void glTFExporter::ExportMeshes()
{
// Not for
// using IndicesType = decltype(aiFace::mNumIndices);
// But yes for
// using IndicesType = unsigned short;
// because "ComponentType_UNSIGNED_SHORT" used for indices. And it's a maximal type according to glTF specification.
typedef unsigned short IndicesType;
// Variables needed for compression. BEGIN.
// Indices, not pointers - because pointer to buffer is changing while writing to it.
size_t idx_srcdata_begin = 0; // Index of buffer before writing mesh data. Also, index of begin of coordinates array in buffer.
size_t idx_srcdata_normal = SIZE_MAX;// Index of begin of normals array in buffer. SIZE_MAX - mean that mesh has no normals.
std::vector<size_t> idx_srcdata_tc;// Array of indices. Every index point to begin of texture coordinates array in buffer.
size_t idx_srcdata_ind;// Index of begin of coordinates indices array in buffer.
bool comp_allow;// Point that data of current mesh can be compressed.
// Variables needed for compression. END.
std::string fname = std::string(mFilename);
std::string bufferIdPrefix = fname.substr(0, fname.rfind(".gltf"));
std::string bufferId = mAsset->FindUniqueID("", bufferIdPrefix.c_str());
Ref<Buffer> b = mAsset->GetBodyBuffer();
if (!b) {
b = mAsset->buffers.Create(bufferId);
}
//----------------------------------------
// Initialize variables for the skin
bool createSkin = false;
for (unsigned int idx_mesh = 0; idx_mesh < mScene->mNumMeshes; ++idx_mesh) {
const aiMesh* aim = mScene->mMeshes[idx_mesh];
if(aim->HasBones()) {
createSkin = true;
break;
}
}
Ref<Skin> skinRef;
std::string skinName = mAsset->FindUniqueID("skin", "skin");
std::vector<aiMatrix4x4> inverseBindMatricesData;
if(createSkin) {
skinRef = mAsset->skins.Create(skinName);
skinRef->name = skinName;
}
//----------------------------------------
for (unsigned int idx_mesh = 0; idx_mesh < mScene->mNumMeshes; ++idx_mesh) {
const aiMesh* aim = mScene->mMeshes[idx_mesh];
// Check if compressing requested and mesh can be encoded.
#ifdef ASSIMP_IMPORTER_GLTF_USE_OPEN3DGC
comp_allow = mProperties->GetPropertyBool("extensions.Open3DGC.use", false);
#else
comp_allow = false;
#endif
if(comp_allow && (aim->mPrimitiveTypes == aiPrimitiveType_TRIANGLE) && (aim->mNumVertices > 0) && (aim->mNumFaces > 0))
{
idx_srcdata_tc.clear();
idx_srcdata_tc.reserve(AI_MAX_NUMBER_OF_TEXTURECOORDS);
}
else
{
std::string msg;
if(aim->mPrimitiveTypes != aiPrimitiveType_TRIANGLE)
msg = "all primitives of the mesh must be a triangles.";
else
msg = "mesh must has vertices and faces.";
ASSIMP_LOG_WARN_F("GLTF: can not use Open3DGC-compression: ", msg);
comp_allow = false;
}
std::string meshId = mAsset->FindUniqueID(aim->mName.C_Str(), "mesh");
Ref<Mesh> m = mAsset->meshes.Create(meshId);
m->primitives.resize(1);
Mesh::Primitive& p = m->primitives.back();
p.material = mAsset->materials.Get(aim->mMaterialIndex);
/******************* Vertices ********************/
// If compression is used then you need parameters of uncompressed region: begin and size. At this step "begin" is stored.
if(comp_allow) idx_srcdata_begin = b->byteLength;
Ref<Accessor> v = ExportData(*mAsset, meshId, b, aim->mNumVertices, aim->mVertices, AttribType::VEC3, AttribType::VEC3, ComponentType_FLOAT);
if (v) p.attributes.position.push_back(v);
/******************** Normals ********************/
if(comp_allow && (aim->mNormals != 0)) idx_srcdata_normal = b->byteLength;// Store index of normals array.
Ref<Accessor> n = ExportData(*mAsset, meshId, b, aim->mNumVertices, aim->mNormals, AttribType::VEC3, AttribType::VEC3, ComponentType_FLOAT);
if (n) p.attributes.normal.push_back(n);
/************** Texture coordinates **************/
for (int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
// Flip UV y coords
if (aim -> mNumUVComponents[i] > 1) {
for (unsigned int j = 0; j < aim->mNumVertices; ++j) {
aim->mTextureCoords[i][j].y = 1 - aim->mTextureCoords[i][j].y;
}
}
if (aim->mNumUVComponents[i] > 0) {
AttribType::Value type = (aim->mNumUVComponents[i] == 2) ? AttribType::VEC2 : AttribType::VEC3;
if(comp_allow) idx_srcdata_tc.push_back(b->byteLength);// Store index of texture coordinates array.
