sbox-public/engine/Sandbox.Engine/Scene/Components/Render/TextRenderer.cs

using System.Text.Json;
using System.Text.Json.Nodes;
using Sandbox.Rendering;

namespace Sandbox;

/// <summary>
/// Renders text in the world
/// </summary>
[Expose]
[Title( "Text Renderer" )]
[Category( "Rendering" )]
[Icon( "font_download" )]
[EditorHandle( "materials/gizmo/text_renderer.png" )]
public sealed class TextRenderer : Renderer, Component.ExecuteInEditor
{
	TextSceneObject _so;

	/// <summary>
	/// Represents the horizontal alignment of the text.
	/// </summary>
	public enum HAlignment
	{
		[Icon( "align_horizontal_left" )]
		Left = 1,

		[Icon( "align_horizontal_center" )]
		Center = 2,

		[Icon( "align_horizontal_right" )]
		Right = 3,
	}

	/// <summary>
	/// Represents the vertical alignment of the text.
	/// </summary>
	public enum VAlignment
	{
		[Icon( "align_vertical_top" )]
		Top = 1,

		[Icon( "align_vertical_center" )]
		Center = 2,

		[Icon( "align_vertical_bottom" )]
		Bottom = 3,
	}

	/// <summary>
	/// The text scope defines what text to render and it's visual properties (such as font, color, outline, etc.)
	/// </summary>
	[Property]
	public TextRendering.Scope TextScope
	{
		get => _textScope;
		set
		{
			_textScope = value;

			if ( _so.IsValid() )
			{
				_so.TextScope = value;
				_so.CalculateBounds();
			}
		}
	}

	TextRendering.Scope _textScope = new( "Hello! ❤", Color.White, 32.0f, "Poppins", 400 );

	/// <summary>
	/// The size of the text in the world. This is different from the font size, which is defined in the TextScope and determines resolution of the rendered text.
	/// </summary>
	[Property, Range( 0, 2 )]
	public float Scale
	{
		get;
		set
		{
			if ( field == value ) return;
			field = value;

			TransformChanged();
		}
	} = 1.0f;

	/// <summary>
	/// The horizontal alignment of the text in the world.
	/// </summary>
	[Property]
	public HAlignment HorizontalAlignment
	{
		get;
		set
		{
			if ( field == value ) return;
			field = value;

			UpdateAlignment();

			if ( _so.IsValid() )
				_so.CalculateBounds();
		}
	} = HAlignment.Center;

	/// <summary>
	/// The vertical alignment of the text in the world.
	/// </summary>
	[Property]
	public VAlignment VerticalAlignment
	{
		get;
		set
		{
			if ( field == value ) return;
			field = value;

			UpdateAlignment();

			if ( _so.IsValid() )
				_so.CalculateBounds();
		}
	} = VAlignment.Center;

	/// <summary>
	/// Controls how the text orients itself toward the camera.
	/// </summary>
	public enum BillboardMode
	{
		/// <summary>
		/// The text uses its own world rotation.
		/// </summary>
		[Icon( "crop_din" )]
		None,

		/// <summary>
		/// The text fully rotates to face the camera, so it's always readable.
		/// </summary>
		[Icon( "filter_center_focus" )]
		Always,

		/// <summary>
		/// The text rotates around the vertical axis only, facing the camera while staying upright.
		/// </summary>
		[Icon( "360" )]
		YOnly,
	}

	/// <summary>
	/// Controls how the text orients itself toward the camera.
	/// </summary>
	[Property]
	public BillboardMode Billboard
	{
		get;
		set
		{
			if ( field == value ) return;
			field = value;

			if ( _so.IsValid() )
			{
				_so.Billboard = field;
				TransformChanged();
			}
		}
	}

	/// <summary>
	/// The blend mode of the text. This determines how the text is rendered over the world.
	/// </summary>
	[Property]
	public BlendMode BlendMode
	{
		get;
		set
		{
			if ( field == value ) return;
			field = value;

			if ( _so.IsValid() )
			{
				_so.BlendMode = value;
				_so.BuildCommandList();
			}
		}
	} = BlendMode.Normal;

