Split meshes into a surface for each poly

project/code/Mission.cs

@@ -1,4 +1,5 @@
 using Godot;
+using Godot.NativeInterop;
 using KeepersCompound.LGS;
 using KeepersCompound.LGS.Database;
 using KeepersCompound.LGS.Database.Chunks;
@@ -102,35 +103,26 @@ public partial class Mission : Node3D
 		// You'd think these would be the same number, but apparently not
 		// I think it's because water counts as a render poly and a portal poly
 		var maxPolyIdx = Math.Min(numRenderPolys, numPolys - numPortalPolys);
+		var surfaceArrays = BuildSurfaceArrays(cell, maxPolyIdx, out var packingRects);
 
-		var packingRects = new PackingRectangle[maxPolyIdx];
+		Image lightmap = BuildLightmap(cell, packingRects, surfaceArrays);
-		var rectIdToUvIdxMap = new List<int[]>();
-
-		var vertices = new List<Vector3>();
-		var normals = new List<Vector3>();
-		var indices = new List<int>();
-		var lightmapUvs = new List<Vector2>();
-		GenerateMeshContent(cell, maxPolyIdx, packingRects, rectIdToUvIdxMap, vertices, normals, indices, lightmapUvs);
-
-		Image lightmap = BuildLightmap(cell, packingRects, rectIdToUvIdxMap, lightmapUvs);
-
 		var material = new StandardMaterial3D
 		{
 			AlbedoTexture = ImageTexture.CreateFromImage(lightmap),
 			TextureFilter = BaseMaterial3D.TextureFilterEnum.Nearest,
 		};
 
-		MeshInstance3D mesh = GenerateMesh(vertices, normals, indices, lightmapUvs, material);
+		MeshInstance3D mesh = GenerateMesh(surfaceArrays, material);
-		OccluderInstance3D occluderInstance = GenerateOccluder(vertices, indices);
+		// OccluderInstance3D occluderInstance = GenerateOccluder(vertices, indices);
 
 		var cellNode = new Node3D();
 		cellNode.AddChild(mesh);
-		cellNode.AddChild(occluderInstance);
+		// cellNode.AddChild(occluderInstance);
 
 		AddChild(cellNode);
 	}
 
-	private static Image BuildLightmap(WorldRep.Cell cell, PackingRectangle[] packingRects, List<int[]> rectIdToUvIdxMap, List<Vector2> lightmapUvs)
+	private static Image BuildLightmap(WorldRep.Cell cell, PackingRectangle[] packingRects, List<Godot.Collections.Array> surfaceArrays)
 	{
 		RectanglePacker.Pack(packingRects, out var bounds);
 		var image = Image.Create((int)bounds.Width, (int)bounds.Height, false, Image.Format.Rgba8);
@@ -158,10 +150,10 @@ public partial class Mission : Node3D
 			}
 
 			// Transform UVs
-			var lmUvIdxs = rectIdToUvIdxMap[rect.Id];
+			var lightmapUvs = surfaceArrays[rect.Id][(int)Mesh.ArrayType.TexUV].As<Vector2[]>();
-			foreach (var idx in lmUvIdxs)
+			for (var i = 0; i < lightmapUvs.Length; i++)
 			{
-				var uv = lightmapUvs[idx];
+				var uv = lightmapUvs[i];
 				var u = uv.X;
 				var v = uv.Y;
 
@@ -174,21 +166,31 @@ public partial class Mission : Node3D
 				// Transform!
 				u = (rect.X + rect.Width * u) / (int)bounds.Width;
 				v = (rect.Y + rect.Height * v) / (int)bounds.Height;
-				lightmapUvs[idx] = new Vector2(u, v);
+				lightmapUvs[i] = new Vector2(u, v);
 			}
+			surfaceArrays[rect.Id][(int)Mesh.ArrayType.TexUV] = lightmapUvs;
 		}
 
 		return image;
 	}
 
-	private static void GenerateMeshContent(WorldRep.Cell cell, int maxPolyIdx, PackingRectangle[] packingRects, List<int[]> rectIdToUvIdxMap, List<Vector3> vertices, List<Vector3> normals, List<int> indices, List<Vector2> lightmapUvs)
+	private static List<Godot.Collections.Array> BuildSurfaceArrays(
+		WorldRep.Cell cell,
+		int maxPolyIdx,
+		out PackingRectangle[] packingRects)
 	{
+		packingRects = new PackingRectangle[maxPolyIdx];
+
+		var surfacesArrays = new List<Godot.Collections.Array>();
 		var cellIdxOffset = 0;
 		for (int i = 0; i < maxPolyIdx; i++)
 		{
-			var poly = cell.Polys[i];
+			var vertices = new List<Vector3>();
-			var meshIdxOffset = vertices.Count;
+			var normals = new List<Vector3>();
+			var indices = new List<int>();
+			var uvs = new List<Vector2>();
 