Ref<Accessor> tc = ExportData(*mAsset, meshId, b, aim->mNumVertices, aim->mTextureCoords[i], AttribType::VEC3, type, ComponentType_FLOAT, false);
if (tc) p.attributes.texcoord.push_back(tc);
}
}
/*************** Vertices indices ****************/
idx_srcdata_ind = b->byteLength;// Store index of indices array.
if (aim->mNumFaces > 0) {
std::vector<IndicesType> indices;
unsigned int nIndicesPerFace = aim->mFaces[0].mNumIndices;
indices.resize(aim->mNumFaces * nIndicesPerFace);
for (size_t i = 0; i < aim->mNumFaces; ++i) {
for (size_t j = 0; j < nIndicesPerFace; ++j) {
indices[i*nIndicesPerFace + j] = uint16_t(aim->mFaces[i].mIndices[j]);
}
}
p.indices = ExportData(*mAsset, meshId, b, unsigned(indices.size()), &indices[0], AttribType::SCALAR, AttribType::SCALAR, ComponentType_UNSIGNED_SHORT, true);
}
switch (aim->mPrimitiveTypes) {
case aiPrimitiveType_POLYGON:
p.mode = PrimitiveMode_TRIANGLES; break; // TODO implement this
case aiPrimitiveType_LINE:
p.mode = PrimitiveMode_LINES; break;
case aiPrimitiveType_POINT:
p.mode = PrimitiveMode_POINTS; break;
default: // aiPrimitiveType_TRIANGLE
p.mode = PrimitiveMode_TRIANGLES;
}
/*************** Skins ****************/
if(aim->HasBones()) {
ExportSkin(*mAsset, aim, m, b, skinRef, inverseBindMatricesData);
}
/****************** Compression ******************/
///TODO: animation: weights, joints.
if(comp_allow)
{
#ifdef ASSIMP_IMPORTER_GLTF_USE_OPEN3DGC
// Only one type of compression supported at now - Open3DGC.
//
o3dgc::BinaryStream bs;
o3dgc::SC3DMCEncoder<IndicesType> encoder;
o3dgc::IndexedFaceSet<IndicesType> comp_o3dgc_ifs;
o3dgc::SC3DMCEncodeParams comp_o3dgc_params;
//
// Fill data for encoder.
//
// Quantization
unsigned quant_coord = mProperties->GetPropertyInteger("extensions.Open3DGC.quantization.POSITION", 12);
unsigned quant_normal = mProperties->GetPropertyInteger("extensions.Open3DGC.quantization.NORMAL", 10);
unsigned quant_texcoord = mProperties->GetPropertyInteger("extensions.Open3DGC.quantization.TEXCOORD", 10);
// Prediction
o3dgc::O3DGCSC3DMCPredictionMode prediction_position = o3dgc::O3DGC_SC3DMC_PARALLELOGRAM_PREDICTION;
o3dgc::O3DGCSC3DMCPredictionMode prediction_normal = o3dgc::O3DGC_SC3DMC_SURF_NORMALS_PREDICTION;
o3dgc::O3DGCSC3DMCPredictionMode prediction_texcoord = o3dgc::O3DGC_SC3DMC_PARALLELOGRAM_PREDICTION;
// IndexedFacesSet: "Crease angle", "solid", "convex" are set to default.
comp_o3dgc_ifs.SetCCW(true);
comp_o3dgc_ifs.SetIsTriangularMesh(true);
comp_o3dgc_ifs.SetNumFloatAttributes(0);
// Coordinates
comp_o3dgc_params.SetCoordQuantBits(quant_coord);
comp_o3dgc_params.SetCoordPredMode(prediction_position);
comp_o3dgc_ifs.SetNCoord(aim->mNumVertices);
comp_o3dgc_ifs.SetCoord((o3dgc::Real* const)&b->GetPointer()[idx_srcdata_begin]);
// Normals
if(idx_srcdata_normal != SIZE_MAX)
{
comp_o3dgc_params.SetNormalQuantBits(quant_normal);
comp_o3dgc_params.SetNormalPredMode(prediction_normal);
comp_o3dgc_ifs.SetNNormal(aim->mNumVertices);
comp_o3dgc_ifs.SetNormal((o3dgc::Real* const)&b->GetPointer()[idx_srcdata_normal]);
}
// Texture coordinates
for(size_t num_tc = 0; num_tc < idx_srcdata_tc.size(); num_tc++)
{
size_t num = comp_o3dgc_ifs.GetNumFloatAttributes();
comp_o3dgc_params.SetFloatAttributeQuantBits(static_cast<unsigned long>(num), quant_texcoord);
comp_o3dgc_params.SetFloatAttributePredMode(static_cast<unsigned long>(num), prediction_texcoord);
comp_o3dgc_ifs.SetNFloatAttribute(static_cast<unsigned long>(num), aim->mNumVertices);// number of elements.
