Files
sbox-public/engine/Sandbox.Engine/Scene/Components/Mesh/PolygonMesh.Serialize.cs
2026-07-20 16:31:02 +01:00

361 lines
12 KiB
C#

using System.IO;
using System.IO.Compression;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text.Json;
namespace Sandbox;
public partial class PolygonMesh
{
public static object JsonRead( ref Utf8JsonReader reader, Type typeToConvert )
{
if ( reader.TokenType != JsonTokenType.StartObject )
throw new JsonException();
var mesh = new PolygonMesh();
var topology = mesh.Topology;
var hasTextureCoords = false;
while ( reader.Read() )
{
if ( reader.TokenType == JsonTokenType.EndObject )
{
if ( !hasTextureCoords )
{
mesh.ComputeFaceTextureCoordinatesFromParameters();
}
else
{
mesh.ComputeFaceTextureParametersFromCoordinates();
}
mesh.IsDirty = true;
return mesh;
}
if ( reader.TokenType == JsonTokenType.PropertyName )
{
var propertyName = reader.GetString();
reader.Read();
if ( propertyName == "Data" )
{
var blob = reader.TokenType == JsonTokenType.String
? MeshBlob.FromBytes( reader.GetBytesFromBase64() )
: Json.Deserialize<MeshBlob>( ref reader );
if ( blob is not null )
{
blob.ApplyTo( mesh );
hasTextureCoords = blob.TextureCoord.Length > 0;
}
}
// Legacy: Position/Rotation are no longer written. They were world-space values
// that got overwritten by MeshComponent on enable. Kept for backward compat with
// old data that may not have TextureCoord and needs these to reconstruct UVs.
else if ( propertyName == "Position" )
mesh._transform = mesh.Transform.WithPosition( JsonSerializer.Deserialize<Vector3>( ref reader ) );
else if ( propertyName == "Rotation" )
mesh._transform = mesh.Transform.WithRotation( JsonSerializer.Deserialize<Rotation>( ref reader ) );
else if ( propertyName == nameof( Positions ) )
mesh.Positions.CopyFrom( JsonSerializer.Deserialize<Vector3[]>( ref reader ) );
else if ( propertyName == nameof( Blends ) )
mesh.Blends.CopyFrom( JsonSerializer.Deserialize<Color32[]>( ref reader ) );
else if ( propertyName == nameof( Colors ) )
mesh.Colors.CopyFrom( JsonSerializer.Deserialize<Color32[]>( ref reader ) );
else if ( propertyName == "TextureOrigin" )
{
if ( reader.TokenType == JsonTokenType.StartArray )
{
mesh.TextureOriginUnused.CopyFrom( JsonSerializer.Deserialize<Vector3[]>( ref reader ) );
}
else
{
JsonSerializer.Deserialize<Vector3>( ref reader );
}
}
else if ( propertyName == nameof( TextureCoord ) )
{
mesh.TextureCoord.CopyFrom( JsonSerializer.Deserialize<Vector2[]>( ref reader ) );
hasTextureCoords = true;
}
else if ( propertyName == "TextureRotation" )
mesh.TextureRotationUnused.CopyFrom( JsonSerializer.Deserialize<Rotation[]>( ref reader ) );
// Legacy: Texture parameters are no longer written. They are world-space derived
// values recomputed at runtime from TextureCoord via ComputeFaceTextureParametersFromCoordinates().
// Kept for backward compat with old data that lacks TextureCoord.
