Differential D4501 Diff 14126 extern/gltf-draco/draco/src/draco/compression/mesh/traverser/mesh_traversal_sequencer.h

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extern/gltf-draco/draco/src/draco/compression/mesh/traverser/mesh_traversal_sequencer.h

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				// 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_MESH_TRAVERSER_MESH_TRAVERSAL_SEQUENCER_H_
				#define DRACO_COMPRESSION_MESH_TRAVERSER_MESH_TRAVERSAL_SEQUENCER_H_

				#include "draco/attributes/geometry_indices.h"
				#include "draco/compression/attributes/mesh_attribute_indices_encoding_data.h"
				#include "draco/compression/attributes/points_sequencer.h"
				#include "draco/mesh/mesh.h"

				namespace draco {

				// Sequencer that generates point sequence in an order given by a deterministic
				// traversal on the mesh surface. Note that all attributes encoded with this
				// sequence must share the same connectivity.
				// TODO(hemmer): Consider refactoring such that this is an observer.
				template <class TraverserT>
				class MeshTraversalSequencer : public PointsSequencer {
				public:
				MeshTraversalSequencer(const Mesh *mesh,
				const MeshAttributeIndicesEncodingData *encoding_data)
				: mesh_(mesh), encoding_data_(encoding_data), corner_order_(nullptr) {}
				void SetTraverser(const TraverserT &t) { traverser_ = t; }

				// Function that can be used to set an order in which the mesh corners should
				// be processed. This is an optional flag used usually only by the encoder
				// to match the same corner order that is going to be used by the decoder.
				// Note that \|corner_order\| should contain only one corner per face (it can
				// have all corners but only the first encountered corner for each face is
				// going to be used to start a traversal). If the corner order is not set, the
				// corners are processed sequentially based on their ids.
				void SetCornerOrder(const std::vector<CornerIndex> &corner_order) {
				corner_order_ = &corner_order;
				}

				bool UpdatePointToAttributeIndexMapping(PointAttribute *attribute) override {
				const auto *corner_table = traverser_.corner_table();
				attribute->SetExplicitMapping(mesh_->num_points());
				const size_t num_faces = mesh_->num_faces();
				const size_t num_points = mesh_->num_points();
				for (FaceIndex f(0); f < static_cast<uint32_t>(num_faces); ++f) {
				const auto &face = mesh_->face(f);
				for (int p = 0; p < 3; ++p) {
				const PointIndex point_id = face[p];
				const VertexIndex vert_id =
				corner_table->Vertex(CornerIndex(3 * f.value() + p));
				if (vert_id == kInvalidVertexIndex)
				return false;
				const AttributeValueIndex att_entry_id(
				encoding_data_
				->vertex_to_encoded_attribute_value_index_map[vert_id.value()]);
				if (att_entry_id.value() >= num_points) {
				// There cannot be more attribute values than the number of points.
				return false;
				}
				attribute->SetPointMapEntry(point_id, att_entry_id);
				}
				}
				return true;
				}

				protected:
				bool GenerateSequenceInternal() override {
				// Preallocate memory for storing point indices. We expect the number of
				// points to be the same as the number of corner table vertices.
				out_point_ids()->reserve(traverser_.corner_table()->num_vertices());

				traverser_.OnTraversalStart();
				if (corner_order_) {
				for (uint32_t i = 0; i < corner_order_->size(); ++i) {
				if (!ProcessCorner(corner_order_->at(i)))
				return false;
				}
				} else {
				const int32_t num_faces = traverser_.corner_table()->num_faces();
				for (int i = 0; i < num_faces; ++i) {
				if (!ProcessCorner(CornerIndex(3 * i)))
				return false;
				}
				}
				traverser_.OnTraversalEnd();
				return true;
				}

				private:
				bool ProcessCorner(CornerIndex corner_id) {
				return traverser_.TraverseFromCorner(corner_id);
				}

				TraverserT traverser_;
				const Mesh *mesh_;
				const MeshAttributeIndicesEncodingData *encoding_data_;
				const std::vector<CornerIndex> *corner_order_;
				};

				} // namespace draco

				#endif // DRACO_COMPRESSION_MESH_TRAVERSER_MESH_TRAVERSAL_SEQUENCER_H_