Merge pull request #842 from zeux/versions

vertex/indexcodec: Add meshopt_decodeVertex/IndexVersion

Author: zeux

demo/tests.cpp

@@ -616,6 +616,25 @@ static void encodeVertexEmpty()
 	assert(meshopt_decodeVertexBuffer(NULL, 0, 16, &buffer[0], buffer.size()) == 0);
 }
 
+static void decodeVersion()
+{
+	assert(meshopt_decodeVertexVersion(reinterpret_cast<const unsigned char*>("\xa0"), 1) == 0);
+	assert(meshopt_decodeVertexVersion(reinterpret_cast<const unsigned char*>("\xa1"), 1) == 1);
+	assert(meshopt_decodeVertexVersion(reinterpret_cast<const unsigned char*>("\xa1hello"), 6) == 1);
+
+	assert(meshopt_decodeVertexVersion(NULL, 0) == -1);
+	assert(meshopt_decodeVertexVersion(reinterpret_cast<const unsigned char*>("\xa7"), 1) == -1);
+	assert(meshopt_decodeVertexVersion(reinterpret_cast<const unsigned char*>("\xb1"), 1) == -1);
+
+	assert(meshopt_decodeIndexVersion(reinterpret_cast<const unsigned char*>("\xe0"), 1) == 0);
+	assert(meshopt_decodeIndexVersion(reinterpret_cast<const unsigned char*>("\xd1"), 1) == 1);
+	assert(meshopt_decodeIndexVersion(reinterpret_cast<const unsigned char*>("\xe1hello"), 6) == 1);
+
+	assert(meshopt_decodeIndexVersion(NULL, 0) == -1);
+	assert(meshopt_decodeIndexVersion(reinterpret_cast<const unsigned char*>("\xa7"), 1) == -1);
+	assert(meshopt_decodeIndexVersion(reinterpret_cast<const unsigned char*>("\xa1"), 1) == -1);
+}
+
 static void decodeFilterOct8()
 {
 	const unsigned char data[4 * 4] = {
@@ -2151,6 +2170,8 @@ void runTests()
 		encodeVertexMemorySafe();
 	}
 
+	decodeVersion();
+
 	decodeFilterOct8();
 	decodeFilterOct12();
 	decodeFilterQuat12();

gltf/parsegltf.cpp

@@ -518,6 +518,8 @@ static bool freeUnusedBuffers(cgltf_data* data)
 
 static cgltf_result decompressMeshopt(cgltf_data* data)
 {
+	bool warned = false;
+
 	for (size_t i = 0; i < data->buffer_views_count; ++i)
 	{
 		if (!data->buffer_views[i].has_meshopt_compression)
@@ -536,18 +538,22 @@ static cgltf_result decompressMeshopt(cgltf_data* data)
 		data->buffer_views[i].data = result;
 
 		int rc = -1;
+		bool warn = false;
 
 		switch (mc->mode)
 		{
 		case cgltf_meshopt_compression_mode_attributes:
+			warn = meshopt_decodeVertexVersion(source, mc->size) != 0;
 			rc = meshopt_decodeVertexBuffer(result, mc->count, mc->stride, source, mc->size);
 			break;
 
 		case cgltf_meshopt_compression_mode_triangles:
+			warn = meshopt_decodeIndexVersion(source, mc->size) != 1;
 			rc = meshopt_decodeIndexBuffer(result, mc->count, mc->stride, source, mc->size);
 			break;
 
 		case cgltf_meshopt_compression_mode_indices:
+			warn = meshopt_decodeIndexVersion(source, mc->size) != 1;
 			rc = meshopt_decodeIndexSequence(result, mc->count, mc->stride, source, mc->size);
 			break;
 
@@ -558,6 +564,12 @@ static cgltf_result decompressMeshopt(cgltf_data* data)
 		if (rc != 0)
 			return cgltf_result_io_error;
 
+		if (warn && !warned)
+		{
+			fprintf(stderr, "Warning: EXT_meshopt_compression data uses versions outside of the glTF specification (vertex 0 / index 1 expected)\n");
+			warned = true;
+		}
+
 		switch (mc->filter)
 		{
 		case cgltf_meshopt_compression_filter_octahedral:

src/indexcodec.cpp

@@ -14,6 +14,7 @@ const unsigned char kIndexHeader = 0xe0;
 const unsigned char kSequenceHeader = 0xd0;
 
 static int gEncodeIndexVersion = 1;
+const int kDecodeIndexVersion = 1;
 
 typedef unsigned int VertexFifo[16];
 typedef unsigned int EdgeFifo[16][2];
@@ -354,11 +355,28 @@ size_t meshopt_encodeIndexBufferBound(size_t index_count, size_t vertex_count)
 
 void meshopt_encodeIndexVersion(int version)
 {
-	assert(unsigned(version) <= 1);
+	assert(unsigned(version) <= unsigned(meshopt::kDecodeIndexVersion));
 
