version_(version) {}

        version_(version) {}

  int GetNumParentAttributes() const override { return 1; }

  int GetNumParentAttributes() const override { return 1; }

  GeometryAttribute::Type GetParentAttributeType(int i) const override {

    DRACO_DCHECK_EQ(i, 0);

    (void)i;

    return GeometryAttribute::POSITION;

  }

  GeometryAttribute::Type GetParentAttributeType(int i) const override {

    DRACO_DCHECK_EQ(i, 0);

    (void)i;

    return GeometryAttribute::POSITION;

  }

  bool SetParentAttribute(const PointAttribute *att) override {

    if (att == nullptr) {

      return false;

    }

    if (att->attribute_type() != GeometryAttribute::POSITION) {

      return false;  // Invalid attribute type.

    }

    if (att->num_components() != 3) {

      return false;  // Currently works only for 3 component positions.

    }

    pos_attribute_ = att;

    return true;

  }

  bool SetParentAttribute(const PointAttribute *att) override {

    if (att == nullptr) {

      return false;

    }

    if (att->attribute_type() != GeometryAttribute::POSITION) {

      return false;  // Invalid attribute type.

    }

    if (att->num_components() != 3) {

      return false;  // Currently works only for 3 component positions.

    }

    pos_attribute_ = att;

    return true;

  }

  Vector3f GetPositionForEntryId(int entry_id) const {

    const PointIndex point_id = entry_to_point_id_map_[entry_id];

    Vector3f pos;

    pos_attribute_->ConvertValue(pos_attribute_->mapped_index(point_id),

                                 &pos[0]);

    return pos;

  }

  Vector3f GetPositionForEntryId(int entry_id) const {

    const PointIndex point_id = entry_to_point_id_map_[entry_id];

    Vector3f pos;

    pos_attribute_->ConvertValue(pos_attribute_->mapped_index(point_id),

                                 &pos[0]);

    return pos;

  }

  Vector2f GetTexCoordForEntryId(int entry_id, const DataTypeT *data) const {

    const int data_offset = entry_id * num_components_;

    return Vector2f(static_cast<float>(data[data_offset]),

                    static_cast<float>(data[data_offset + 1]));

  }

  Vector2f GetTexCoordForEntryId(int entry_id, const DataTypeT *data) const {

    const int data_offset = entry_id * num_components_;

    return Vector2f(static_cast<float>(data[data_offset]),

                    static_cast<float>(data[data_offset + 1]));

  }

                          const PointIndex *entry_to_point_id_map) {

  if (num_components != 2) {

    // Corrupt/malformed input. Two output components are req'd.

    return false;

  }

  num_components_ = num_components;

  entry_to_point_id_map_ = entry_to_point_id_map;

  predicted_value_ =

      std::unique_ptr<DataTypeT[]>(new DataTypeT[num_components]);

  this->transform().Init(num_components);

  const int corner_map_size =

      static_cast<int>(this->mesh_data().data_to_corner_map()->size());

  for (int p = 0; p < corner_map_size; ++p) {

    const CornerIndex corner_id = this->mesh_data().data_to_corner_map()->at(p);

    if (!ComputePredictedValue(corner_id, out_data, p)) {

      return false;

    }

    const int dst_offset = p * num_components;

    this->transform().ComputeOriginalValue(

        predicted_value_.get(), in_corr + dst_offset, out_data + dst_offset);

  }

  return true;

}

                          const PointIndex *entry_to_point_id_map) {

  if (num_components != 2) {

    // Corrupt/malformed input. Two output components are req'd.

    return false;

  }

  num_components_ = num_components;

  entry_to_point_id_map_ = entry_to_point_id_map;

  predicted_value_ =

      std::unique_ptr<DataTypeT[]>(new DataTypeT[num_components]);

  this->transform().Init(num_components);

  const int corner_map_size =

      static_cast<int>(this->mesh_data().data_to_corner_map()->size());

  for (int p = 0; p < corner_map_size; ++p) {

    const CornerIndex corner_id = this->mesh_data().data_to_corner_map()->at(p);

    if (!ComputePredictedValue(corner_id, out_data, p)) {

      return false;

    }

    const int dst_offset = p * num_components;

    this->transform().ComputeOriginalValue(

        predicted_value_.get(), in_corr + dst_offset, out_data + dst_offset);

  }

  return true;

}

    DecodePredictionData(DecoderBuffer *buffer) {

  // Decode the delta coded orientations.

  uint32_t num_orientations = 0;

  if (buffer->bitstream_version() < DRACO_BITSTREAM_VERSION(2, 2)) {

    if (!buffer->Decode(&num_orientations)) {

      return false;

    }

  } else {

    if (!DecodeVarint(&num_orientations, buffer)) {

      return false;

    }

  }

  if (num_orientations == 0) {

    return false;

  }

  if (num_orientations > this->mesh_data().corner_table()->num_corners()) {

    // We can't have more orientations than the maximum number of decoded

    // values.

    return false;

  }

  orientations_.resize(num_orientations);

  bool last_orientation = true;

  RAnsBitDecoder decoder;

  if (!decoder.StartDecoding(buffer)) {

    return false;

  }

  for (uint32_t i = 0; i < num_orientations; ++i) {

    if (!decoder.DecodeNextBit()) {

      last_orientation = !last_orientation;

    }

    orientations_[i] = last_orientation;

  }

  decoder.EndDecoding();

  return MeshPredictionSchemeDecoder<DataTypeT, TransformT,

                                     MeshDataT>::DecodePredictionData(buffer);

