Merge pull request #1042 from zeux/optrot

meshletutils: Tweak optimizeMeshletLevel rotation for compressibility

Author: zeux

src/meshletutils.cpp

@@ -491,7 +491,7 @@ void meshopt_optimizeMeshletLevel(unsigned int* meshlet_vertices, size_t vertex_
 				// if subsequent triangles don't share edges ca or bc, we can rotate the triangle to fix this
 				bool needab = false, needbc = false, needca = false;
 
-				for (size_t j = i + 1; j < triangle_count && j <= i + 3; ++j)
+				for (size_t j = i + 1; j < triangle_count && j <= i + cache_cutoff; ++j)
 				{
 					unsigned char oa = indices[j * 3 + 0], ob = indices[j * 3 + 1], oc = indices[j * 3 + 2];
 
@@ -513,6 +513,12 @@ void meshopt_optimizeMeshletLevel(unsigned int* meshlet_vertices, size_t vertex_
 					unsigned char t = c;
 					c = b, b = a, a = t;
 				}
+				else if (!needab && needbc && !needca)
+				{
+					// abc -> cab: put bc at most recent FIFO position
+					unsigned char t = c;
+					c = b, b = a, a = t;
+				}
 			}
 
 			indices[i * 3 + 0] = a, indices[i * 3 + 1] = b, indices[i * 3 + 2] = c;