Reconstruct brush model data based on glpoly_t data generated by GLQuake. We can now successfully display BSP maps in Unity!

Assets/Scripts/Data/QExtensions.cs

@@ -30,6 +30,11 @@ public static class QExtensions
         return result;
     }
 
+    public static Vector3 ToVector2(this QVec2 vec)
+    {
+        return new Vector2(vec.x, vec.y);
+    }
+    
     public static Vector3 ToVector3(this QVec3 vec)
     {
         return new Vector3(vec.x, vec.y, vec.z);

Assets/Scripts/Data/QMath.cs

@@ -12,6 +12,13 @@ public struct QVec3
     public float z;
 }
 
+[StructLayout(LayoutKind.Sequential, Pack = 0)]
+public struct QVec2
+{
+    public float x;
+    public float y;
+}
+
 [StructLayout(LayoutKind.Sequential, Pack = 0)]
 public struct QVec4i
 {

Assets/Scripts/Data/QModel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Runtime.InteropServices;
 
 /// <summary>
@@ -221,42 +222,6 @@ public struct QSTVert
     public int s, t;
 }
 
-/// <summary>
-/// Managed equivalent of dmodel_t
-/// </summary>
-[StructLayout(LayoutKind.Sequential, Pack = 0)]
-public struct QDModel
-{
-    public QVec3 mins, maxs;
-    public QVec3 origin;
-    [MarshalAs(UnmanagedType.ByValArray, SizeConst = QConstants.MaxMapHulls)] public int[] headNode;
-    public int visLeafs;
-    public int firstFace, numFaces;
-}
-
-/// <summary>
-/// Managed equivalent of mplane_t
-/// </summary>
-[StructLayout(LayoutKind.Sequential, Pack = 0)]
-public struct QPlane
-{
-    public QVec3 normal;
-    public float dist;
-    public byte type;
-    public byte signBits;
-    public byte pad0, pad1;
-}
-
-/// <summary>
-/// Managed equivalent of medge_t
-/// </summary>
-[StructLayout(LayoutKind.Sequential, Pack = 0)]
-public struct QEdge
-{
-    public uint v0, v1;
-    public uint cachedEdgeOffset;
-}
-
 /// <summary>
 /// Managed equivalent of msurface_t
 /// </summary>
@@ -293,4 +258,42 @@ public struct QSurface
     [MarshalAs(UnmanagedType.ByValArray, SizeConst = QConstants.MaxLightmaps)] public int[] cachedLight;
     public bool cachedDLight;
     public IntPtr samples;  // Pointer to byte
+
+    public IEnumerable<QGLPolyVert[]> GetPolygons()
+    {
+        // This is so nasty. We have to deconstruct a linked list of variable-sized structs. Yuck.
+        int offset = Marshal.SizeOf<IntPtr>() * 2 + Marshal.SizeOf<int>();
+        
+        IntPtr polyPtr = polys;
+        while (polyPtr != IntPtr.Zero)
+        {
+            QGLPoly polygon = Marshal.PtrToStructure<QGLPoly>(polyPtr);
+            QGLPolyVert[] vertices = IntPtr.Add(polyPtr, offset).ToStructArray<QGLPolyVert>(polygon.numVerts);
+            yield return vertices;
+            
+            polyPtr = polygon.next;
+        }
+    }
+}
+
+/// <summary>
+/// Managed equivalent of glpoly_t
+/// </summary>
+[StructLayout(LayoutKind.Sequential, Pack = 0)]
+public struct QGLPoly
+{
+    public IntPtr next;     // Pointer to glpoly_t (next in linked list)
+    public IntPtr chain;    // Pointer to glpoly_t (start of linked list)
+    public int numVerts;
+    
+    // No need to include this field in the struct, as we calculate its offset and marshal the data manually
+    //[MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)] public QGLPolyVert[] verts;    // Variable sized
+}
+
+[StructLayout(LayoutKind.Sequential, Pack = 0)]
+public struct QGLPolyVert
+{
+    public QVec3 position;
+    public QVec2 textureUV;
+    public QVec2 lightmapUV;
 }