	/// <summary>
	/// The strength of the fog effect applied to the text. This determines how much the text blends with any fog in the scene.
	/// </summary>
	[Property, Range( 0, 1 )]
	public float FogStrength
	{
		get;
		set
		{
			if ( field == value ) return;
			field = value;

			if ( _so.IsValid() )
			{
				_so.FogStrength = value;
				_so.BuildCommandList();
			}
		}
	} = 1.0f;

	protected override void OnEnabled()
	{
		_so = new TextSceneObject( Scene.SceneWorld )
		{
			Transform = WorldTransform.WithScale( WorldScale * Scale ),
			BlendMode = BlendMode,
			FogStrength = FogStrength,
			TextScope = TextScope,
			Billboard = Billboard,
		};

		UpdateAlignment();

		TransformChanged();

		RenderOptions.Apply( _so );

		OnSceneObjectCreated( _so );

		Transform.OnTransformChanged += TransformChanged;
	}

	protected override void OnDisabled()
	{
		Transform.OnTransformChanged -= TransformChanged;

		BackupRenderAttributes( _so?.Attributes );
		_so?.Delete();
		_so = null;
	}

	protected override void OnRenderOptionsChanged()
	{
		if ( _so.IsValid() )
		{
			RenderOptions.Apply( _so );
		}
	}

	void UpdateAlignment()
	{
		if ( !_so.IsValid() ) return;

		var vCenter = VerticalAlignment switch
		{
			VAlignment.Top => TextFlag.Top,
			VAlignment.Bottom => TextFlag.Bottom,
			_ => TextFlag.CenterVertically,
		};

		_so.TextFlags = HorizontalAlignment switch
		{
			HAlignment.Left => TextFlag.Left | vCenter | TextFlag.DontClip,
			HAlignment.Center => TextFlag.CenterHorizontally | vCenter | TextFlag.DontClip,
			HAlignment.Right => TextFlag.Right | vCenter | TextFlag.DontClip,
			_ => TextFlag.CenterHorizontally | vCenter | TextFlag.DontClip,
		};
	}

	void TransformChanged()
	{
		if ( !_so.IsValid() ) return;

		var rotation = Billboard == BillboardMode.None ? WorldRotation : Rotation.Identity;

		_so.Transform = new Transform( WorldPosition, rotation, WorldScale * Scale );
		_so.CalculateBounds();
	}

	/// <summary>
	/// Tags have been updated - lets update our scene object tags
	/// </summary>
	protected override void OnTagsChanged()
	{
		if ( !_so.IsValid() ) return;

		_so.Tags.SetFrom( GameObject.Tags );
	}

	/// <summary>
	/// The color of the text from the TextScope.
	/// </summary>
	public Color Color
	{
		get => _textScope.TextColor;
		set
		{
			_textScope.TextColor = value;

			if ( _so.IsValid() )
			{
				_so.TextScope = _textScope;
				_so.BuildCommandList();
			}
		}
	}

	/// <summary>
	/// The font size of the text from the TextScope. This is different from the Scale, which determines how large the text appears in the world.
	/// </summary>
	public float FontSize
	{
		get => _textScope.FontSize;
		set
		{
			_textScope.FontSize = value;

			if ( _so.IsValid() )
			{
				_so.TextScope = _textScope;
				_so.CalculateBounds();
			}
		}
	}
	public int FontWeight
	{
		get => _textScope.FontWeight;
		set
		{
			_textScope.FontWeight = value;

			if ( _so.IsValid() )
			{
				_so.TextScope = _textScope;
				_so.CalculateBounds();
			}
		}
	}

	public string FontFamily
	{
		get => _textScope.FontName;
		set
		{
			_textScope.FontName = value;

			if ( _so.IsValid() )
			{
				_so.TextScope = _textScope;
				_so.CalculateBounds();
			}
		}
	}

	public string Text
	{
		get => _textScope.Text;
		set
		{
			_textScope.Text = value;

			if ( _so.IsValid() )
			{
				_so.TextScope = _textScope;
				_so.CalculateBounds();
			}
		}
	}

	public override int ComponentVersion => 2;

