Mathias Agopian
ffa2886493
- Fix potential division by zero in decodeMeshoptCompression when stride is 0. - Fix ignored errors in release builds for meshopt decoding by returning bool and checking the result in ResourceLoader.cpp. - Fix potential integer underflow in computeBindingSize when count is 0 by returning 0. - Update ResourceLoader.cpp to skip buffer upload when computeBindingSize returns 0, preventing potential OOM or OOB reads.
290 lines
11 KiB
C++
290 lines
11 KiB
C++
/*
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* Copyright (C) 2024 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "Utility.h"
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#include "DracoCache.h"
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#include "FFilamentAsset.h"
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#include "GltfEnums.h"
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#include <private/utils/Tracing.h>
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#include <utils/Log.h>
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#include <utils/Panic.h>
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#define CGLTF_IMPLEMENTATION
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#include <cgltf.h>
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#include <meshoptimizer.h>
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#include <limits>
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namespace filament::gltfio::utility {
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using namespace utils;
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void decodeDracoMeshes(cgltf_data const* gltf, cgltf_primitive const* prim,
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DracoCache* dracoCache) {
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if (!prim->has_draco_mesh_compression) {
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return;
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}
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// For a given primitive and attribute, find the corresponding accessor.
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auto findAccessor = [](const cgltf_primitive* prim, cgltf_attribute_type type, cgltf_int idx) {
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for (cgltf_size i = 0; i < prim->attributes_count; i++) {
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const cgltf_attribute& attr = prim->attributes[i];
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if (attr.type == type && attr.index == idx) {
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return attr.data;
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}
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}
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return (cgltf_accessor*) nullptr;
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};
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const cgltf_draco_mesh_compression& draco = prim->draco_mesh_compression;
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// Check if we have already decoded this mesh.
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DracoMesh* mesh = dracoCache->findOrCreateMesh(draco.buffer_view);
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if (!mesh) {
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slog.e << "Cannot decompress mesh, Draco decoding error." << io::endl;
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return;
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}
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// Copy over the decompressed data, converting the data type if necessary.
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if (prim->indices && !mesh->getFaceIndices(prim->indices)) {
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return;
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}
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// Go through each attribute in the decompressed mesh.
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for (cgltf_size i = 0; i < draco.attributes_count; i++) {
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// In cgltf, each Draco attribute's data pointer is an attribute id, not an accessor.
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const uint32_t id = draco.attributes[i].data - gltf->accessors;
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// Find the destination accessor; this contains the desired component type, etc.
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const cgltf_attribute_type type = draco.attributes[i].type;
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const cgltf_int index = draco.attributes[i].index;
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cgltf_accessor* accessor = findAccessor(prim, type, index);
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if (!accessor) {
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slog.w << "Cannot find matching accessor for Draco id " << id << io::endl;
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continue;
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}
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// Copy over the decompressed data, converting the data type if necessary.
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if (!mesh->getVertexAttributes(id, accessor)) {
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break;
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}
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}
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}
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bool decodeMeshoptCompression(cgltf_data* data) {
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for (size_t i = 0; i < data->buffer_views_count; ++i) {
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if (!data->buffer_views[i].has_meshopt_compression) {
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continue;
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}
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cgltf_meshopt_compression* compression = &data->buffer_views[i].meshopt_compression;
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const uint8_t* source = (const uint8_t*) compression->buffer->data;
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assert_invariant(source);
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source += compression->offset;
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if (compression->stride == 0) {
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slog.e << "gltfio: meshopt decompression failed, stride is 0." << io::endl;
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return false;
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}
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size_t const theoreticalMaxCount = std::numeric_limits<size_t>::max() / compression->stride;
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FILAMENT_CHECK_PRECONDITION(compression->count <= theoreticalMaxCount)
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<< "gltfio: meshopt decompression exceeds maximum count of " << theoreticalMaxCount
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<< " (actual=" << compression->count << ") given stride of " << compression->stride
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<< ".";
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// This memory is freed by cgltf.
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void* destination = malloc(compression->count * compression->stride);
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assert_invariant(destination);
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int error = 0;
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switch (compression->mode) {
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case cgltf_meshopt_compression_mode_invalid:
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break;
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case cgltf_meshopt_compression_mode_attributes:
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error = meshopt_decodeVertexBuffer(destination, compression->count,
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compression->stride, source, compression->size);
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break;
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case cgltf_meshopt_compression_mode_triangles:
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error = meshopt_decodeIndexBuffer(destination, compression->count,
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compression->stride, source, compression->size);
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break;
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case cgltf_meshopt_compression_mode_indices:
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error = meshopt_decodeIndexSequence(destination, compression->count,
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compression->stride, source, compression->size);
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break;
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default:
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assert_invariant(false);
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break;
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}
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if (error != 0) {
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slog.e << "gltfio: meshopt decompression failed with error " << error << io::endl;
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free(destination);
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return false;
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}
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switch (compression->filter) {
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case cgltf_meshopt_compression_filter_none:
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break;
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case cgltf_meshopt_compression_filter_octahedral:
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meshopt_decodeFilterOct(destination, compression->count, compression->stride);
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break;
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case cgltf_meshopt_compression_filter_quaternion:
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meshopt_decodeFilterQuat(destination, compression->count, compression->stride);
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break;
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case cgltf_meshopt_compression_filter_exponential:
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meshopt_decodeFilterExp(destination, compression->count, compression->stride);
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break;
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default:
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assert_invariant(false);
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break;
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}
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data->buffer_views[i].data = destination;
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}
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return true;
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}
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bool primitiveHasVertexColor(cgltf_primitive* inPrim) {
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for (int slot = 0; slot < inPrim->attributes_count; slot++) {
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const cgltf_attribute& inputAttribute = inPrim->attributes[slot];
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if (inputAttribute.type == cgltf_attribute_type_color) {
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return true;
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}
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}
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return false;
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}
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// Sometimes a glTF bufferview includes unused data at the end (e.g. in skinning.gltf) so we need to
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// compute the correct size of the vertex buffer. Filament automatically infers the size of
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// driver-level vertex buffers from the attribute data (stride, count, offset) and clients are
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// expected to avoid uploading data blobs that exceed this size. Since this information doesn't
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// exist in the glTF we need to compute it manually. This is a bit of a cheat, cgltf_calc_size is
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// private but its implementation file is available in this cpp file.