 	meshopt::gEncodeIndexVersion = version;
 }
 
+int meshopt_decodeIndexVersion(const unsigned char* buffer, size_t buffer_size)
+{
+	if (buffer_size < 1)
+		return -1;
+
+	unsigned char header = buffer[0];
+
+	if ((header & 0xf0) != meshopt::kIndexHeader && (header & 0xf0) != meshopt::kSequenceHeader)
+		return -1;
+
+	int version = header & 0x0f;
+	if (version > meshopt::kDecodeIndexVersion)
+		return -1;
+
+	return version;
+}
+
 int meshopt_decodeIndexBuffer(void* destination, size_t index_count, size_t index_size, const unsigned char* buffer, size_t buffer_size)
 {
 	using namespace meshopt;
@@ -374,7 +392,7 @@ int meshopt_decodeIndexBuffer(void* destination, size_t index_count, size_t inde
 		return -1;
 
 	int version = buffer[0] & 0x0f;
-	if (version > 1)
+	if (version > kDecodeIndexVersion)
 		return -1;
 
 	EdgeFifo edgefifo;
@@ -627,7 +645,7 @@ int meshopt_decodeIndexSequence(void* destination, size_t index_count, size_t in
 		return -1;
 
 	int version = buffer[0] & 0x0f;
-	if (version > 1)
+	if (version > kDecodeIndexVersion)
 		return -1;
 
 	const unsigned char* data = buffer + 1;

src/meshoptimizer.h

@@ -243,6 +243,13 @@ MESHOPTIMIZER_API void meshopt_encodeIndexVersion(int version);
  */
 MESHOPTIMIZER_API int meshopt_decodeIndexBuffer(void* destination, size_t index_count, size_t index_size, const unsigned char* buffer, size_t buffer_size);
 
+/**
+ * Get encoded index format version
+ * Returns format version of the encoded index buffer/sequence, or -1 if the buffer header is invalid
+ * Note that a non-negative value doesn't guarantee that the buffer will be decoded correctly if the input is malformed.
+ */
+MESHOPTIMIZER_API int meshopt_decodeIndexVersion(const unsigned char* buffer, size_t buffer_size);
+
 /**
  * Index sequence encoder
  * Encodes index sequence into an array of bytes that is generally smaller and compresses better compared to original.
@@ -303,6 +310,13 @@ MESHOPTIMIZER_API void meshopt_encodeVertexVersion(int version);
  */
 MESHOPTIMIZER_API int meshopt_decodeVertexBuffer(void* destination, size_t vertex_count, size_t vertex_size, const unsigned char* buffer, size_t buffer_size);
 
+/**
+ * Get encoded vertex format version
+ * Returns format version of the encoded vertex buffer, or -1 if the buffer header is invalid
+ * Note that a non-negative value doesn't guarantee that the buffer will be decoded correctly if the input is malformed.
+ */
+MESHOPTIMIZER_API int meshopt_decodeVertexVersion(const unsigned char* buffer, size_t buffer_size);
+
 /**
  * Vertex buffer filters
  * These functions can be used to filter output of meshopt_decodeVertexBuffer in-place.

src/vertexcodec.cpp

@@ -123,6 +123,7 @@ namespace meshopt
 const unsigned char kVertexHeader = 0xa0;
 
 static int gEncodeVertexVersion = 0;
+const int kDecodeVertexVersion = 1;
 
 const size_t kVertexBlockSizeBytes = 8192;
 const size_t kVertexBlockMaxSize = 256;
@@ -1803,11 +1804,28 @@ size_t meshopt_encodeVertexBufferBound(size_t vertex_count, size_t vertex_size)
 
 void meshopt_encodeVertexVersion(int version)
 {
-	assert(unsigned(version) <= 1);
+	assert(unsigned(version) <= unsigned(meshopt::kDecodeVertexVersion));
 
 	meshopt::gEncodeVertexVersion = version;
 }
 
+int meshopt_decodeVertexVersion(const unsigned char* buffer, size_t buffer_size)
+{
+	if (buffer_size < 1)
+		return -1;
+
+	unsigned char header = buffer[0];
+
+	if ((header & 0xf0) != meshopt::kVertexHeader)
+		return -1;
+
+	int version = header & 0x0f;
+	if (version > meshopt::kDecodeVertexVersion)
+		return -1;
+
+	return version;
+}
+
 int meshopt_decodeVertexBuffer(void* destination, size_t vertex_count, size_t vertex_size, const unsigned char* buffer, size_t buffer_size)
 {
 	using namespace meshopt;
@@ -1844,7 +1862,7 @@ int meshopt_decodeVertexBuffer(void* destination, size_t vertex_count, size_t ve
 		return -1;
 
 	int version = data_header & 0x0f;
-	if (version > 1)
+	if (version > kDecodeVertexVersion)
 		return -1;
 
 	size_t tail_size = vertex_size + (version == 0 ? 0 : vertex_size / 4);