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https://git.mirrors.martin98.com/https://github.com/syoyo/tinygltf.git
synced 2025-08-14 06:55:52 +08:00
Initial support for draco mesh compression. In this PR, we establish that draco is a dependency built external to tinygltf, which breaks from the current tradition of header only dependencies. For that reason, this feature is hidden behind a #define TINYGLTF_ENABLE_DRACO and requires developers to explicitly opt-in for draco support.
In this change, tinygltf any primitive using draco compression will: If indices are specified 1) Decode the index buffer using draco, creating a new buffer and bufferview, adding to Model::bufferViews and Model::buffer collections 2) Update the primitive's accessor id to reference this new decoded bufferview. For each attribute semantic specified by the draco extension 1) Decode the vertex buffer using draco, creating a new buffer and bufferview, adding to Model::bufferViews and Model::buffer collections 2) Update the primitive's accessor id to reference this new decoded bufferview.
This commit is contained in:
Alex Wood
parent
b864ea7349
commit
7319db7a50
220
tiny_gltf.h
220
tiny_gltf.h
@ -538,8 +538,9 @@ struct BufferView {
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// understood to be tightly packed
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int target; // ["ARRAY_BUFFER", "ELEMENT_ARRAY_BUFFER"]
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Value extras;
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bool dracoDecoded; // Flag indicating this has been draco decoded
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BufferView() : byteOffset(0), byteStride(0) {}
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BufferView() : byteOffset(0), byteStride(0), dracoDecoded(false) {}
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bool operator==(const BufferView &) const;
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};
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@ -658,6 +659,7 @@ struct Primitive {
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// where each target is a dict with attribues in ["POSITION, "NORMAL",
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// "TANGENT"] pointing
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// to their corresponding accessors
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ExtensionMap extensions;
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Value extras;
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Primitive() {
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@ -1060,14 +1062,19 @@ class TinyGLTF {
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#endif
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#endif
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#include "./json.hpp"
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#include "json.hpp"
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#ifdef TINYGLTF_ENABLE_DRACO
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#include "draco/core/decoder_buffer.h"
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#include "draco/compression/decode.h"
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#endif
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#ifndef TINYGLTF_NO_STB_IMAGE
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#include "./stb_image.h"
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#include "stb_image.h"
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#endif
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#ifndef TINYGLTF_NO_STB_IMAGE_WRITE
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#include "./stb_image_write.h"
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#include "stb_image_write.h"
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#endif
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#ifdef __clang__
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@ -2728,10 +2735,7 @@ static bool ParseBufferView(BufferView *bufferView, std::string *err,
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static bool ParseAccessor(Accessor *accessor, std::string *err, const json &o) {
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double bufferView = -1.0;
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if (!ParseNumberProperty(&bufferView, err, o, "bufferView", true,
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"Accessor")) {
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return false;
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}
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ParseNumberProperty(&bufferView, err, o, "bufferView", false, "Accessor");
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double byteOffset = 0.0;
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ParseNumberProperty(&byteOffset, err, o, "byteOffset", false, "Accessor");
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@ -2813,7 +2817,189 @@ static bool ParseAccessor(Accessor *accessor, std::string *err, const json &o) {
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return true;
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}
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static bool ParsePrimitive(Primitive *primitive, std::string *err,
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#ifdef TINYGLTF_ENABLE_DRACO
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static void DecodeIndexBuffer(draco::Mesh* mesh, size_t componentSize, std::vector<uint8_t>& outBuffer)
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{
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if (componentSize == 4)
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{
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assert(sizeof(mesh->face(draco::FaceIndex(0))[0]) == componentSize);
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memcpy(outBuffer.data(), &mesh->face(draco::FaceIndex(0))[0], outBuffer.size());
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}
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else
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{
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size_t faceStride = componentSize * 3;
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for (draco::FaceIndex f(0); f < mesh->num_faces(); ++f)
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{
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const draco::Mesh::Face& face = mesh->face(f);
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if (componentSize == 2)
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{
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uint16_t indices[3] = { (uint16_t)face[0].value(), (uint16_t)face[1].value(), (uint16_t)face[2].value() };
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memcpy(outBuffer.data() + f.value() * faceStride, &indices[0], faceStride);
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}
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else
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{
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uint8_t indices[3] = { (uint8_t)face[0].value(), (uint8_t)face[1].value(), (uint8_t)face[2].value() };
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memcpy(outBuffer.data() + f.value() * faceStride, &indices[0], faceStride);
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}