Assets/Scripts/Modules/BrushModel.cs

@@ -0,0 +1,81 @@
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.Rendering;
+
+public class BrushModel
+{
+    private readonly string name;
+    private readonly List<Mesh> meshes = new List<Mesh>();
+
+    public BrushModel(string name)
+    {
+        this.name = name;
+    }
+
+    public void ImportMeshData(QModel model, QSurface[] surfaces)
+    {
+        List<Vector3> vertices = new List<Vector3>();
+        List<Vector2> textureUVs = new List<Vector2>();
+        List<Vector2> lightmapUVs = new List<Vector2>();
+        List<ushort> indices = new List<ushort>();
+        
+        for (int surfIdx = 0; surfIdx < surfaces.Length; ++surfIdx)
+        {
+            foreach (var polyVerts in surfaces[surfIdx].GetPolygons())
+            {
+                vertices.Clear();
+                textureUVs.Clear();
+                lightmapUVs.Clear();
+                indices.Clear();
+
+                for (int vertIdx = 0; vertIdx < polyVerts.Length; ++vertIdx)
+                {
+                    vertices.Add(polyVerts[vertIdx].position.ToVector3());
+                    textureUVs.Add(polyVerts[vertIdx].textureUV.ToVector2());
+                    lightmapUVs.Add(polyVerts[vertIdx].lightmapUV.ToVector2());
+                }
+
+                // Reconstruct triangle fan (in reverse order)
+                for (ushort index = 2; index < polyVerts.Length; ++index)
+                {
+                    indices.Add(index);
+                    indices.Add((ushort)(index - 1));
+                    indices.Add(0);
+                }
+                
+                Mesh mesh = new Mesh();
+                mesh.SetVertices(vertices);
+                mesh.SetUVs(0, textureUVs);
+                mesh.SetUVs(1, lightmapUVs);
+                mesh.SetIndices(indices, MeshTopology.Triangles, 0);
+                mesh.RecalculateNormals();
+                mesh.UploadMeshData(true);
+                meshes.Add(mesh);
+            }
+        }
+        
+        // DEBUG
+        var go = new GameObject(name);
+        var mat = new Material(Shader.Find("Universal Render Pipeline/Simple Lit"));
+        
+        for (int i = 0; i < meshes.Count; ++i)
+        {
+            var mesh = meshes[i];
+
+            var meshGO = new GameObject($"Surface_{i}");
+            meshGO.transform.SetParent(go.transform);
+            
+            var mf = meshGO.AddComponent<MeshFilter>();
+            mf.sharedMesh = mesh;
+            
+            var mr = meshGO.AddComponent<MeshRenderer>();
+            mr.sharedMaterial = mat;
+            mr.shadowCastingMode = ShadowCastingMode.Off;
+            mr.receiveShadows = false;
+            mr.lightProbeUsage = LightProbeUsage.Off;
+            mr.reflectionProbeUsage = ReflectionProbeUsage.Off;
+        }
+        
+        go.transform.SetPositionAndRotation(Vector3.zero, Quaternion.Euler(-90, 90, 0));
+    }
+}

Assets/Scripts/Modules/BrushModel.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 20d063dc6801478691510afa943bc87e
+timeCreated: 1619358727

Assets/Scripts/Modules/RenderModule.Interop.cs

@@ -92,12 +92,9 @@ public partial class RenderModule: CallbackHandler<RenderModule>
         if (model == null || model.type != QModelType.Brush)
             return -1;
 
-        var vertices = model.vertices.ToStructArray<QVec3>(model.numVertices);
-        var edges = model.edges.ToStructArray<QEdge>(model.numEdges);
         var surfaces = model.surfaces.ToStructArray<QSurface>(model.numSurfaces);
-        var surfaceEdges = model.surfEdges.ToIntArray(model.numSurfEdges);
-        
-        return GetSelf(target).UploadBrushModel(model, vertices, edges, surfaces, surfaceEdges);
+
+        return GetSelf(target).UploadBrushModel(model, surfaces);
     }
 
     [UnmanagedFunctionPointer(CallingConvention.Cdecl)]

Assets/Scripts/Modules/RenderModule.cs

@@ -119,12 +119,12 @@ public partial class RenderModule
         return 1;
     }
     
-    private int UploadBrushModel(QModel model, QVec3[] vertices, QEdge[] edges, QSurface[] surfaces, int[] surfaceEdges)
+    private int UploadBrushModel(QModel model, QSurface[] surfaces)
     {
         Debug.Log($"Brush model '{model.name}' with {model.numVertices} vertices, {model.numEdges} edges, {model.numSurfaces} surfaces");
 
         var brushModel = new BrushModel(model.name);
-        brushModel.ImportMeshData(model, vertices, edges, surfaces, surfaceEdges);
+        brushModel.ImportMeshData(model, surfaces);
         
         return 1;
     }