Extract model loading functionality out

project/code/TMV/Mission.cs

@@ -164,25 +164,20 @@ public partial class Mission : Node3D
 
 			// Let's try and place an object :)
 			var modelName = modelNameProp.modelName + ".bin";
-			var objPath = _installPaths.GetObjectPath(_campaignName, modelName);
-
 			var pos = brush.position.ToGodotVec3();
 			var rawRot = brush.angle;
 			var rot = new Vector3(rawRot.Y, rawRot.Z, rawRot.X) * 360 / ushort.MaxValue;
 			var scale = scaleProp == null ? Vector3.One : scaleProp.scale.ToGodotVec3(false);
-			var model = new Model
+			var model = ModelLoader.LoadModel(_installPaths, _campaignName, modelName);
+			if (model != null)
 			{
-				Position = pos,
+				model.Position = pos;
-				RotationDegrees = rot,
+				model.RotationDegrees = rot;
-				Scale = scale,
+				model.Scale = scale;
-			};
-			if (objPath != null)
-			{
-				model.BuildModel("", objPath);
-			}
 				AddChild(model);
 			}
 		}
+	}
 
 	private void BuildWrMeshes(WorldRep worldRep)
 	{

project/code/TMV/ModelLoader.cs

@@ -0,0 +1,107 @@
+using System.Collections.Generic;
+using System.IO;
+using Godot;
+using KeepersCompound.LGS;
+
+namespace KeepersCompound.TMV;
+
+public static class ModelLoader
+{
+    public static MeshInstance3D LoadModel(ResourcePathManager pathManager, string campaignName, string modelName)
+    {
+        var modelPath = pathManager.GetObjectPath(campaignName, modelName);
+        if (modelPath == null)
+        {
+            return null;
+        }
+        var modelFile = new ModelFile(modelPath);
+        if (modelFile == null)
+        {
+            GD.Print($"Failed to load model file: {modelPath}");
+            return null;
+        }
+
+        // TODO: Remove this disgusting hack. Not only is it a hack, it doesn't support custom models
+        var baseDir = Path.GetDirectoryName(modelPath);
+        var options = new EnumerationOptions
+        {
+            MatchCasing = MatchCasing.CaseInsensitive,
+            RecurseSubdirectories = true,
+        };
+        var materials = new List<StandardMaterial3D>();
+        foreach (var material in modelFile.Materials)
+        {
+            if (material.Type == 0)
+            {
+                var paths = Directory.GetFiles(baseDir, material.Name, options);
+                if (paths.IsEmpty()) continue;
+
+                materials.Add(new StandardMaterial3D
+                {
+                    AlbedoTexture = TextureLoader.LoadTexture(paths[0])
+                });
+            }
+            else
+            {
+                var b = (material.Handle) & 0xff;
+                var g = (material.Handle >> 8) & 0xff;
+                var r = (material.Handle >> 16) & 0xff;
+                var colour = new Color(r / 255.0f, g / 255.0f, b / 255.0f, 1.0f);
+                materials.Add(new StandardMaterial3D
+                {
+                    AlbedoColor = colour
+                });
+            }
+        }
+
+        var surfaceDataMap = new Dictionary<int, MeshSurfaceData>();
+        foreach (var poly in modelFile.Polygons)
+        {
+            var vertices = new List<Vector3>();
+            var normal = modelFile.Normals[poly.Normal].ToGodotVec3();
+            var uvs = new List<Vector2>();
+            for (var i = 0; i < poly.VertexCount; i++)
+            {
+                var vertex = modelFile.Vertices[poly.VertexIndices[i]];
+                vertices.Add(vertex.ToGodotVec3());
+                if (i < poly.UvIndices.Length)
+                {
+                    var uv = modelFile.Uvs[poly.UvIndices[i]];
+                    uvs.Add(new Vector2(uv.X, uv.Y));
+                }
+                else
+                {
+                    uvs.Add(Vector2.Zero);
+                }
+            }
+
+            if (!surfaceDataMap.ContainsKey(poly.Data))
+            {
+                surfaceDataMap.Add(poly.Data, new MeshSurfaceData());
+            }
+
+            surfaceDataMap[poly.Data].AddPolygon(vertices, normal, uvs, uvs);
+        }
+
+        var mesh = new ArrayMesh();
+        foreach (var (materialId, surfaceData) in surfaceDataMap)
+        {
+            var array = surfaceData.BuildSurfaceArray();
+            var surfaceIdx = mesh.GetSurfaceCount();
+            mesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, array);
+            for (var i = 0; i < materials.Count; i++)
+            {
+                var m = modelFile.Materials[i];
+                if (m.Slot == materialId)
+                {
+                    mesh.SurfaceSetMaterial(surfaceIdx, materials[i]);
+                    break;
+                }
+            }
+        }
+
+        var pos = -modelFile.Header.Center.ToGodotVec3();
+        var meshInstance = new MeshInstance3D { Mesh = mesh, Position = pos };
+        return meshInstance;
+    }
+}