tools: Add fuzzing driver for clusterization

We use a similar basic mesh construction from simplifyfuzz and test
both clusterizers with various vertex/triangle limits.

Author: zeux

Makefile

@@ -228,6 +228,9 @@ codectest: tools/codectest.cpp $(LIBRARY)
 codecfuzz: tools/codecfuzz.cpp src/vertexcodec.cpp src/indexcodec.cpp
 	$(CXX) $^ -fsanitize=fuzzer,address,undefined -O1 -g -o $@
 
+clusterfuzz: tools/clusterfuzz.cpp src/clusterizer.cpp
+	$(CXX) $^ -fsanitize=fuzzer,address,undefined -O1 -g -o $@
+
 simplifyfuzz: tools/simplifyfuzz.cpp src/simplifier.cpp
 	$(CXX) $^ -fsanitize=fuzzer,address,undefined -O1 -g -o $@
 

tools/clusterfuzz.cpp

@@ -0,0 +1,52 @@
+#include "../src/meshoptimizer.h"
+
+#include <float.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* buffer, size_t size)
+{
+	if (size == 0)
+		return 0;
+
+	srand(buffer[0]);
+
+	float vb[100][4];
+
+	for (int i = 0; i < 100; ++i)
+	{
+		vb[i][0] = rand() % 10;
+		vb[i][1] = rand() % 10;
+		vb[i][2] = rand() % 10;
+		vb[i][3] = rand() % 10;
+	}
+
+	unsigned int ib[999];
+	int indices = (size - 1) < 999 ? (size - 1) / 3 * 3 : 999;
+
+	for (int i = 0; i < indices; ++i)
+		ib[i] = buffer[1 + i] % 100;
+
+	meshopt_Meshlet ml[333];
+	unsigned int mv[333 * 3];
+	unsigned char mt[333 * 4];
+
+	meshopt_buildMeshlets(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 4, /* max_triangles= */ 4, 0.f);
+
+	meshopt_buildMeshletsScan(ml, mv, mt, ib, indices, 100, /* max_vertices= */ 4, /* max_triangles= */ 4);
+	meshopt_buildMeshletsScan(ml, mv, mt, ib, indices, 100, /* max_vertices= */ 4, /* max_triangles= */ 8);
+
+	meshopt_buildMeshletsFlex(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 4, /* min_triangles= */ 4, /* max_triangles= */ 8, 0.f, 2.f);
+	meshopt_buildMeshletsFlex(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 8, /* min_triangles= */ 8, /* max_triangles= */ 16, 0.f, 2.f);
+	meshopt_buildMeshletsFlex(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 16, /* min_triangles= */ 8, /* max_triangles= */ 32, 0.f, 2.f);
+	meshopt_buildMeshletsFlex(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 16, /* min_triangles= */ 16, /* max_triangles= */ 32, 0.f, 2.f);
+
+	meshopt_buildMeshletsSplit(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 4, /* min_triangles= */ 4, /* max_triangles= */ 8);
+	meshopt_buildMeshletsSplit(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 8, /* min_triangles= */ 4, /* max_triangles= */ 32);
+	meshopt_buildMeshletsSplit(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 8, /* min_triangles= */ 8, /* max_triangles= */ 32);
+	meshopt_buildMeshletsSplit(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 8, /* min_triangles= */ 12, /* max_triangles= */ 32);
+	meshopt_buildMeshletsSplit(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 16, /* min_triangles= */ 16, /* max_triangles= */ 32);
+	meshopt_buildMeshletsSplit(ml, mv, mt, ib, indices, vb[0], 100, sizeof(float) * 4, /* max_vertices= */ 16, /* min_triangles= */ 32, /* max_triangles= */ 32);
+
+	return 0;
+}