Fix incorrect lightmap scale multiplier

project/code/LGS/Database/Chunks/WorldRep.cs

@@ -1,3 +1,4 @@
+using System;
 using System.IO;
 using System.Numerics;
 
@@ -28,6 +29,16 @@ public class WorldRep : IChunk
             DataSize = reader.ReadUInt32();
             CellCount = reader.ReadUInt32();
         }
+
+        public readonly float LightmapScaleMultiplier()
+        {
+            return Math.Sign(LightmapScale) switch
+            {
+                1 => LightmapScale,
+                -1 => 1.0f / LightmapScale,
+                _ => 1.0f,
+            };
+        }
     }
 
     public struct Cell
@@ -137,6 +148,63 @@ public class WorldRep : IChunk
                         return Vector4.Zero;
                 }
             }
+
+            public readonly byte[] AsBytesRgba()
+            {
+                var length = Width * Height * 4;
+                var bytes = new byte[length];
+                for (var i = 0; i < length; i++)
+                {
+                    bytes[i] = 0;
+                }
+
+                // TODO: might be faster to do these fors in the switch?
+                for (var z = 0; z < Layers; z++)
+                {
+                    for (var y = 0; y < Height; y++)
+                    {
+                        for (var x = 0; x < Width; x++)
+                        {
+                            var pIdx = 0 + x * Bpp + y * Bpp * Width + z * Bpp * Width * Height;
+                            var r = 0;
+                            var g = 0;
+                            var b = 0;
+                            var a = 0;
+                            switch (Bpp)
+                            {
+                                case 1:
+                                    var raw1 = Pixels[pIdx];
+                                    r = raw1;
+                                    g = raw1;
+                                    b = raw1;
+                                    a = 255;
+                                    break;
+                                case 2:
+                                    var raw2 = Pixels[pIdx] + (Pixels[pIdx + 1] << 8);
+                                    r = (int)(255 * (raw2 & 31) / 31.0f);
+                                    g = (int)(255 * ((raw2 >> 5) & 31) / 31.0f);
+                                    b = (int)(255 * ((raw2 >> 10) & 31) / 31.0f);
+                                    a = 255;
+                                    break;
+                                case 4:
+                                    r = Pixels[pIdx + 2];
+                                    g = Pixels[pIdx + 1];
+                                    b = Pixels[pIdx];
+                                    a = Pixels[pIdx + 3];
+                                    break;
+                            }
+
+                            var bIdx = x * 4 + y * 4 * Width;
+                            bytes[bIdx] = (byte)Math.Min(255, bytes[bIdx] + r);
+                            bytes[bIdx + 1] = (byte)Math.Min(255, bytes[bIdx + 1] + g);
+                            bytes[bIdx + 2] = (byte)Math.Min(255, bytes[bIdx + 2] + b);
+                            bytes[bIdx + 3] = (byte)Math.Min(255, bytes[bIdx + 3] + a);
+                        }
+                    }
+                }
+
+                return bytes;
+            }
         }
 
         public byte VertexCount { get; set; }

project/code/TMV/Mission.cs

@@ -267,7 +267,7 @@ public partial class Mission : Node3D
 
 		var renderPoly = cell.RenderPolys[polyIdx];
 		var light = cell.LightList[polyIdx];
-		var lightmapScale = worldRep.DataHeader.LightmapScale;
+		var lightmapScale = worldRep.DataHeader.LightmapScaleMultiplier();
 		var textureId = CalcBaseUV(cell, poly, renderPoly, light, textureUvs, lightmapUvs, lightmapScale, indicesOffset);
 
 		if (!surfaceDataMap.ContainsKey(textureId))
@@ -299,23 +299,8 @@ public partial class Mission : Node3D
 			if (info.cellIndex >= cells.Length) GD.Print($"CellIndex too big: {info.cellIndex}/{cells.Length}");
 			if (info.lightmapIndex >= cells[info.cellIndex].Lightmaps.Length) GD.Print($"LightmapIndex too big: {info.lightmapIndex}/{cells[info.cellIndex].Lightmaps.Length}");
 			var lightmap = cells[info.cellIndex].Lightmaps[info.lightmapIndex];
-			var layers = (uint)lightmap.Layers;
+			var cellLm = Image.CreateFromData(lightmap.Width, lightmap.Height, false, Image.Format.Rgba8, lightmap.AsBytesRgba());
-			var height = (uint)lightmap.Height;
+			image.BlitRect(cellLm, new Rect2I(0, 0, lightmap.Width, lightmap.Height), new Vector2I((int)rect.X, (int)rect.Y));
-			var width = (uint)lightmap.Width;
-			for (uint y = 0; y < height; y++)
-			{
-				for (uint x = 0; x < width; x++)
-				{
-					var rawColour = System.Numerics.Vector4.Zero;
-					for (uint l = 0; l < layers; l++)
-					{
-						rawColour += lightmap.GetPixel(l, x, y);
-					}
-
-					var colour = new Color(MathF.Min(rawColour.X, 1.0f), MathF.Min(rawColour.Y, 1.0f), MathF.Min(rawColour.Z, 1.0f), MathF.Min(rawColour.W, 1.0f));
-					image.SetPixel((int)(rect.X + x), (int)(rect.Y + y), colour);
-				}
-			}
 
 			if (!surfaceDataMap.ContainsKey(info.textureId)) GD.Print("Invalid SurfaceDataMap key");
 			surfaceDataMap[info.textureId].TransformUv2s(info.uvStart, info.uvEnd, (uv) =>