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https://git.mirrors.martin98.com/https://github.com/google/draco
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85 lines
2.9 KiB
C++
85 lines
2.9 KiB
C++
// Copyright 2016 The Draco Authors.
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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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#ifndef DRACO_COMPRESSION_MESH_MESH_DECODER_HELPERS_H_
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#define DRACO_COMPRESSION_MESH_MESH_DECODER_HELPERS_H_
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#include "compression/mesh/mesh_decoder.h"
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namespace draco {
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// Function for decoding a stream previously encoded by a MeshEncoder. The
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// result is stored into a stream of single precision floating point numbers
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// in a XYZ|UV format, where one value is stored for every corner of each
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// triangle.
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// On error, the function sets the input stream "is" to an invalid state.
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template <typename InStreamT>
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InStreamT &DecodePos3Tex2DataFromStream(InStreamT &&is,
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std::vector<float> *out_data) {
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// Determine the size of the encoded data and write it into a vector.
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auto is_size = is.tellg();
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is.seekg(0, std::ios::end);
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is_size = is.tellg() - is_size;
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is.seekg(0, std::ios::beg);
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std::vector<char> data(is_size);
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is.read(&data[0], is_size);
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// Create a mesh from the data.
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std::unique_ptr<Mesh> mesh = draco::DecodeMesh(&data[0], data.size());
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if (mesh == nullptr) {
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is.setstate(ios_base::badbit);
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return is;
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}
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const PointAttribute *pos_att =
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mesh->GetNamedAttribute(GeometryAttribute::POSITION);
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const PointAttribute *tex_att =
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mesh->GetNamedAttribute(GeometryAttribute::TEX_COORD_0);
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// Both position and texture attributes must be present.
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if (pos_att == nullptr || tex_att == nullptr) {
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is.setstate(ios_base::badbit);
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return is;
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}
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// Copy the mesh data into the provided output.
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constexpr int data_stride = 5;
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// Prepare the output storage for 3 output values per face.
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out_data->resize(mesh->num_faces() * 3 * data_stride);
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std::array<float, 3> pos_val;
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std::array<float, 2> tex_val;
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int out_it = 0;
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for (int f = 0; f < mesh->num_faces(); ++f) {
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const Mesh::Face &face = mesh->face(f);
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for (int p = 0; p < 3; ++p) {
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pos_att->ConvertValue<float, 3>(pos_att->mapped_index(face[p]),
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&pos_val[0]);
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memcpy(&out_data->at(0) + out_it, &pos_val[0], sizeof(pos_val));
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out_it += 3;
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tex_att->ConvertValue<float, 2>(tex_att->mapped_index(face[p]),
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&tex_val[0]);
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memcpy(&out_data->at(0) + out_it, &tex_val[0], sizeof(tex_val));
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out_it += 2;
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}
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}
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return is;
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}
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} // namespace draco
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#endif // DRACO_COMPRESSION_MESH_MESH_DECODER_HELPERS_H_
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