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}
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}
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}
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template<typename T>
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static bool GetAttributeForAllPoints(draco::Mesh* mesh, const draco::PointAttribute* pAttribute, std::vector<uint8_t>& outBuffer)
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{
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size_t byteOffset = 0;
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T values[4] = { 0, 0, 0, 0 };
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for (draco::PointIndex i(0); i < mesh->num_points(); ++i)
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{
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const draco::AttributeValueIndex val_index = pAttribute->mapped_index(i);
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if (!pAttribute->ConvertValue<T>(val_index, pAttribute->num_components(), values))
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return false;
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memcpy(outBuffer.data() + byteOffset, &values[0], sizeof(T) * pAttribute->num_components());
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byteOffset += sizeof(T) * pAttribute->num_components();
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}
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return true;
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}
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static bool GetAttributeForAllPoints(draco::Mesh* mesh, const draco::PointAttribute* pAttribute, std::vector<uint8_t>& outBuffer)
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{
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bool decodeResult = false;
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switch (pAttribute->data_type())
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{
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case draco::DT_BOOL:
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case draco::DT_UINT8:
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decodeResult = GetAttributeForAllPoints<uint8_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_INT8:
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decodeResult = GetAttributeForAllPoints<int8_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_UINT16:
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decodeResult = GetAttributeForAllPoints<uint16_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_INT16:
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decodeResult = GetAttributeForAllPoints<int16_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_INT32:
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decodeResult = GetAttributeForAllPoints<int32_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_INT64:
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decodeResult = GetAttributeForAllPoints<int64_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_UINT32:
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decodeResult = GetAttributeForAllPoints<uint32_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_UINT64:
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decodeResult = GetAttributeForAllPoints<uint64_t>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_FLOAT32:
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decodeResult = GetAttributeForAllPoints<float>(mesh, pAttribute, outBuffer);
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break;
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case draco::DT_FLOAT64:
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decodeResult = GetAttributeForAllPoints<double>(mesh, pAttribute, outBuffer);
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break;
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default:
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return false;
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}
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return decodeResult;
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}
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static bool ParseDracoExtension(Primitive *primitive, Model *model, std::string *err, const Value &dracoExtensionValue)
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{
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auto bufferViewValue = dracoExtensionValue.Get("bufferView");
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if (!bufferViewValue.IsInt())
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return false;
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auto attributesValue = dracoExtensionValue.Get("attributes");
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if (!attributesValue.IsObject())
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return false;
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auto attributesObject = attributesValue.Get<Value::Object>();
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int bufferView = bufferViewValue.Get<int>();
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BufferView& view = model->bufferViews[bufferView];
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Buffer& buffer = model->buffers[view.buffer];
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// BufferView has already been decoded
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if (view.dracoDecoded)
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return true;
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view.dracoDecoded = true;
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const char* bufferViewData = reinterpret_cast<const char*>(buffer.data.data() + view.byteOffset);
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size_t bufferViewSize = view.byteLength;
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// decode draco
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draco::DecoderBuffer decoderBuffer;
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decoderBuffer.Init(bufferViewData, bufferViewSize);
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draco::Decoder decoder;
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auto decodeResult = decoder.DecodeMeshFromBuffer(&decoderBuffer);
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if (!decodeResult.ok()) {
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return false;
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}
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const std::unique_ptr<draco::Mesh>& mesh = decodeResult.value();
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// create new bufferView for indices
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if (primitive->indices >= 0)
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{
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int32_t componentSize = GetComponentSizeInBytes(model->accessors[primitive->indices].componentType);
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Buffer decodedIndexBuffer;
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decodedIndexBuffer.data.resize(mesh->num_faces() * 3 * componentSize);
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DecodeIndexBuffer(mesh.get(), componentSize, decodedIndexBuffer.data);
