Remove the old CSG path and the BurstTriangulator dependency (#58)

The exact CSG has been the default for a while; the float CSG that made polygon
loops was only reachable through an internal switch.

- Removed the loop CSG (PerformCSGJob, the intersection loop, merge and loop
  vertex cache jobs), the loop triangulation and repair in
  GenerateSurfaceTrianglesJob, the kExactCSG switch, the propagation rounds,
  interned planes and the float brush intersection test.
- GenerateSurfaceTrianglesJob is Burst compiled itself.
- BurstTriangulator was only used by the loop triangulation: the submodule
  and its reference are gone.
- Tests that compared the two paths, or only covered the old one, are gone;
  the concrete pad area checks now run.

Fixes #57

Author: LogicalError

.gitmodules

@@ -1,6 +1,3 @@
 [submodule "Dependencies/CustomAssetMetadata"]
 	path = Dependencies/CustomAssetMetadata
 	url = https://github.com/LogicalError/CustomAssetMetadata.git
-[submodule "Dependencies/BurstTriangulator"]
-	path = Dependencies/BurstTriangulator
-	url = https://github.com/RadicalCSG/BurstTriangulator.git

CONTRIBUTING.md

@@ -24,7 +24,7 @@ Chisel is a Unity package. To work on it, put it in a Unity project as an embedd
    `git submodule update --init` in it.
 3. Open the project in Unity. The first time takes a while, because Burst compiles a lot of code.
 
-The package's dependencies, BurstTriangulator and CustomAssetMetadata, are git submodules in `Dependencies`.
+The package's dependency, CustomAssetMetadata, is a git submodule in `Dependencies`.
 
 ## Where things are
 

Components/Managers/ChiselModelManager.cs

@@ -848,9 +848,8 @@ public static Hash128 GetComponentInputHash(ChiselModelComponent model)
 
 		/// <summary>
 		/// What both hashes have to cover and neither can see in the model: the version of the code that builds the
-		/// meshes, which of its two CSG algorithms builds them, and the helper materials <c>FinishMeshUpdates</c> hands
-		/// out, which no surface names. Without the code version a saved scene would keep meshes built by code that has
-		/// since changed, and without the algorithm meshes built by the other one.
+		/// meshes, and the helper materials <c>FinishMeshUpdates</c> hands out, which no surface names. Without the code
+		/// version a saved scene would keep meshes built by code that has since changed.
 		/// </summary>
 		static void AppendEnvironment(ref Hash128 hash)
 		{
@@ -861,9 +860,6 @@ static void AppendEnvironment(ref Hash128 hash)
 			}
 			hash.Append(ref s_CodeVersion);
 
-			int algorithm = CompactHierarchyManager.TreeUpdate.kExactCSG ? 1 : 0;
-			hash.Append(ref algorithm);
-
 			AppendMaterialIdentity(ref hash, ChiselProjectSettings.ForceShadowOnlySurfacesMaterial);
 			AppendMaterialIdentity(ref hash, ChiselProjectSettings.CollisionSurfacesMaterial);
 			var debugVisualizationMaterials = ChiselProjectSettings.DebugVisualizationMaterials;

Core/2.Processing/CSGMath.cs

@@ -42,8 +42,8 @@ public static float3 EdgePlaneCrossing(float3 v0, float3 v1, float d0, float d1)
         public static double3 PlaneIntersection(double4 plane0, double4 plane1, double4 plane2)
             => PlaneExtensions.Intersection(plane0, plane1, plane2);
 
-        // One vertex-pair term of Newell's polygon-normal accumulation, in double. Matches
-        // CalculatePlaneNormal in PerformCSGJob. Accumulate over consecutive (prev,curr) verts, normalize.
+        // One vertex-pair term of Newell's polygon-normal accumulation, in double. Accumulate over consecutive
+        // (prev,curr) verts, normalize.
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static float3 NewellTerm(float3 prev, float3 curr)
         {

