Differential D4501 Diff 14173 extern/draco/dracoenc/src/draco/compression/mesh/mesh_sequential_encoder.cc

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extern/draco/dracoenc/src/draco/compression/mesh/mesh_sequential_encoder.cc

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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.
				//
				#include "draco/compression/mesh/mesh_sequential_encoder.h"

				#include <cstdlib>

				#include "draco/compression/attributes/linear_sequencer.h"
				#include "draco/compression/attributes/sequential_attribute_encoders_controller.h"
				#include "draco/compression/entropy/symbol_encoding.h"
				#include "draco/core/varint_encoding.h"

				namespace draco {

				MeshSequentialEncoder::MeshSequentialEncoder() {}

				bool MeshSequentialEncoder::EncodeConnectivity() {
				// Serialize indices.
				const uint32_t num_faces = mesh()->num_faces();
				EncodeVarint(num_faces, buffer());
				EncodeVarint(static_cast<uint32_t>(mesh()->num_points()), buffer());

				// We encode all attributes in the original (possibly duplicated) format.
				// TODO(ostava): This may not be optimal if we have only one attribute or if
				// all attributes share the same index mapping.
				if (options()->GetGlobalBool("compress_connectivity", false)) {
				// 0 = Encode compressed indices.
				buffer()->Encode(static_cast<uint8_t>(0));
				if (!CompressAndEncodeIndices())
				return false;
				} else {
				// 1 = Encode indices directly.
				buffer()->Encode(static_cast<uint8_t>(1));
				// Store vertex indices using a smallest data type that fits their range.
				// TODO(ostava): This can be potentially improved by using a tighter
				// fit that is not bound by a bit-length of any particular data type.
				if (mesh()->num_points() < 256) {
				// Serialize indices as uint8_t.
				for (FaceIndex i(0); i < num_faces; ++i) {
				const auto &face = mesh()->face(i);
				buffer()->Encode(static_cast<uint8_t>(face[0].value()));
				buffer()->Encode(static_cast<uint8_t>(face[1].value()));
				buffer()->Encode(static_cast<uint8_t>(face[2].value()));
				}
				} else if (mesh()->num_points() < (1 << 16)) {
				// Serialize indices as uint16_t.
				for (FaceIndex i(0); i < num_faces; ++i) {
				const auto &face = mesh()->face(i);
				buffer()->Encode(static_cast<uint16_t>(face[0].value()));
				buffer()->Encode(static_cast<uint16_t>(face[1].value()));
				buffer()->Encode(static_cast<uint16_t>(face[2].value()));
				}
				} else if (mesh()->num_points() < (1 << 21)) {
				// Serialize indices as varint.
				for (FaceIndex i(0); i < num_faces; ++i) {
				const auto &face = mesh()->face(i);
				EncodeVarint(static_cast<uint32_t>(face[0].value()), buffer());
				EncodeVarint(static_cast<uint32_t>(face[1].value()), buffer());
				EncodeVarint(static_cast<uint32_t>(face[2].value()), buffer());
				}
				} else {
				// Serialize faces as uint32_t (default).
				for (FaceIndex i(0); i < num_faces; ++i) {
				const auto &face = mesh()->face(i);
				buffer()->Encode(face);
				}
				}
				}
				return true;
				}

				bool MeshSequentialEncoder::GenerateAttributesEncoder(int32_t att_id) {
				// Create only one attribute encoder that is going to encode all points in a
				// linear sequence.
				if (att_id == 0) {
				// Create a new attribute encoder only for the first attribute.
				AddAttributesEncoder(std::unique_ptr<AttributesEncoder>(
				new SequentialAttributeEncodersController(
				std::unique_ptr<PointsSequencer>(
				new LinearSequencer(point_cloud()->num_points())),
				att_id)));
				} else {
				// Reuse the existing attribute encoder for other attributes.
				attributes_encoder(0)->AddAttributeId(att_id);
				}
				return true;
				}

				bool MeshSequentialEncoder::CompressAndEncodeIndices() {
				// Collect all indices to a buffer and encode them.
				// Each new index is a difference from the previous value.
				std::vector<uint32_t> indices_buffer;
				int32_t last_index_value = 0;
				const int num_faces = mesh()->num_faces();
				for (FaceIndex i(0); i < num_faces; ++i) {
				const auto &face = mesh()->face(i);
				for (int j = 0; j < 3; ++j) {
				const int32_t index_value = face[j].value();
				const int32_t index_diff = index_value - last_index_value;
				// Encode signed value to an unsigned one (put the sign to lsb pos).
				const uint32_t encoded_val =
				(abs(index_diff) << 1) \| (index_diff < 0 ? 1 : 0);
				indices_buffer.push_back(encoded_val);
				last_index_value = index_value;
				}
				}
				EncodeSymbols(indices_buffer.data(), static_cast<int>(indices_buffer.size()),
				1, nullptr, buffer());
				return true;
				}

				void MeshSequentialEncoder::ComputeNumberOfEncodedPoints() {
				set_num_encoded_points(mesh()->num_points());
				}

				void MeshSequentialEncoder::ComputeNumberOfEncodedFaces() {
				set_num_encoded_faces(mesh()->num_faces());
				}

				} // namespace draco