
 #[allow(unused_variables)]
@@ -676,19 +797,29 @@ fn gui_start_generation(
     selected_world: String,
     world_scale: f64,
     ground_level: i32,
-    floodfill_timeout: u64,
     terrain_enabled: bool,
+    skip_osm_objects: bool,
     interior_enabled: bool,
     roof_enabled: bool,
     fillground_enabled: bool,
     is_new_world: bool,
     spawn_point: Option<(f64, f64)>,
+    telemetry_consent: bool,
+    world_format: String,
 ) -> Result<(), String> {
     use progress::emit_gui_error;
     use LLBBox;
 
+    // Store telemetry consent for crash reporting
+    telemetry::set_telemetry_consent(telemetry_consent);
+
+    // Send generation click telemetry
+    telemetry::send_generation_click();
+
     // If spawn point was chosen and the world is new, check and set the spawn point
-    if is_new_world && spawn_point.is_some() {
+    // Only update player position for Java worlds - Bedrock worlds don't have a pre-existing
+    // level.dat to modify (the spawn point will be set when the .mcworld is created)
+    if is_new_world && spawn_point.is_some() && world_format != "bedrock" {
         // Verify the spawn point is within bounds
         if let Some(coords) = spawn_point {
             let llbbox = match LLBBox::from_str(&bbox_text) {
@@ -719,16 +850,52 @@ fn gui_start_generation(
 
     tauri::async_runtime::spawn(async move {
         if let Err(e) = tokio::task::spawn_blocking(move || {
-            // Acquire session lock for the world directory before starting generation
             let world_path = PathBuf::from(&selected_world);
-            let _session_lock = match SessionLock::acquire(&world_path) {
-                Ok(lock) => lock,
-                Err(e) => {
-                    let error_msg = format!("Failed to acquire session lock: {e}");
+
+            // Determine world format from UI selection first (needed for session lock decision)
+            let world_format = if world_format == "bedrock" {
+                WorldFormat::BedrockMcWorld
+            } else {
+                WorldFormat::JavaAnvil
+            };
+
+            // Check available disk space before starting generation (minimum 3GB required)
+            const MIN_DISK_SPACE_BYTES: u64 = 3 * 1024 * 1024 * 1024; // 3 GB
+            let check_path = if world_format == WorldFormat::JavaAnvil {
+                world_path.clone()
+            } else {
+                // For Bedrock, check current directory where .mcworld will be created
+                std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."))
+            };
+            match fs2::available_space(&check_path) {
+                Ok(available) if available < MIN_DISK_SPACE_BYTES => {
+                    let error_msg = "Not enough disk space available.".to_string();
                     eprintln!("{error_msg}");
                     emit_gui_error(&error_msg);
                     return Err(error_msg);
                 }
+                Err(e) => {
+                    // Log warning but don't block generation if we can't check space
+                    eprintln!("Warning: Could not check disk space: {e}");
+                }
+                _ => {} // Sufficient space available
+            }
+
+            // Acquire session lock for Java worlds only
+            // Session lock prevents Minecraft from having the world open during generation
+            // Bedrock worlds are generated as .mcworld files and don't need this lock
+            let _session_lock: Option<SessionLock> = if world_format == WorldFormat::JavaAnvil {
+                match SessionLock::acquire(&world_path) {
+                    Ok(lock) => Some(lock),
+                    Err(e) => {
+                        let error_msg = format!("Failed to acquire session lock: {e}");
+                        eprintln!("{error_msg}");
+                        emit_gui_error(&error_msg);
+                        return Err(error_msg);
+                    }
+                }
+            } else {
+                None
             };
 
             // Parse the bounding box from the text with proper error handling
@@ -742,19 +909,66 @@ fn gui_start_generation(
                 }
             };
 
-            // Add localized name to the world if user generated a new world
-            let updated_world_path = if is_new_world {
-                add_localized_world_name(&selected_world, &bbox)
-            } else {
-                selected_world.clone()
+            // Determine output path and level name based on format
+            let (generation_path, level_name) = match world_format {
+                WorldFormat::JavaAnvil => {
+                    // Java: use the selected world path, add localized name if new
+                    let updated_path = if is_new_world {
+                        add_localized_world_name(world_path.clone(), &bbox)
+                    } else {
+                        world_path.clone()
+                    };
+                    (updated_path, None)
+                }
+                WorldFormat::BedrockMcWorld => {
+                    // Bedrock: generate .mcworld in current directory with location-based name
+                    let area_name = get_area_name_for_bedrock(&bbox);
+                    let filename = format!("Arnis {}.mcworld", area_name);
+                    let lvl_name = format!("Arnis World: {}", area_name);
+                    let output_path = std::env::current_dir()
+                        .unwrap_or_else(|_| PathBuf::from("."))
+                        .join(filename);
+                    (output_path, Some(lvl_name))
+                }
             };
 
