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Diffstat (limited to 'extern/draco/draco/src/draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_decoder.h')
| -rw-r--r-- | extern/draco/draco/src/draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_decoder.h | 231 |
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diff --git a/extern/draco/draco/src/draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_decoder.h b/extern/draco/draco/src/draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_decoder.h new file mode 100644 index 00000000000..36c124baa83 --- /dev/null +++ b/extern/draco/draco/src/draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_decoder.h @@ -0,0 +1,231 @@ +// Copyright 2016 The Draco Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +#ifndef DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_CONSTRAINED_MULTI_PARALLELOGRAM_DECODER_H_ +#define DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_CONSTRAINED_MULTI_PARALLELOGRAM_DECODER_H_ + +#include <algorithm> +#include <cmath> + +#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_constrained_multi_parallelogram_shared.h" +#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_decoder.h" +#include "draco/compression/attributes/prediction_schemes/mesh_prediction_scheme_parallelogram_shared.h" +#include "draco/compression/bit_coders/rans_bit_decoder.h" +#include "draco/core/varint_decoding.h" +#include "draco/draco_features.h" + +namespace draco { + +// Decoder for predictions encoded with the constrained multi-parallelogram +// encoder. See the corresponding encoder for more details about the prediction +// method. +template <typename DataTypeT, class TransformT, class MeshDataT> +class MeshPredictionSchemeConstrainedMultiParallelogramDecoder + : public MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT> { + public: + using CorrType = + typename PredictionSchemeDecoder<DataTypeT, TransformT>::CorrType; + using CornerTable = typename MeshDataT::CornerTable; + + explicit MeshPredictionSchemeConstrainedMultiParallelogramDecoder( + const PointAttribute *attribute) + : MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT>( + attribute), + selected_mode_(Mode::OPTIMAL_MULTI_PARALLELOGRAM) {} + MeshPredictionSchemeConstrainedMultiParallelogramDecoder( + const PointAttribute *attribute, const TransformT &transform, + const MeshDataT &mesh_data) + : MeshPredictionSchemeDecoder<DataTypeT, TransformT, MeshDataT>( + attribute, transform, mesh_data), + selected_mode_(Mode::OPTIMAL_MULTI_PARALLELOGRAM) {} + + bool ComputeOriginalValues(const CorrType *in_corr, DataTypeT *out_data, + int size, int num_components, + const PointIndex *entry_to_point_id_map) override; + + bool DecodePredictionData(DecoderBuffer *buffer) override; + + PredictionSchemeMethod GetPredictionMethod() const override { + return MESH_PREDICTION_CONSTRAINED_MULTI_PARALLELOGRAM; + } + + bool IsInitialized() const override { + return this->mesh_data().IsInitialized(); + } + + private: + typedef constrained_multi_parallelogram::Mode Mode; + static constexpr int kMaxNumParallelograms = + constrained_multi_parallelogram::kMaxNumParallelograms; + // Crease edges are used to store whether any given edge should be used for + // parallelogram prediction or not. New values are added in the order in which + // the edges are processed. For better compression, the flags are stored in + // in separate contexts based on the number of available parallelograms at a + // given vertex. + std::vector<bool> is_crease_edge_[kMaxNumParallelograms]; + Mode selected_mode_; +}; + +template <typename DataTypeT, class TransformT, class MeshDataT> +bool MeshPredictionSchemeConstrainedMultiParallelogramDecoder< + DataTypeT, TransformT, MeshDataT>:: + ComputeOriginalValues(const CorrType *in_corr, DataTypeT *out_data, + int /* size */, int num_components, + const PointIndex * /* entry_to_point_id_map */) { + this->transform().Init(num_components); + + // Predicted values for all simple parallelograms encountered at any given + // vertex. + std::vector<DataTypeT> pred_vals[kMaxNumParallelograms]; + for (int i = 0; i < kMaxNumParallelograms; ++i) { + pred_vals[i].resize(num_components, 0); + } + this->transform().ComputeOriginalValue(pred_vals[0].data(), in_corr, + out_data); + + const CornerTable *const table = this->mesh_data().corner_table(); + const std::vector<int32_t> *const vertex_to_data_map = + this->mesh_data().vertex_to_data_map(); + + // Current position in the |is_crease_edge_| array for each context. + std::vector<int> is_crease_edge_pos(kMaxNumParallelograms, 0); + + // Used to store predicted value for multi-parallelogram prediction. + std::vector<DataTypeT> multi_pred_vals(num_components); + + const int corner_map_size = + static_cast<int>(this->mesh_data().data_to_corner_map()->size()); + for (int p = 1; p < corner_map_size; ++p) { + const CornerIndex start_corner_id = + this->mesh_data().data_to_corner_map()->at(p); + + CornerIndex corner_id(start_corner_id); + int num_parallelograms = 0; + bool first_pass = true; + while (corner_id != kInvalidCornerIndex) { + if (ComputeParallelogramPrediction( + p, corner_id, table, *vertex_to_data_map, out_data, + num_components, &(pred_vals[num_parallelograms][0]))) { + // Parallelogram prediction applied and stored in + // |pred_vals[num_parallelograms]| + ++num_parallelograms; + // Stop processing when we reach the maximum number of allowed + // parallelograms. + if (num_parallelograms == kMaxNumParallelograms) { + break; + } + } + + // Proceed to the next corner attached to the vertex. First swing left + // and if we reach a boundary, swing right from the start corner. + if (first_pass) { + corner_id = table->SwingLeft(corner_id); + } else { + corner_id = table->SwingRight(corner_id); + } + if (corner_id == start_corner_id) { + break; + } + if (corner_id == kInvalidCornerIndex && first_pass) { + first_pass = false; + corner_id = table->SwingRight(start_corner_id); + } + } + + // Check which of the available parallelograms are actually used and compute + // the final predicted value. + int num_used_parallelograms = 0; + if (num_parallelograms > 0) { + for (int i = 0; i < num_components; ++i) { + multi_pred_vals[i] = 0; + } + // Check which parallelograms are actually used. + for (int i = 0; i < num_parallelograms; ++i) { + const int context = num_parallelograms - 1; + const int pos = is_crease_edge_pos[context]++; + if (is_crease_edge_[context].size() <= pos) { + return false; + } + const bool is_crease = is_crease_edge_[context][pos]; + if (!is_crease) { + ++num_used_parallelograms; + for (int j = 0; j < num_components; ++j) { + multi_pred_vals[j] += pred_vals[i][j]; + } + } + } + } + const int dst_offset = p * num_components; + if (num_used_parallelograms == 0) { + // No parallelogram was valid. + // We use the last decoded point as a reference. + const int src_offset = (p - 1) * num_components; + this->transform().ComputeOriginalValue( + out_data + src_offset, in_corr + dst_offset, out_data + dst_offset); + } else { + // Compute the correction from the predicted value. + for (int c = 0; c < num_components; ++c) { + multi_pred_vals[c] /= num_used_parallelograms; + } + this->transform().ComputeOriginalValue( + multi_pred_vals.data(), in_corr + dst_offset, out_data + dst_offset); + } + } + return true; +} + +template <typename DataTypeT, class TransformT, class MeshDataT> +bool MeshPredictionSchemeConstrainedMultiParallelogramDecoder< + DataTypeT, TransformT, MeshDataT>::DecodePredictionData(DecoderBuffer + *buffer) { +#ifdef DRACO_BACKWARDS_COMPATIBILITY_SUPPORTED + if (buffer->bitstream_version() < DRACO_BITSTREAM_VERSION(2, 2)) { + // Decode prediction mode. + uint8_t mode; + if (!buffer->Decode(&mode)) { + return false; + } + + if (mode != Mode::OPTIMAL_MULTI_PARALLELOGRAM) { + // Unsupported mode. + return false; + } + } +#endif + + // Encode selected edges using separate rans bit coder for each context. + for (int i = 0; i < kMaxNumParallelograms; ++i) { + uint32_t num_flags; + if (!DecodeVarint<uint32_t>(&num_flags, buffer)) { + return false; + } + if (num_flags > 0) { + is_crease_edge_[i].resize(num_flags); + RAnsBitDecoder decoder; + if (!decoder.StartDecoding(buffer)) { + return false; + } + for (uint32_t j = 0; j < num_flags; ++j) { + is_crease_edge_[i][j] = decoder.DecodeNextBit(); + } + decoder.EndDecoding(); + } + } + return MeshPredictionSchemeDecoder<DataTypeT, TransformT, + MeshDataT>::DecodePredictionData(buffer); +} + +} // namespace draco + +#endif // DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_MESH_PREDICTION_SCHEME_CONSTRAINED_MULTI_PARALLELOGRAM_DECODER_H_ |