comp_o3dgc_ifs.SetFloatAttributeDim(static_cast<unsigned long>(num), aim->mNumUVComponents[num_tc]);// components per element: aiVector3D => x * float
comp_o3dgc_ifs.SetFloatAttributeType(static_cast<unsigned long>(num), o3dgc::O3DGC_IFS_FLOAT_ATTRIBUTE_TYPE_TEXCOORD);
comp_o3dgc_ifs.SetFloatAttribute(static_cast<unsigned long>(num), (o3dgc::Real* const)&b->GetPointer()[idx_srcdata_tc[num_tc]]);
comp_o3dgc_ifs.SetNumFloatAttributes(static_cast<unsigned long>(num + 1));
}
// Coordinates indices
comp_o3dgc_ifs.SetNCoordIndex(aim->mNumFaces);
comp_o3dgc_ifs.SetCoordIndex((IndicesType* const)&b->GetPointer()[idx_srcdata_ind]);
// Prepare to encoding
comp_o3dgc_params.SetNumFloatAttributes(comp_o3dgc_ifs.GetNumFloatAttributes());
if(mProperties->GetPropertyBool("extensions.Open3DGC.binary", true))
comp_o3dgc_params.SetStreamType(o3dgc::O3DGC_STREAM_TYPE_BINARY);
else
comp_o3dgc_params.SetStreamType(o3dgc::O3DGC_STREAM_TYPE_ASCII);
comp_o3dgc_ifs.ComputeMinMax(o3dgc::O3DGC_SC3DMC_MAX_ALL_DIMS);
//
// Encoding
//
encoder.Encode(comp_o3dgc_params, comp_o3dgc_ifs, bs);
// Replace data in buffer.
b->ReplaceData(idx_srcdata_begin, b->byteLength - idx_srcdata_begin, bs.GetBuffer(), bs.GetSize());
//
// Add information about extension to mesh.
//
// Create extension structure.
Mesh::SCompression_Open3DGC* ext = new Mesh::SCompression_Open3DGC;
// Fill it.
ext->Buffer = b->id;
ext->Offset = idx_srcdata_begin;
ext->Count = b->byteLength - idx_srcdata_begin;
ext->Binary = mProperties->GetPropertyBool("extensions.Open3DGC.binary");
ext->IndicesCount = comp_o3dgc_ifs.GetNCoordIndex() * 3;
ext->VerticesCount = comp_o3dgc_ifs.GetNCoord();
// And assign to mesh.
m->Extension.push_back(ext);
#endif
}// if(comp_allow)
}// for (unsigned int i = 0; i < mScene->mNumMeshes; ++i)
//----------------------------------------
// Finish the skin
// Create the Accessor for skinRef->inverseBindMatrices
if (createSkin) {
mat4* invBindMatrixData = new mat4[inverseBindMatricesData.size()];
for ( unsigned int idx_joint = 0; idx_joint < inverseBindMatricesData.size(); ++idx_joint) {
CopyValue(inverseBindMatricesData[idx_joint], invBindMatrixData[idx_joint]);
}
Ref<Accessor> invBindMatrixAccessor = ExportData(*mAsset, skinName, b, static_cast<unsigned int>(inverseBindMatricesData.size()), invBindMatrixData, AttribType::MAT4, AttribType::MAT4, ComponentType_FLOAT);
if (invBindMatrixAccessor) skinRef->inverseBindMatrices = invBindMatrixAccessor;
// Identity Matrix =====> skinRef->bindShapeMatrix
// Temporary. Hard-coded identity matrix here
skinRef->bindShapeMatrix.isPresent = true;
IdentityMatrix4(skinRef->bindShapeMatrix.value);
// Find node that contains this mesh and add "skeletons" and "skin" attributes to that node.
Ref<Node> rootNode = mAsset->nodes.Get(unsigned(0));
Ref<Node> meshNode;
std::string meshID = mAsset->meshes.Get(unsigned(0))->id;
FindMeshNode(rootNode, meshNode, meshID);
Ref<Node> rootJoint = FindSkeletonRootJoint(skinRef);
meshNode->skeletons.push_back(rootJoint);
meshNode->skin = skinRef;
}
}