-            // Create an Args instance with the chosen bounding box and world directory path
+            // Calculate MC spawn coordinates from lat/lng if spawn point was provided
+            let mc_spawn_point: Option<(i32, i32)> = if let Some((lat, lng)) = spawn_point {
+                if let Ok(llpoint) = LLPoint::new(lat, lng) {
+                    if let Ok((transformer, _)) =
+                        CoordTransformer::llbbox_to_xzbbox(&bbox, world_scale)
+                    {
+                        let xzpoint = transformer.transform_point(llpoint);
+                        Some((xzpoint.x, xzpoint.z))
+                    } else {
+                        None
+                    }
+                } else {
+                    None
+                }
+            } else {
+                None
+            };
+
+            // Create generation options
+            let generation_options = GenerationOptions {
+                path: generation_path.clone(),
+                format: world_format,
+                level_name,
+                spawn_point: mc_spawn_point,
+            };
+
+            // Create an Args instance with the chosen bounding box
+            // Note: path is used for Java-specific features like spawn point update
             let args: Args = Args {
                 bbox,
                 file: None,
                 save_json_file: None,
-                path: updated_world_path,
+                path: if world_format == WorldFormat::JavaAnvil {
+                    generation_path
+                } else {
+                    world_path
+                },
                 downloader: "requests".to_string(),
                 scale: world_scale,
                 ground_level,
@@ -763,11 +977,48 @@ fn gui_start_generation(
                 roof: roof_enabled,
                 fillground: fillground_enabled,
                 debug: false,
-                timeout: Some(std::time::Duration::from_secs(floodfill_timeout)),
+                timeout: Some(std::time::Duration::from_secs(40)),
                 spawn_point,
             };
 
-            // Run data fetch and world generation
+            // If skip_osm_objects is true (terrain-only mode), skip fetching and processing OSM data
+            if skip_osm_objects {
+                // Generate ground data (terrain) for terrain-only mode
+                let ground = ground::generate_ground_data(&args);
+
+                // Create empty parsed_elements and xzbbox for terrain-only mode
+                let parsed_elements = Vec::new();
+                let (_coord_transformer, xzbbox) =
+                    CoordTransformer::llbbox_to_xzbbox(&args.bbox, args.scale)
+                        .map_err(|e| format!("Failed to create coordinate transformer: {}", e))?;
+
+                let _ = data_processing::generate_world_with_options(
+                    parsed_elements,
+                    xzbbox.clone(),
+                    args.bbox,
+                    ground,
+                    &args,
+                    generation_options.clone(),
+                );
+                // Explicitly release session lock before showing Done message
+                // so Minecraft can open the world immediately
+                drop(_session_lock);
+                emit_gui_progress_update(100.0, "Done! World generation completed.");
+                println!("{}", "Done! World generation completed.".green().bold());
+
+                // Start map preview generation silently in background (Java only)
+                if world_format == WorldFormat::JavaAnvil {
+                    let preview_info = data_processing::MapPreviewInfo::new(
+                        generation_options.path.clone(),
+                        &xzbbox,
+                    );
+                    data_processing::start_map_preview_generation(preview_info);
+                }
+
+                return Ok(());
+            }
+
+            // Run data fetch and world generation (standard mode: objects + terrain, or objects only)
             match retrieve_data::fetch_data_from_overpass(args.bbox, args.debug, "requests", None) {
                 Ok(raw_data) => {
                     let (mut parsed_elements, mut xzbbox) =
@@ -794,8 +1045,29 @@ fn gui_start_generation(
                         &mut ground,
                     );
 
