1 files changed, 74 insertions, 0 deletions
diff --git a/thirdparty/meshoptimizer/vfetchoptimizer.cpp b/thirdparty/meshoptimizer/vfetchoptimizer.cpp
new file mode 100644
index 0000000000..465d6df5ca
--- /dev/null
+++ b/thirdparty/meshoptimizer/vfetchoptimizer.cpp
@@ -0,0 +1,74 @@
+// This file is part of meshoptimizer library; see meshoptimizer.h for version/license details
+#include "meshoptimizer.h"
+
+#include <assert.h>
+#include <string.h>
+
+size_t meshopt_optimizeVertexFetchRemap(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count)
+{
+	assert(index_count % 3 == 0);
+
+	memset(destination, -1, vertex_count * sizeof(unsigned int));
+
+	unsigned int next_vertex = 0;
+
+	for (size_t i = 0; i < index_count; ++i)
+	{
+		unsigned int index = indices[i];
+		assert(index < vertex_count);
+
+		if (destination[index] == ~0u)
+		{
+			destination[index] = next_vertex++;
+		}
+	}
+
+	assert(next_vertex <= vertex_count);
+
+	return next_vertex;
+}
+
+size_t meshopt_optimizeVertexFetch(void* destination, unsigned int* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size)
+{
+	assert(index_count % 3 == 0);
+	assert(vertex_size > 0 && vertex_size <= 256);
+
+	meshopt_Allocator allocator;
+
+	// support in-place optimization
+	if (destination == vertices)
+	{
+		unsigned char* vertices_copy = allocator.allocate<unsigned char>(vertex_count * vertex_size);
+		memcpy(vertices_copy, vertices, vertex_count * vertex_size);
+		vertices = vertices_copy;
+	}
+
+	// build vertex remap table
+	unsigned int* vertex_remap = allocator.allocate<unsigned int>(vertex_count);
+	memset(vertex_remap, -1, vertex_count * sizeof(unsigned int));
+
+	unsigned int next_vertex = 0;
+
+	for (size_t i = 0; i < index_count; ++i)
+	{
+		unsigned int index = indices[i];
+		assert(index < vertex_count);
+
+		unsigned int& remap = vertex_remap[index];
+
+		if (remap == ~0u) // vertex was not added to destination VB
+		{
+			// add vertex
+			memcpy(static_cast<unsigned char*>(destination) + next_vertex * vertex_size, static_cast<const unsigned char*>(vertices) + index * vertex_size, vertex_size);
+
+			remap = next_vertex++;
+		}
+
+		// modify indices in place
+		indices[i] = remap;
+	}
+
+	assert(next_vertex <= vertex_count);
+
+	return next_vertex;
+}