	[Expose, JsonUpgrader( typeof( TextRenderer ), 1 )]
	static void Upgrader_v1( JsonObject obj )
	{
		// shouldn't be nessecary
		if ( obj.ContainsKey( "TextScope" ) )
		{
			Log.Info( "Skipping - has TextScope" );
			return;
		}

		var ts = new TextRendering.Scope( "Hello! ❤", Color.White, 32.0f, "Poppins", 800 );

		ts.TextColor = obj.GetPropertyValue( "Color", ts.TextColor );
		ts.FontSize = obj.GetPropertyValue( "FontSize", ts.FontSize );
		ts.FontWeight = obj.GetPropertyValue( "FontWeight", ts.FontWeight );
		ts.FontName = obj.GetPropertyValue( "FontFamily", ts.FontName );
		ts.Text = obj.GetPropertyValue( "Text", ts.Text );

		obj["TextScope"] = JsonSerializer.SerializeToNode( ts );
	}

	[Expose, JsonUpgrader( typeof( TextRenderer ), 2 )]
	static void Upgrader_v2( JsonObject obj )
	{
		if ( obj["TextScope"] is JsonObject scope && !scope.ContainsKey( "FilterMode" ) )
		{
			scope["FilterMode"] = "Bilinear";
		}
	}

	class TextSceneObject : SceneCustomObject
	{
		public TextFlag TextFlags { get; set; } = TextFlag.DontClip | TextFlag.Center;
		public BlendMode BlendMode { get; set; } = BlendMode.Normal;
		public float FogStrength { get; set; } = 1.0f;
		public BillboardMode Billboard { get; set; }

		private readonly CommandList _commandList = new( "TextRenderer" );

		private TextRendering.Scope _textScope;
		public TextRendering.Scope TextScope
		{
			get => _textScope;
			set
			{
				_textScope = value;

				var text = _textScope.Text;

				if ( !string.IsNullOrWhiteSpace( text ) && text.Length > 1 && text[0] == '#' )
				{
					var token = text[1..];
					text = Game.Language.GetPhrase( token );

					if ( text != token )
					{
						_textScope.Text = text;
					}
				}
			}
		}

		public TextSceneObject( SceneWorld world ) : base( world )
		{
			RenderLayer = SceneRenderLayer.Default;
		}

		static readonly Matrix PanelMatrix = Matrix.CreateRotation( Rotation.From( 0, -90, 90 ) );

		public void BuildCommandList()
		{
			_commandList.Reset();

			if ( string.IsNullOrWhiteSpace( TextScope.Text ) )
				return;

			_commandList.Attributes.SetCombo( "D_WORLDPANEL", 1 );
			_commandList.Attributes.SetCombo( "D_BLENDMODE", BlendMode );
			_commandList.Attributes.Set( "g_FogStrength", FogStrength );
			_commandList.DrawText( TextScope, new Rect( 0 ), TextFlags );
		}

		public override void RenderSceneObject()
		{
			var worldMat = PanelMatrix;

			if ( Billboard != BillboardMode.None )
			{
				var forward = Transform.Position - Graphics.CameraPosition;
				var up = Graphics.CameraRotation.Up;

				if ( Billboard == BillboardMode.YOnly )
				{
					forward = forward.WithZ( 0 );
					up = Vector3.Up;
				}

				if ( forward.IsNearZeroLength )
					return;

				worldMat = Matrix.CreateWorld( Vector3.Zero, forward.Normal, up );
			}

			Graphics.Attributes.Set( "WorldMat", worldMat );
			_commandList.ExecuteOnRenderThread();
		}

		public void CalculateBounds()
		{
			if ( string.IsNullOrWhiteSpace( TextScope.Text ) )
			{
				LocalBounds = BBox.FromPositionAndSize( 0, 1 );
				return;
			}

			var tx = Transform;
			var scale = tx.Scale;
			var x = Graphics.MeasureText( new Rect( 0 ), TextScope, TextFlags );
			var center = new Vector3( 0.0f,
				TextFlags.Contains( TextFlag.Right ) ? x.Width * 0.5f :
				TextFlags.Contains( TextFlag.Left ) ? -x.Width * 0.5f : 0.0f,
				TextFlags.Contains( TextFlag.Bottom ) ? x.Height * 0.5f :
				TextFlags.Contains( TextFlag.Top ) ? -x.Height * 0.5f : 0.0f );

			var bounds = BBox.FromPositionAndSize( center * scale, new Vector3( 2, x.Width * scale.y, x.Height * scale.z ) );

			if ( Billboard != BillboardMode.None )
			{
				var radius = (center * scale).Length + bounds.Size.Length * 0.5f;
				Bounds = BBox.FromPositionAndSize( tx.Position, radius * 2.0f );
			}
			else
			{
				Bounds = bounds.Transform( tx.WithScale( 1 ) );
			}

			BuildCommandList();
		}
	}
}