-                    let _ = data_processing::generate_world(parsed_elements, xzbbox, ground, &args);
-                    // Session lock will be automatically released when _session_lock goes out of scope
+                    let _ = data_processing::generate_world_with_options(
+                        parsed_elements,
+                        xzbbox.clone(),
+                        args.bbox,
+                        ground,
+                        &args,
+                        generation_options.clone(),
+                    );
+                    // Explicitly release session lock before showing Done message
+                    // so Minecraft can open the world immediately
+                    drop(_session_lock);
+                    emit_gui_progress_update(100.0, "Done! World generation completed.");
+                    println!("{}", "Done! World generation completed.".green().bold());
+
+                    // Start map preview generation silently in background (Java only)
+                    if world_format == WorldFormat::JavaAnvil {
+                        let preview_info = data_processing::MapPreviewInfo::new(
+                            generation_options.path.clone(),
+                            &xzbbox,
+                        );
+                        data_processing::start_map_preview_generation(preview_info);
+                    }
+
                     Ok(())
                 }
                 Err(e) => {

src/gui/css/bbox.css

@@ -344,4 +344,38 @@ body,
   filter: blur(1px) sepia(1) invert(1);
   transition: all 1s ease;
 
+}
+
+/* World Preview Button in Edit Toolbar */
+.leaflet-draw-toolbar .leaflet-draw-edit-preview {
+  background-position: -31px -2px;
+}
+
+.leaflet-draw-toolbar .leaflet-draw-edit-preview.disabled {
+  opacity: 0.4;
+  cursor: not-allowed;
+  pointer-events: none;
+}
+
+.leaflet-draw-toolbar .leaflet-draw-edit-preview.active {
+  background-color: #a0d0ff;
+}
+
+.world-preview-slider-container {
+  padding: 6px 8px !important;
+  background: white !important;
+  background-clip: padding-box;
+}
+
+.world-preview-slider-container a {
+  display: none !important;
+}
+
+.world-preview-slider {
+  width: 80px;
+  height: 8px;
+  cursor: pointer;
+  accent-color: #3887BE;
+  display: block;
+  margin: 0;
 }

src/gui/css/maps/leaflet.draw.css

@@ -158,12 +158,13 @@
 	background-position: -182px -2px;
 }
 
+/* Disabled states reuse same sprites; opacity indicates disabled */
 .leaflet-draw-toolbar .leaflet-draw-edit-edit.leaflet-disabled {
-	background-position: -212px -2px;
+	background-position: -152px -2px;
 }
 
 .leaflet-draw-toolbar .leaflet-draw-edit-remove.leaflet-disabled {
-	background-position: -242px -2px;
+	background-position: -182px -2px;
 }
 
 /* ================================================================== */

src/gui/css/styles.css

@@ -63,6 +63,7 @@ a:hover {
   justify-content: center;
   align-items: stretch;
   margin-top: 5px;
+  min-height: 60vh;
 }
 
 .section {
@@ -79,6 +80,12 @@ a:hover {
   padding: 20px;
   border-radius: 8px;
   box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
+  display: flex;
+  flex-direction: column;
+}
+
+.map-box {
+  min-height: 400px;
 }
 
 .controls-content {
@@ -94,6 +101,8 @@ a:hover {
 .map-container {
   border: 2px solid #e0e0e0;
   border-radius: 8px;
+  flex-grow: 1;
+  min-height: 300px;
 }
 
 .section h2 {
@@ -213,6 +222,68 @@ button:hover {
   width: 100%;
 }
 
+/* World Selection Container */
+.world-selection-container {
+  width: 100%;
+}
+
+.choose-world-btn {
+  padding: 10px;
+  line-height: 1.2;
+  width: 100%;
+  border-radius: 8px 8px 0 0 !important;
+  margin-bottom: 0 !important;
+  box-shadow: none !important;
+}
+
+/* World Format Toggle */
+.format-toggle-container {
+  display: flex;
+  width: 100%;
+  gap: 0;
+  margin-top: 0;
+}
+
+.format-toggle-btn {
+  flex: 1;
+  padding: 10px;
+  font-size: 1em;
+  font-weight: 500;
+  border: 1px solid transparent;
+  cursor: pointer;
+  transition: all 0.25s ease;
+  margin-top: 0;
+  border-radius: 0;
+}
+
+.format-toggle-btn:first-child {
+  border-radius: 0 0 0 8px;
+}
+
+.format-toggle-btn:last-child {
+  border-radius: 0 0 8px 0;
+}
+
+.format-toggle-btn:not(.format-active) {
+  background-color: #3a3a3a;
+  color: #b0b0b0;
+}
+
+.format-toggle-btn:not(.format-active):hover {
+  background-color: #4a4a4a;
+  color: #ffffff;
+}
+
+.format-toggle-btn.format-active {
+  background-color: var(--primary-accent);
+  color: #0f0f0f;
+  font-weight: 600;
+}
+
+.format-toggle-btn.format-active:hover {
+  background-color: var(--primary-accent-dark);
+}
+
 /* Customization Settings */
 .modal {
   position: fixed;
@@ -249,6 +320,33 @@ button:hover {
   color: #ffffff;
 }
 