+			var poly = cell.Polys[i];
 			var normal = cell.Planes[poly.PlaneId].Normal.ToGodotVec3();
 			var numPolyVertices = poly.VertexCount;
 			for (var j = 0; j < numPolyVertices; j++)
@@ -201,20 +203,29 @@ public partial class Mission : Node3D
 			// Simple triangulation. Polys are always convex so we can just do a fan
 			for (int j = 1; j < numPolyVertices - 1; j++)
 			{
-				indices.Add(meshIdxOffset);
+				indices.Add(0);
-				indices.Add(meshIdxOffset + j);
+				indices.Add(j);
-				indices.Add(meshIdxOffset + j + 1);
+				indices.Add(j + 1);
 			}
 
 			// UVs
 			var renderPoly = cell.RenderPolys[i];
 			var light = cell.LightList[i];
 			packingRects[i] = new PackingRectangle(0, 0, light.Width, light.Height, i);
-			var uvIdxs = CalcBaseUV(cell, poly, renderPoly, light, lightmapUvs, cellIdxOffset);
+			CalcBaseUV(cell, poly, renderPoly, light, uvs, cellIdxOffset);
-			rectIdToUvIdxMap.Add(uvIdxs);
 
 			cellIdxOffset += poly.VertexCount;
+
+			var array = new Godot.Collections.Array();
+			array.Resize((int)Mesh.ArrayType.Max);
+			array[(int)Mesh.ArrayType.Vertex] = vertices.ToArray();
+			array[(int)Mesh.ArrayType.Normal] = normals.ToArray();
+			array[(int)Mesh.ArrayType.Index] = indices.ToArray();
+			array[(int)Mesh.ArrayType.TexUV] = uvs.ToArray();
+			surfacesArrays.Add(array);
 		}
+
+		return surfacesArrays;
 	}
 
 	private static OccluderInstance3D GenerateOccluder(List<Vector3> vertices, List<int> indices)
@@ -229,18 +240,14 @@ public partial class Mission : Node3D
 		return occluderInstance;
 	}
 
-	private static MeshInstance3D GenerateMesh(List<Vector3> vertices, List<Vector3> normals, List<int> indices, List<Vector2> lightmapUvs, StandardMaterial3D material)
+	private static MeshInstance3D GenerateMesh(List<Godot.Collections.Array> surfaceArrays, StandardMaterial3D material)
 	{
 		var arrMesh = new ArrayMesh();
-		var arrays = new Godot.Collections.Array();
+		for (var i = 0; i < surfaceArrays.Count; i++)
-		arrays.Resize((int)Mesh.ArrayType.Max);
+		{
-		arrays[(int)Mesh.ArrayType.Vertex] = vertices.ToArray();
+			arrMesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, surfaceArrays[i]);
-		arrays[(int)Mesh.ArrayType.Normal] = normals.ToArray();
+			arrMesh.SurfaceSetMaterial(i, material);
-		arrays[(int)Mesh.ArrayType.Index] = indices.ToArray();
+		}
-		arrays[(int)Mesh.ArrayType.TexUV] = lightmapUvs.ToArray();
-
-		arrMesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, arrays);
-		arrMesh.SurfaceSetMaterial(0, material);
 
 		var meshInstance = new MeshInstance3D
 		{
@@ -250,7 +257,7 @@ public partial class Mission : Node3D
 		return meshInstance;
 	}
 
-	private static int[] CalcBaseUV(
+	private static void CalcBaseUV(
 		WorldRep.Cell cell,
 		WorldRep.Cell.Poly poly,
 		WorldRep.Cell.RenderPoly renderPoly,
@@ -275,15 +282,12 @@ public partial class Mission : Node3D
 		var lmVBase = lmVScale * (baseV + (0.5f - light.Bases.Item2) / 4.0f);
 		var anchor = cell.Vertices[cell.Indices[cellIdxOffset + 0]].ToGodotVec3(); // TODO: This probably shouldn't be hardcoded idx 0
 
-		var uvIdxs = new int[poly.VertexCount];
 		if (uv == 0.0)
 		{
 			var lmUVec = texU * lmUScale / uu;
 			var lmVVec = texV * lmVScale / vv;
 			for (var i = 0; i < poly.VertexCount; i++)
 			{
-				uvIdxs[i] = lightmapUvs.Count;
-
 				var v = cell.Vertices[cell.Indices[cellIdxOffset + i]].ToGodotVec3();
 				var delta = new Vector3(v.X - anchor.X, v.Y - anchor.Y, v.Z - anchor.Z);
 				var lmUV = new Vector2(delta.Dot(lmUVec) + lmUBase, delta.Dot(lmVVec) + lmVBase);
@@ -299,8 +303,6 @@ public partial class Mission : Node3D
 			var lmUvv = lmVScale * denom * uv;
 			for (var i = 0; i < poly.VertexCount; i++)
 			{
-				uvIdxs[i] = lightmapUvs.Count;
-
 				var v = cell.Vertices[cell.Indices[cellIdxOffset + i]].ToGodotVec3();
 				var delta = new Vector3(v.X - anchor.X, v.Y - anchor.Y, v.Z - anchor.Z);
 				var du = delta.Dot(texU);
@@ -309,8 +311,6 @@ public partial class Mission : Node3D
 				lightmapUvs.Add(lmUV);
 			}
 		}
-
-		return uvIdxs;
 	}
 
 	private void LoadTextures(TxList textureList)