else if ( propertyName == nameof( TextureUAxis ) )
mesh.TextureUAxis.CopyFrom( JsonSerializer.Deserialize<Vector3[]>( ref reader ) );
else if ( propertyName == nameof( TextureVAxis ) )
mesh.TextureVAxis.CopyFrom( JsonSerializer.Deserialize<Vector3[]>( ref reader ) );
else if ( propertyName == nameof( TextureScale ) )
mesh.TextureScale.CopyFrom( JsonSerializer.Deserialize<Vector2[]>( ref reader ) );
else if ( propertyName == nameof( TextureOffset ) )
mesh.TextureOffset.CopyFrom( JsonSerializer.Deserialize<Vector2[]>( ref reader ) );
else if ( propertyName == "TextureAngle" )
mesh.TextureAngleUnused.CopyFrom( JsonSerializer.Deserialize<float[]>( ref reader ) );
else if ( propertyName == nameof( MaterialIndex ) )
mesh.MaterialIndex.CopyFrom( JsonSerializer.Deserialize<int[]>( ref reader ) );
else if ( propertyName == nameof( EdgeSmoothing ) )
mesh.EdgeSmoothing.CopyFrom( JsonSerializer.Deserialize<bool[]>( ref reader ) );
else if ( propertyName == nameof( EdgeFlags ) )
mesh.EdgeFlags.CopyFrom( JsonSerializer.Deserialize<int[]>( ref reader ) );
else if ( propertyName == "Materials" )
{
var materials = JsonSerializer.Deserialize<string[]>( ref reader );
mesh._materialsById.Clear();
mesh._materialIdsByName.Clear();
mesh._materialId = 0;
foreach ( var material in materials )
mesh.AddMaterial( Material.Load( material ) );
}
else if ( propertyName == nameof( mesh.Topology ) )
{
if ( reader.TokenType != JsonTokenType.String )
throw new JsonException( $"Expected a string for the '{nameof( mesh.Topology )}' property." );
try
{
using var ms = new MemoryStream( Convert.FromBase64String( reader.GetString() ) );
using var zs = new GZipStream( ms, CompressionMode.Decompress );
using var outStream = new MemoryStream();
zs.CopyTo( outStream );
outStream.Position = 0;
using var br = new BinaryReader( outStream );
topology.Deserialize( br );
}
catch
{
throw new JsonException( $"Failed to deserialize the '{nameof( mesh.Topology )}' property." );
}
}
else
{
throw new JsonException( $"Unrecognized property: {propertyName}" );
}
}
}
throw new JsonException( "JSON object did not end correctly." );
}
public static void JsonWrite( object value, Utf8JsonWriter writer )
{
if ( value is not PolygonMesh mesh )
throw new NotImplementedException();
mesh.CleanupUnusedMaterials();
writer.WriteStartObject();
// Position, Rotation, TextureUAxis, TextureVAxis, TextureScale, TextureOffset are not
// serialized because they are world-space dependent and derived at runtime.
// MeshComponent sets Mesh.Transform = WorldTransform on enable/transform change, which
// triggers ComputeFaceTextureParametersFromCoordinates() to recompute them from TextureCoord.
var blob = MeshBlob.FromMesh( mesh );
writer.WritePropertyName( "Data" );
if ( BlobDataSerializer.IsActive )
Json.Serialize( writer, blob );
else
writer.WriteBase64StringValue( blob.ToBytes() );
if ( mesh._materialsById.Count > 0 )
{
writer.WritePropertyName( "Materials" );
JsonSerializer.Serialize( writer, Enumerable.Range( 0, mesh._materialsById.Count )
.Select( x => mesh._materialsById[x] )
.Select( x => x.Name ) );
}
writer.WriteEndObject();
}
/// <summary>
/// Heavy <see cref="PolygonMesh"/> data (topology + per-element streams) serialized as a
/// single binary blob instead of verbose JSON arrays. The payload is a self describing list
/// of named sections, so individual streams can be added or removed in future versions
/// without breaking existing files: unknown sections are skipped on read and missing ones
/// keep their default (empty) value.