+/* Modal actions/buttons */
+.modal-actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: 10px;
+}
+
+.btn-primary {
+  background-color: var(--primary-accent);
+  color: #1a1a1a;
+}
+
+.btn-primary:hover {
+  background-color: var(--primary-accent-dark);
+}
+
+.btn-secondary {
+  background-color: #e0e0e0;
+}
+
+@media (prefers-color-scheme: dark) {
+  .btn-secondary {
+    background-color: #3a3a3a;
+    color: #ffffff;
+  }
+}
+
 #terrain-toggle {
   accent-color: #fecc44;
 }
@@ -281,6 +379,10 @@ button:hover {
   margin: 15px 0;
 }
 
+#telemetry-toggle {
+  accent-color: #fecc44;
+}
+
 .scale-slider-container label {
   display: block;
   margin-bottom: 5px;
@@ -306,7 +408,7 @@ button:hover {
 
 #bbox-coords {
   width: 100%;
-  padding: 8px;
+  padding: 5px;
   border: 1px solid #fecc44;
   border-radius: 4px;
   font-size: 14px;
@@ -353,7 +455,7 @@ button:hover {
 
 .license-button-row {
   justify-content: center;
-  margin-top: 10px;
+  margin-top: 5px;
 }
 
 .license-button {
@@ -389,11 +491,39 @@ button:hover {
   box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
 }
 
+/* Generation mode dropdown styling */
+.generation-mode-dropdown {
+  width: 100%;
+  max-width: 180px;
+  padding: 3px 8px;
+  border-radius: 4px;
+  border: 1px solid #fecc44;
+  background-color: #ffffff;
+  color: #0f0f0f;
+  appearance: menulist;
+  cursor: pointer;
+  font-size: 15px;
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
+}
+
+.generation-mode-dropdown option {
+  padding: 5px;
+  font-size: 15px;
+}
+
+@media (prefers-color-scheme: dark) {
+  .generation-mode-dropdown {
+    background-color: #0f0f0f98;
+    color: #ffffff;
+    border: 1px solid #fecc44;
+  }
+}
+
 /* Language dropdown styling */
 .language-dropdown {
   width: 100%;
   max-width: 180px;
-  padding: 5px 8px;
+  padding: 3px 8px;
   border-radius: 4px;
   border: 1px solid #fecc44;
   background-color: #ffffff;
@@ -421,7 +551,7 @@ button:hover {
 .theme-dropdown {
   width: 100%;
   max-width: 180px;
-  padding: 5px 8px;
+  padding: 3px 8px;
   border-radius: 4px;
   border: 1px solid #fecc44;
   background-color: #ffffff;

src/gui/index.html

@@ -14,7 +14,7 @@
 <body>
   <main class="container">
     <div class="row">
-      <a href="https://github.com/louis-e/arnis" target="_blank">
+      <a href="https://arnismc.com" target="_blank">
         <img src="./images/logo.png" id="arnis-logo" class="logo arnis" alt="Arnis Logo" style="width: 35%; height: auto;">
       </a>
     </div>
@@ -37,15 +37,26 @@
         <div class="controls-content">
           <h2 data-localize="select_world">Select World</h2>
 
