1 files changed, 164 insertions, 0 deletions
diff --git a/extern/draco/draco/src/draco/compression/mesh/mesh_sequential_decoder.cc b/extern/draco/draco/src/draco/compression/mesh/mesh_sequential_decoder.cc
new file mode 100644
index 00000000000..53f5e8651b8
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+++ b/extern/draco/draco/src/draco/compression/mesh/mesh_sequential_decoder.cc
@@ -0,0 +1,164 @@
+// 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_decoder.h"
+
+#include "draco/compression/attributes/linear_sequencer.h"
+#include "draco/compression/attributes/sequential_attribute_decoders_controller.h"
+#include "draco/compression/entropy/symbol_decoding.h"
+#include "draco/core/varint_decoding.h"
+
+namespace draco {
+
+MeshSequentialDecoder::MeshSequentialDecoder() {}
+
+bool MeshSequentialDecoder::DecodeConnectivity() {
+  uint32_t num_faces;
+  uint32_t num_points;
+#ifdef DRACO_BACKWARDS_COMPATIBILITY_SUPPORTED
+  if (bitstream_version() < DRACO_BITSTREAM_VERSION(2, 2)) {
+    if (!buffer()->Decode(&num_faces)) {
+      return false;
+    }
+    if (!buffer()->Decode(&num_points)) {
+      return false;
+    }
+
+  } else
+#endif
+  {
+    if (!DecodeVarint(&num_faces, buffer())) {
+      return false;
+    }
+    if (!DecodeVarint(&num_points, buffer())) {
+      return false;
+    }
+  }
+
+  // Check that num_faces and num_points are valid values.
+  const uint64_t faces_64 = static_cast<uint64_t>(num_faces);
+  const uint64_t points_64 = static_cast<uint64_t>(num_points);
+  // Compressed sequential encoding can only handle (2^32 - 1) / 3 indices.
+  if (faces_64 > 0xffffffff / 3) {
+    return false;
+  }
+  if (points_64 > faces_64 * 3) {
+    return false;
+  }
+  uint8_t connectivity_method;
+  if (!buffer()->Decode(&connectivity_method)) {
+    return false;
+  }
+  if (connectivity_method == 0) {
+    if (!DecodeAndDecompressIndices(num_faces)) {
+      return false;
+    }
+  } else {
+    if (num_points < 256) {
+      // Decode indices as uint8_t.
+      for (uint32_t i = 0; i < num_faces; ++i) {
+        Mesh::Face face;
+        for (int j = 0; j < 3; ++j) {
+          uint8_t val;
+          if (!buffer()->Decode(&val)) {
+            return false;
+          }
+          face[j] = val;
+        }
+        mesh()->AddFace(face);
+      }
+    } else if (num_points < (1 << 16)) {
+      // Decode indices as uint16_t.
+      for (uint32_t i = 0; i < num_faces; ++i) {
+        Mesh::Face face;
+        for (int j = 0; j < 3; ++j) {
+          uint16_t val;
+          if (!buffer()->Decode(&val)) {
+            return false;
+          }
+          face[j] = val;
+        }
+        mesh()->AddFace(face);
+      }
+    } else if (mesh()->num_points() < (1 << 21) &&
+               bitstream_version() >= DRACO_BITSTREAM_VERSION(2, 2)) {
+      // Decode indices as uint32_t.
+      for (uint32_t i = 0; i < num_faces; ++i) {
+        Mesh::Face face;
+        for (int j = 0; j < 3; ++j) {
+          uint32_t val;
+          if (!DecodeVarint(&val, buffer())) {
+            return false;
+          }
+          face[j] = val;
+        }
+        mesh()->AddFace(face);
+      }
+    } else {
+      // Decode faces as uint32_t (default).
+      for (uint32_t i = 0; i < num_faces; ++i) {
+        Mesh::Face face;
+        for (int j = 0; j < 3; ++j) {
+          uint32_t val;
+          if (!buffer()->Decode(&val)) {
+            return false;
+          }
+          face[j] = val;
+        }
+        mesh()->AddFace(face);
+      }
+    }
+  }
+  point_cloud()->set_num_points(num_points);
+  return true;
+}
+
+bool MeshSequentialDecoder::CreateAttributesDecoder(int32_t att_decoder_id) {
+  // Always create the basic attribute decoder.
+  return SetAttributesDecoder(
+      att_decoder_id,
+      std::unique_ptr<AttributesDecoder>(
+          new SequentialAttributeDecodersController(
+              std::unique_ptr<PointsSequencer>(
+                  new LinearSequencer(point_cloud()->num_points())))));
+}
+
+bool MeshSequentialDecoder::DecodeAndDecompressIndices(uint32_t num_faces) {
+  // Get decoded indices differences that were encoded with an entropy code.
+  std::vector<uint32_t> indices_buffer(num_faces * 3);
+  if (!DecodeSymbols(num_faces * 3, 1, buffer(), indices_buffer.data())) {
+    return false;
+  }
+  // Reconstruct the indices from the differences.
+  // See MeshSequentialEncoder::CompressAndEncodeIndices() for more details.
+  int32_t last_index_value = 0;
+  int vertex_index = 0;
+  for (uint32_t i = 0; i < num_faces; ++i) {
+    Mesh::Face face;
+    for (int j = 0; j < 3; ++j) {
+      const uint32_t encoded_val = indices_buffer[vertex_index++];
+      int32_t index_diff = (encoded_val >> 1);
+      if (encoded_val & 1) {
+        index_diff = -index_diff;
+      }
+      const int32_t index_value = index_diff + last_index_value;
+      face[j] = index_value;
+      last_index_value = index_value;
+    }
+    mesh()->AddFace(face);
+  }
+  return true;
+}
+
+}  // namespace draco