/// </summary>
private sealed class MeshBlob : BlobData
{
public override int Version => 1;
public byte[] Topology { get; set; } = Array.Empty<byte>();
public Vector3[] Positions { get; set; } = Array.Empty<Vector3>();
public Color32[] Blends { get; set; } = Array.Empty<Color32>();
public Color32[] Colors { get; set; } = Array.Empty<Color32>();
public Vector2[] TextureCoord { get; set; } = Array.Empty<Vector2>();
public int[] MaterialIndex { get; set; } = Array.Empty<int>();
public int[] EdgeFlags { get; set; } = Array.Empty<int>();
const string SectionTopology = "topology";
const string SectionPositions = "positions";
const string SectionBlends = "blends";
const string SectionColors = "colors";
const string SectionTextureCoord = "texcoord";
const string SectionMaterialIndex = "materialindex";
const string SectionEdgeFlags = "edgeflags";
const int SectionCount = 7;
public static MeshBlob FromMesh( PolygonMesh mesh ) => new()
{
Topology = mesh.Topology.Serialize(),
Positions = mesh.Positions.ToArray(),
Blends = mesh.Blends.ToArray(),
Colors = mesh.Colors.ToArray(),
TextureCoord = mesh.TextureCoord.ToArray(),
MaterialIndex = mesh.MaterialIndex.ToArray(),
EdgeFlags = mesh.EdgeFlags.ToArray(),
};
public void ApplyTo( PolygonMesh mesh )
{
using ( var ms = new MemoryStream( Topology ) )
using ( var br = new BinaryReader( ms ) )
{
mesh.Topology.Deserialize( br );
}
mesh.Positions.CopyFrom( Positions );
mesh.Blends.CopyFrom( Blends );
mesh.Colors.CopyFrom( Colors );
mesh.TextureCoord.CopyFrom( TextureCoord );
mesh.MaterialIndex.CopyFrom( MaterialIndex );
mesh.EdgeFlags.CopyFrom( EdgeFlags );
}
public override void Serialize( ref Writer writer )
{
ref var stream = ref writer.Stream;
stream.Write( SectionCount );
WriteSection( ref stream, SectionTopology, Topology );
WriteSection( ref stream, SectionPositions, Positions );
WriteSection( ref stream, SectionBlends, Blends );
WriteSection( ref stream, SectionColors, Colors );
WriteSection( ref stream, SectionTextureCoord, TextureCoord );
WriteSection( ref stream, SectionMaterialIndex, MaterialIndex );
WriteSection( ref stream, SectionEdgeFlags, EdgeFlags );
}
public override void Deserialize( ref Reader reader )
{
ref var stream = ref reader.Stream;
int sectionCount = stream.Read<int>();
for ( int i = 0; i < sectionCount; i++ )
{
var name = stream.Read<string>();
int byteLength = stream.Read<int>();
switch ( name )
{
case SectionTopology: Topology = ReadBytes( ref stream, byteLength ); break;
case SectionPositions: Positions = ReadSection<Vector3>( ref stream, byteLength ); break;
case SectionBlends: Blends = ReadSection<Color32>( ref stream, byteLength ); break;
case SectionColors: Colors = ReadSection<Color32>( ref stream, byteLength ); break;
case SectionTextureCoord: TextureCoord = ReadSection<Vector2>( ref stream, byteLength ); break;
case SectionMaterialIndex: MaterialIndex = ReadSection<int>( ref stream, byteLength ); break;
case SectionEdgeFlags: EdgeFlags = ReadSection<int>( ref stream, byteLength ); break;
default: stream.Position += byteLength; break;
}
}
}
static void WriteSection<T>( ref ByteStream stream, string name, ReadOnlySpan<T> data ) where T : unmanaged
{
stream.Write( name );
stream.WriteArray( MemoryMarshal.AsBytes( data ) );
}
static byte[] ReadBytes( ref ByteStream stream, int byteLength )
{
if ( byteLength <= 0 ) return Array.Empty<byte>();
var bytes = new byte[byteLength];
stream.Read( bytes, 0, byteLength );
return bytes;
}
static T[] ReadSection<T>( ref ByteStream stream, int byteLength ) where T : unmanaged
{
if ( byteLength <= 0 ) return Array.Empty<T>();
int size = Unsafe.SizeOf<T>();
if ( byteLength % size != 0 )
throw new JsonException( $"Mesh blob section is {byteLength} bytes, not a multiple of {typeof( T ).Name} ({size} bytes)" );
var result = new T[byteLength / size];
stream.Read( MemoryMarshal.AsBytes( result.AsSpan() ) );
return result;
}
public byte[] ToBytes()
{
var stream = ByteStream.Create( 4096 );
try
{
stream.Write( Version );
var writer = new Writer { Stream = stream };
Serialize( ref writer );
stream = writer.Stream;
return stream.ToArray();
}
finally
{
stream.Dispose();
}
}
public static MeshBlob FromBytes( byte[] data )
{
var blob = new MeshBlob();
var stream = ByteStream.CreateReader( data );
try
{
int dataVersion = stream.Read<int>();
var reader = new Reader { Stream = stream, DataVersion = dataVersion };
if ( dataVersion < blob.Version )
blob.Upgrade( ref reader, dataVersion );
else
blob.Deserialize( ref reader );
}
finally
{
stream.Dispose();
}
return blob;
}
}
}