-          <!-- Updated Tooltip Structure -->
-          <div class="tooltip" style="width: 100%;">
-            <button type="button" onclick="openWorldPicker()" style="padding: 10px; line-height: 1.2; width: 100%;">
-              <span id="choose_world">Choose World</span>
-              <br>
-              <span id="selected-world" style="font-size: 0.8em; color: #fecc44; display: block; margin-top: 4px;" data-localize="no_world_selected">
-                No world selected
-              </span>
-            </button>
+          <!-- World Selection Container -->
+          <div class="world-selection-container">
+            <div class="tooltip" style="width: 100%;">
+              <button type="button" id="choose-world-btn" onclick="openWorldPicker()" class="choose-world-btn">
+                <span id="choose_world">Choose World</span>
+                <br>
+                <span id="selected-world" style="font-size: 0.8em; color: #fecc44; display: block; margin-top: 4px;" data-localize="no_world_selected">
+                  No world selected
+                </span>
+              </button>
+            </div>
+            <!-- World Format Toggle -->
+            <div class="format-toggle-container">
+              <button type="button" id="format-java" class="format-toggle-btn format-active" onclick="setWorldFormat('java')">
+                Java
+              </button>
+              <button type="button" id="format-bedrock" class="format-toggle-btn" onclick="setWorldFormat('bedrock')">
+                Bedrock
+              </button>
+            </div>
           </div>
           
           <div class="button-container">
@@ -87,11 +98,15 @@
         <span class="close-button" onclick="closeSettings()">&times;</span>
         <h2 data-localize="customization_settings">Customization Settings</h2>
 
-        <!-- Terrain Toggle Button -->
+        <!-- Generation Mode Dropdown -->
         <div class="settings-row">
-          <label for="terrain-toggle" data-localize="terrain">Terrain</label>
+          <label for="generation-mode-select" data-localize="generation_mode">Generation Mode</label>
           <div class="settings-control">
-            <input type="checkbox" id="terrain-toggle" name="terrain-toggle" checked>
+            <select id="generation-mode-select" name="generation-mode-select" class="generation-mode-dropdown">
+              <option value="geo-terrain" data-localize="mode_geo_terrain">Objects + Terrain</option>
+              <option value="geo-only" data-localize="mode_geo_only">Objects only</option>
+              <option value="terrain-only" data-localize="mode_terrain_only">Terrain only</option>
+            </select>
           </div>
         </div>
 
@@ -136,14 +151,6 @@
           </div>
         </div>
 
-        <!-- Floodfill Timeout Input -->
-        <div class="settings-row">
-          <label for="floodfill-timeout" data-localize="floodfill_timeout">Floodfill Timeout (sec)</label>
-          <div class="settings-control">
-            <input type="number" id="floodfill-timeout" name="floodfill-timeout" min="0" step="1" value="20" placeholder="Seconds">
-          </div>
-        </div>
-
         <!-- Map Theme Selector -->
         <div class="settings-row">
           <label for="tile-theme-select" data-localize="map_theme">Map Theme</label>
@@ -171,6 +178,7 @@
               <option value="zh-CN">中文 (简体)</option>
               <option value="ko">한국어</option>
               <option value="pl">Polski</option>
+              <option value="lv">Latviešu</option>
               <option value="sv">Svenska</option>
               <option value="ar">العربية</option>
               <option value="fi">Suomi</option>
@@ -181,6 +189,14 @@
           </div>
         </div>
 
+        <!-- Telemetry Consent Toggle -->
+        <div class="settings-row">
+          <label for="telemetry-toggle">Anonymous Crash Reports</label>
+          <div class="settings-control">
+            <input type="checkbox" id="telemetry-toggle" name="telemetry-toggle">
+          </div>
+        </div>
+
         <!-- License and Credits Button -->
         <div class="settings-row license-button-row">
           <button type="button" id="license-button" class="license-button" onclick="openLicense()" data-localize="license_and_credits">License and Credits</button>
@@ -198,6 +214,22 @@
       </div>
     </div>
 
+    <!-- Telemetry Consent Modal (first run) -->
+    <div id="telemetry-modal" class="modal" style="display: none;">
+      <div class="modal-content">
+        <span class="close-button" onclick="rejectTelemetry()">&times;</span>
+        <h2>Help improve Arnis</h2>
+        <p style="text-align:left; margin-top:6px; color:#ececec;">
+          We’d like to collect anonymous usage data like crashes and performance to make Arnis more stable and faster.
+          <a href="https://arnismc.com/privacypolicy.html" style="color: inherit;" target="_blank">No personal data or world contents are collected.</a>
+        </p>
+        <div class="modal-actions" style="margin-top:14px;">
+          <button type="button" class="btn-secondary" onclick="rejectTelemetry()">No thanks</button>
+          <button type="button" class="btn-primary" onclick="acceptTelemetry()">Allow anonymous data</button>
+        </div>
+      </div>
+    </div>
+
     <!-- License Modal -->
     <div id="license-modal" class="modal" style="display: none;">
       <div class="modal-content">

src/gui/js/bbox.js

@@ -529,7 +529,7 @@ $(document).ready(function () {
                 failureCount++;
 