Core/2.Processing/Cache/ChiselLookup.cs

@@ -26,9 +26,8 @@ public class Data
             public NativeList<MinMaxAABB>                                       brushTreeSpaceBoundCache;
             public NativeList<BlobAssetReference<BrushTreeSpacePlanes>>         brushTreeSpacePlaneCache;
             public NativeList<BlobAssetReference<BrushesTouchedByBrush>>        brushesTouchedByBrushCache;
-            public NativeList<UnsafeList<float3>>                               loopVerticesCache;
             // Each brush as the exact CSG sees it (ExactBrush: exact planes, corners, bounds), rebuilt when the brush
-            // changes (ExactInputJob). Only kept up to date while the tree is built exactly (builtExact).
+            // changes (ExactInputJob).
             public NativeList<BlobAssetReference<ExactBrush>>                   exactBrushCache;
 
             public NativeList<ChiselDecalInstance>                              decalInstances;
@@ -44,9 +43,6 @@ public class Data
 
             public NativeParallelHashMap<CompactNodeID, BlobAssetReference<ChiselBrushRenderBuffer>> brushRenderBufferLookup;
 
-            // Whether the tree's output was last built by the exact CSG (TreeUpdate.kExactCSG). An update by the other
-            // algorithm rebuilds every brush of the tree, so the two never mix in one tree's output.
-            public bool                                                         builtExact;
             // What each hotspot layout was at the last update (ChiselHotspotStore.LayoutHashes, by id - 1)
             public NativeList<uint>                                             hotspotLayoutHashes;
             // Where the weld's last step moved the corners it moved at the last update (from, to; OutputModelWeld)
@@ -79,7 +75,6 @@ internal void Initialize()
 				brushTreeSpacePlaneCache    = new NativeList<BlobAssetReference<BrushTreeSpacePlanes>>(1000, Allocator.Persistent); // Confirmed to get disposed
 				brushesTouchedByBrushCache  = new NativeList<BlobAssetReference<BrushesTouchedByBrush>>(1000, Allocator.Persistent); // Confirmed to get disposed
 				brushRenderBufferCache      = new NativeList<BlobAssetReference<ChiselBrushRenderBuffer>>(1000, Allocator.Persistent); // Confirmed to get disposed
-				loopVerticesCache           = new NativeList<UnsafeList<float3>>(1000, Allocator.Persistent); // Confirmed to get disposed
 				exactBrushCache             = new NativeList<BlobAssetReference<ExactBrush>>(1000, Allocator.Persistent);
 
 				decalInstances              = new NativeList<ChiselDecalInstance>(16, Allocator.Persistent);
@@ -132,9 +127,6 @@ internal void EnsureCapacity(int brushCount)
                 if (brushRenderBufferCache.Capacity < brushCount)
                     brushRenderBufferCache.Capacity = brushCount;
 
-                if (loopVerticesCache.Capacity < brushCount)
-                    loopVerticesCache.Capacity = brushCount;
-
                 if (exactBrushCache.Capacity < brushCount)
                     exactBrushCache.Capacity = brushCount;
             }
@@ -235,18 +227,6 @@ internal void Dispose()
                     brushRenderBufferCache.Dispose();
                 }
                 brushRenderBufferCache = default;
-                if (loopVerticesCache.IsCreated)
-                {
-                    for (int i = 0; i < loopVerticesCache.Length; i++)
-                    {
-                        if (loopVerticesCache[i].IsCreated)
-                            loopVerticesCache[i].Dispose();
-                        loopVerticesCache[i] = default;
-                    }
-                    loopVerticesCache.Clear();
-                    loopVerticesCache.Dispose();
-                }
-                loopVerticesCache = default;
                 if (exactBrushCache.IsCreated)
                 {
                     for (int i = 0; i < exactBrushCache.Length; i++)
@@ -307,7 +287,6 @@ internal void Dispose()
                 if (brushRenderBufferLookup.IsCreated)
                     brushRenderBufferLookup.Dispose();
                 brushRenderBufferLookup = default;
-                builtExact = false;
             }
         }
 

Core/2.Processing/Containers/InternedPlanes.cs

@@ -723,7 +723,7 @@ int Route(ref ExactList<byte> inside, ref ExactList<ushort> routingRows, ref Exa
                 int row = lookupStart[k] + input;
                 if (row < lookupStart[k] || row >= lookupEnd[k])
                 {
-                    // the same as PerformCSGJob: a lookup without a row for this input leaves the input as it is
+                    // a lookup without a row for this input leaves the input as it is
                     routingErrors++;
                     continue;
                 }