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model->buffers.emplace_back(std::move(decodedIndexBuffer));
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BufferView decodedIndexBufferView;
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decodedIndexBufferView.buffer = int(model->buffers.size() - 1);
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decodedIndexBufferView.byteLength = int(mesh->num_faces() * 3 * componentSize);
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decodedIndexBufferView.byteOffset = 0;
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decodedIndexBufferView.byteStride = 0;
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decodedIndexBufferView.target = TINYGLTF_TARGET_ARRAY_BUFFER;
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model->bufferViews.emplace_back(std::move(decodedIndexBufferView));
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model->accessors[primitive->indices].bufferView = int(model->bufferViews.size() - 1);
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}
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for (const auto& attribute : attributesObject)
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{
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if (!attribute.second.IsInt())
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return false;
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int dracoAttributeIndex = attribute.second.Get<int>();
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const auto pAttribute = mesh->GetAttributeByUniqueId(dracoAttributeIndex);
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const auto pBuffer = pAttribute->buffer();
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// Create a new buffer for this decoded buffer
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Buffer decodedBuffer;
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size_t bufferSize = mesh->num_points() * pAttribute->num_components() * draco::DataTypeLength(pAttribute->data_type());
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decodedBuffer.data.resize(bufferSize);
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if (!GetAttributeForAllPoints(mesh.get(), pAttribute, decodedBuffer.data))
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return false;
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model->buffers.emplace_back(std::move(decodedBuffer));
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BufferView decodedBufferView;
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decodedBufferView.buffer = int(model->buffers.size() - 1);
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decodedBufferView.byteLength = bufferSize;
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decodedBufferView.byteOffset = pAttribute->byte_offset();
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decodedBufferView.byteStride = pAttribute->byte_stride();
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decodedBufferView.target = primitive->indices >= 0 ? TINYGLTF_TARGET_ELEMENT_ARRAY_BUFFER : TINYGLTF_TARGET_ARRAY_BUFFER;
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model->bufferViews.emplace_back(std::move(decodedBufferView));
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auto primitiveAttribute = primitive->attributes.find(attribute.first);
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if (primitiveAttribute != primitive->attributes.end())
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{
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model->accessors[primitiveAttribute->second].bufferView = int(model->bufferViews.size() - 1);
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}
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}
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return true;
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}
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#endif
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static bool ParsePrimitive(Primitive *primitive, Model *model, std::string *err,
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const json &o) {
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double material = -1.0;
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ParseNumberProperty(&material, err, o, "material", false);
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@ -2853,10 +3039,20 @@ static bool ParsePrimitive(Primitive *primitive, std::string *err,
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ParseExtrasProperty(&(primitive->extras), o);
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ParseExtensionsProperty(&primitive->extensions, err, o);
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#ifdef TINYGLTF_ENABLE_DRACO
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auto dracoExtension = primitive->extensions.find("KHR_draco_mesh_compression");
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if (dracoExtension != primitive->extensions.end())
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{
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ParseDracoExtension(primitive, model, err, dracoExtension->second);
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}
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#endif
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return true;
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}
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static bool ParseMesh(Mesh *mesh, std::string *err, const json &o) {
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static bool ParseMesh(Mesh *mesh, Model *model, std::string *err, const json &o) {
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ParseStringProperty(&mesh->name, err, o, "name", false);
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mesh->primitives.clear();
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@ -2865,7 +3061,7 @@ static bool ParseMesh(Mesh *mesh, std::string *err, const json &o) {
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for (json::const_iterator i = primObject.value().begin();
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i != primObject.value().end(); i++) {
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Primitive primitive;
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if (ParsePrimitive(&primitive, err, i.value())) {
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if (ParsePrimitive(&primitive, model, err, i.value())) {
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// Only add the primitive if the parsing succeeds.
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mesh->primitives.push_back(primitive);
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}
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@ -3524,7 +3720,7 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
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return false;
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}
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Mesh mesh;
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if (!ParseMesh(&mesh, err, it->get<json>())) {
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if (!ParseMesh(&mesh, model, err, it->get<json>())) {
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return false;
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}
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