                 // After a few failures, try HTTP fallback
-                if (failureCount >= 3 && !this._httpFallbackAttempted && theme.url.startsWith('https://')) {
+                if (failureCount >= 6 && !this._httpFallbackAttempted && theme.url.startsWith('https://')) {
                     console.log('HTTPS tile loading failed, attempting HTTP fallback for', themeKey);
                     this._httpFallbackAttempted = true;
 
@@ -558,11 +558,208 @@ $(document).ready(function () {
     var savedTheme = localStorage.getItem('selectedTileTheme') || 'osm';
     changeTileTheme(savedTheme);
 
-    // Listen for theme changes from parent window (settings modal)
+    // World overlay state
+    var worldOverlay = null;
+    var worldOverlayData = null;
+    var worldOverlayEnabled = false;
+    var worldPreviewAvailable = false;
+    var sliderControl = null;
+
+    // Create the opacity slider as a proper Leaflet control
+    var SliderControl = L.Control.extend({
+        options: { position: 'topleft' },
+        onAdd: function(map) {
+            var container = L.DomUtil.create('div', 'leaflet-bar world-preview-slider-container');
+            container.id = 'world-preview-slider-container';
+            container.style.display = 'none';
+
+            var slider = L.DomUtil.create('input', 'world-preview-slider', container);
+            slider.type = 'range';
+            slider.min = '0';
+            slider.max = '100';
+            slider.value = '50';
+            slider.id = 'world-preview-opacity';
+            slider.title = 'Overlay Opacity';
+
+            L.DomEvent.on(slider, 'input', function(e) {
+                if (worldOverlay) {
+                    worldOverlay.setOpacity(e.target.value / 100);
+                }
+            });
+
+            // Prevent all map interactions
+            L.DomEvent.disableClickPropagation(container);
+            L.DomEvent.disableScrollPropagation(container);
+            L.DomEvent.on(container, 'mousedown', L.DomEvent.stopPropagation);
+            L.DomEvent.on(container, 'touchstart', L.DomEvent.stopPropagation);
+            L.DomEvent.on(slider, 'mousedown', L.DomEvent.stopPropagation);
+            L.DomEvent.on(slider, 'touchstart', L.DomEvent.stopPropagation);
+
+            return container;
+        }
+    });
+
+    // Function to add world preview button to the draw control's edit toolbar
+    function addWorldPreviewToEditToolbar() {
+        // Find the edit toolbar (contains Edit layers and Delete layers buttons)
+        var editToolbar = document.querySelector('.leaflet-draw-toolbar:not(.leaflet-draw-toolbar-top)');
+        if (!editToolbar) {
+            // Try finding by the edit/delete buttons
+            var deleteBtn = document.querySelector('.leaflet-draw-edit-remove');
+            if (deleteBtn) {
+                editToolbar = deleteBtn.parentElement;
+            }
+        }
+
+        if (editToolbar) {
+            // Create the preview button
+            var toggleBtn = document.createElement('a');
+            toggleBtn.className = 'leaflet-draw-edit-preview disabled';
+            toggleBtn.href = '#';
+            toggleBtn.title = 'Show World Preview (not available yet)';
+            toggleBtn.id = 'world-preview-btn';
+
+            toggleBtn.addEventListener('click', function(e) {
+                e.preventDefault();
+                e.stopPropagation();
+                if (worldPreviewAvailable) {
+                    toggleWorldOverlay();
+                }
+            });
+
+            editToolbar.appendChild(toggleBtn);
+
+            // Add the slider control to the map
+            sliderControl = new SliderControl();
+            map.addControl(sliderControl);
+        }
+    }
+
+    // Toggle world overlay function
+    function toggleWorldOverlay() {
+        if (!worldPreviewAvailable || !worldOverlayData) return;
+
+        worldOverlayEnabled = !worldOverlayEnabled;
+        var btn = document.getElementById('world-preview-btn');
+        var sliderContainer = document.getElementById('world-preview-slider-container');
+
+        if (worldOverlayEnabled) {
+            // Show overlay
+            var data = worldOverlayData;
+            var bounds = L.latLngBounds(
+                [data.min_lat, data.min_lon],
+                [data.max_lat, data.max_lon]
+            );
+
+            if (worldOverlay) {
+                map.removeLayer(worldOverlay);
+            }
+