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uint32_t computeBindingSize(cgltf_accessor const* accessor) {
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if (accessor->count == 0) {
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return 0;
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}
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cgltf_size element_size = cgltf_calc_size(accessor->type, accessor->component_type);
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return uint32_t(accessor->stride * (accessor->count - 1) + element_size);
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}
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void convertBytesToShorts(uint16_t* dst, uint8_t const* src, size_t count) {
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for (size_t i = 0; i < count; ++i) {
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dst[i] = src[i];
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}
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}
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uint32_t computeBindingOffset(cgltf_accessor const* accessor) {
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return uint32_t(accessor->offset + accessor->buffer_view->offset);
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}
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bool requiresConversion(cgltf_accessor const* accessor) {
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if (UTILS_UNLIKELY(accessor->is_sparse)) {
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return true;
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}
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const cgltf_type type = accessor->type;
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const cgltf_component_type ctype = accessor->component_type;
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filament::VertexBuffer::AttributeType permitted;
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filament::VertexBuffer::AttributeType actual;
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UTILS_UNUSED_IN_RELEASE bool supported = getElementType(type, ctype, &permitted, &actual);
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assert_invariant(supported && "Unsupported types");
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return permitted != actual;
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}
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bool requiresPacking(cgltf_accessor const* accessor) {
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if (requiresConversion(accessor)) {
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return true;
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}
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const size_t dim = cgltf_num_components(accessor->type);
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switch (accessor->component_type) {
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case cgltf_component_type_r_8:
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case cgltf_component_type_r_8u:
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return accessor->stride != dim;
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case cgltf_component_type_r_16:
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case cgltf_component_type_r_16u:
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return accessor->stride != dim * 2;
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case cgltf_component_type_r_32u:
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case cgltf_component_type_r_32f:
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return accessor->stride != dim * 4;
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default:
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assert_invariant(false);
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return true;
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}
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}
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bool loadCgltfBuffers(cgltf_data const* gltf, char const* gltfPath,
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UriDataCacheHandle uriDataCacheHandle) {
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FILAMENT_TRACING_CONTEXT(FILAMENT_TRACING_CATEGORY_GLTFIO);
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FILAMENT_TRACING_NAME_BEGIN(FILAMENT_TRACING_CATEGORY_GLTFIO, "Load buffers");
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cgltf_options options{};
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// For emscripten and Android builds we supply a custom file reader callback that looks inside a
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// cache of externally-supplied data blobs, rather than loading from the filesystem.
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#if !GLTFIO_USE_FILESYSTEM
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struct Closure {
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UriDataCacheHandle uriDataCache;
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const cgltf_data* gltf;
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};
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Closure closure = { uriDataCacheHandle, gltf };
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options.file.user_data = &closure;
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options.file.read = [](const cgltf_memory_options* memoryOpts,
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const cgltf_file_options* fileOpts, const char* path,
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cgltf_size* size, void** data) {
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Closure* closure = (Closure*) fileOpts->user_data;
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auto& uriDataCache = closure->uriDataCache;
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if (auto iter = uriDataCache->find(path); iter != uriDataCache->end()) {
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*size = iter->second.size;
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*data = iter->second.buffer;
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} else {
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// Even if we don't find the given resource in the cache, we still return a successful
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// error code, because we allow downloads to finish after the decoding work starts.
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*size = 0;
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*data = 0;
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}
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return cgltf_result_success;
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};
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#endif
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// Read data from the file system and base64 URIs.
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cgltf_result result = cgltf_load_buffers(&options, (cgltf_data*) gltf, gltfPath);
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if (result != cgltf_result_success) {
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slog.e << "Unable to load resources." << io::endl;
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return false;
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}
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FILAMENT_TRACING_NAME_END(FILAMENT_TRACING_CATEGORY_GLTFIO);
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#ifndef NDEBUG
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if (cgltf_validate((cgltf_data*) gltf) != cgltf_result_success) {
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slog.e << "Failed cgltf validation." << io::endl;
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return false;
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}
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#endif
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return true;
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}
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} // namespace filament::gltfio::utility
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