+            var opacity = document.getElementById('world-preview-opacity');
+            var opacityValue = opacity ? opacity.value / 100 : 0.5;
+
+            worldOverlay = L.imageOverlay(data.image_base64, bounds, {
+                opacity: opacityValue,
+                interactive: false,
+                zIndex: 500
+            });
+            worldOverlay.addTo(map);
+
+            if (btn) {
+                btn.classList.add('active');
+                btn.title = 'Hide World Preview';
+            }
+            if (sliderContainer) {
+                sliderContainer.style.display = 'block';
+            }
+        } else {
+            // Hide overlay
+            if (worldOverlay) {
+                map.removeLayer(worldOverlay);
+                worldOverlay = null;
+            }
+            if (btn) {
+                btn.classList.remove('active');
+                btn.title = 'Show World Preview';
+            }
+            if (sliderContainer) {
+                sliderContainer.style.display = 'none';
+            }
+        }
+    }
+
+    // Enable the preview button when data is available
+    function enableWorldPreview(data) {
+        worldOverlayData = data;
+        worldPreviewAvailable = true;
+        var btn = document.getElementById('world-preview-btn');
+        if (btn) {
+            btn.classList.remove('disabled');
+            btn.title = 'Show World Preview';
+        }
+    }
+
+    // Disable and reset preview (when world changes)
+    function disableWorldPreview() {
+        worldPreviewAvailable = false;
+        worldOverlayData = null;
+        worldOverlayEnabled = false;
+
+        if (worldOverlay) {
+            map.removeLayer(worldOverlay);
+            worldOverlay = null;
+        }
+
+        var btn = document.getElementById('world-preview-btn');
+        var sliderContainer = document.getElementById('world-preview-slider-container');
+        if (btn) {
+            btn.classList.add('disabled');
+            btn.classList.remove('active');
+            btn.title = 'Show World Preview (not available yet)';
+        }
+        if (sliderContainer) {
+            sliderContainer.style.display = 'none';
+        }
+    }
+
+    // Listen for messages from parent window
     window.addEventListener('message', function(event) {
         if (event.data && event.data.type === 'changeTileTheme') {
             changeTileTheme(event.data.theme);
         }
+
+        // Handle world preview data ready (after generation completes)
+        if (event.data && event.data.type === 'worldPreviewReady') {
+            enableWorldPreview(event.data.data);
+
+            // Auto-enable the overlay when generation completes
+            if (!worldOverlayEnabled) {
+                toggleWorldOverlay();
+            }
+        }
+
+        // Handle existing world map load (zoom to location and auto-enable)
+        if (event.data && event.data.type === 'loadExistingWorldMap') {
+            var data = event.data.data;
+            enableWorldPreview(data);
+
+            // Calculate bounds and zoom to them
+            var bounds = L.latLngBounds(
+                [data.min_lat, data.min_lon],
+                [data.max_lat, data.max_lon]
+            );
+            map.fitBounds(bounds, { padding: [50, 50] });
+
+            // Auto-enable the overlay
+            if (!worldOverlayEnabled) {
+                toggleWorldOverlay();
+            }
+        }
+
+        // Handle world changed (disable preview)
+        if (event.data && event.data.type === 'worldChanged') {
+            disableWorldPreview();
+        }
     });
 
     // Set the dropdown value in parent window if it exists
@@ -652,6 +849,9 @@ $(document).ready(function () {
         }
     });
     map.addControl(drawControl);
+
+    // Add world preview button to the edit toolbar after drawControl is added
+    addWorldPreviewToEditToolbar();
     /*
     **
     **  create bounds layer
@@ -699,6 +899,15 @@ $(document).ready(function () {
             });
         }
 
+        // If it's a rectangle, remove any existing rectangles first
+        if (e.layerType === 'rectangle') {
+            drawnItems.eachLayer(function(layer) {
+                if (layer instanceof L.Rectangle) {
+                    drawnItems.removeLayer(layer);
+                }
+            });
+        }
+
         // Check if it's a rectangle and set proper styles before adding it to the layer
         if (e.layerType === 'rectangle') {
             e.layer.setStyle({