}

    DecodePredictionData(DecoderBuffer *buffer) {

  // Decode the delta coded orientations.

  uint32_t num_orientations = 0;

  if (buffer->bitstream_version() < DRACO_BITSTREAM_VERSION(2, 2)) {

    if (!buffer->Decode(&num_orientations)) {

      return false;

    }

  } else {

    if (!DecodeVarint(&num_orientations, buffer)) {

      return false;

    }

  }

  if (num_orientations == 0) {

    return false;

  }

  if (num_orientations > this->mesh_data().corner_table()->num_corners()) {

    // We can't have more orientations than the maximum number of decoded

    // values.

    return false;

  }

  orientations_.resize(num_orientations);

  bool last_orientation = true;

  RAnsBitDecoder decoder;

  if (!decoder.StartDecoding(buffer)) {

    return false;

  }

  for (uint32_t i = 0; i < num_orientations; ++i) {

    if (!decoder.DecodeNextBit()) {

      last_orientation = !last_orientation;

    }

    orientations_[i] = last_orientation;

  }

  decoder.EndDecoding();

  return MeshPredictionSchemeDecoder<DataTypeT, TransformT,

                                     MeshDataT>::DecodePredictionData(buffer);

}

                          int data_id) {

  // Compute the predicted UV coordinate from the positions on all corners

  // of the processed triangle. For the best prediction, the UV coordinates

  // on the next/previous corners need to be already encoded/decoded.

  const CornerIndex next_corner_id =

      this->mesh_data().corner_table()->Next(corner_id);

  const CornerIndex prev_corner_id =

      this->mesh_data().corner_table()->Previous(corner_id);

  // Get the encoded data ids from the next and previous corners.

  // The data id is the encoding order of the UV coordinates.

  int next_data_id, prev_data_id;

  int next_vert_id, prev_vert_id;

  next_vert_id =

      this->mesh_data().corner_table()->Vertex(next_corner_id).value();

  prev_vert_id =

      this->mesh_data().corner_table()->Vertex(prev_corner_id).value();

  next_data_id = this->mesh_data().vertex_to_data_map()->at(next_vert_id);

  prev_data_id = this->mesh_data().vertex_to_data_map()->at(prev_vert_id);

  if (prev_data_id < data_id && next_data_id < data_id) {

    // Both other corners have available UV coordinates for prediction.

    const Vector2f n_uv = GetTexCoordForEntryId(next_data_id, data);

    const Vector2f p_uv = GetTexCoordForEntryId(prev_data_id, data);

    if (p_uv == n_uv) {

      // We cannot do a reliable prediction on degenerated UV triangles.

      // Technically floats > INT_MAX are undefined, but compilers will

      // convert those values to INT_MIN. We are being explicit here for asan.

      for (const int i : {0, 1}) {

        if (std::isnan(p_uv[i]) || static_cast<double>(p_uv[i]) > INT_MAX ||

            static_cast<double>(p_uv[i]) < INT_MIN) {

          predicted_value_[i] = INT_MIN;

        } else {

          predicted_value_[i] = static_cast<int>(p_uv[i]);

        }

      }

      return true;

    }

    // Get positions at all corners.

    const Vector3f tip_pos = GetPositionForEntryId(data_id);

    const Vector3f next_pos = GetPositionForEntryId(next_data_id);

    const Vector3f prev_pos = GetPositionForEntryId(prev_data_id);

    // Use the positions of the above triangle to predict the texture coordinate

    // on the tip corner C.

    // Convert the triangle into a new coordinate system defined by orthogonal

    // bases vectors S, T, where S is vector prev_pos - next_pos and T is an

    // perpendicular vector to S in the same plane as vector the

    // tip_pos - next_pos.

    // The transformed triangle in the new coordinate system is then going to

    // be represented as:

    //

    //        1 ^

    //          |

    //          |

    //          |   C

    //          |  /  \

    //          | /      \

    //          |/          \

    //          N--------------P

    //          0              1

    //

    // Where next_pos point (N) is at position (0, 0), prev_pos point (P) is

    // at (1, 0). Our goal is to compute the position of the tip_pos point (C)

    // in this new coordinate space (s, t).

    //

    const Vector3f pn = prev_pos - next_pos;

    const Vector3f cn = tip_pos - next_pos;

    const float pn_norm2_squared = pn.SquaredNorm();

    // Coordinate s of the tip corner C is simply the dot product of the

    // normalized vectors |pn| and |cn| (normalized by the length of |pn|).

    // Since both of these vectors are normalized, we don't need to perform the

    // normalization explicitly and instead we can just use the squared norm

    // of |pn| as a denominator of the resulting dot product of non normalized

    // vectors.

    float s, t;

    // |pn_norm2_squared| can be exactly 0 when the next_pos and prev_pos are

    // the same positions (e.g. because they were quantized to the same

    // location).

    if (version_ < DRACO_BITSTREAM_VERSION(1, 2) || pn_norm2_squared > 0) {

      s = pn.Dot(cn) / pn_norm2_squared;

      // To get the coordinate t, we can use formula:

      //      t = |C-N - (P-N) * s| / |P-N|

      // Do not use std::sqrt to avoid changes in the bitstream.

      t = sqrt((cn - pn * s).SquaredNorm() / pn_norm2_squared);

    } else {

      s = 0;

      t = 0;

    }

    // Now we need to transform the point (s, t) to the texture coordinate space

    // UV. We know the UV coordinates on points N and P (N_UV and P_UV). Lets

    // denote P_UV - N_UV = PN_UV. PN_UV is then 2 dimensional vector that can

    // be used to define transformation from the normalized coordinate system

    // to the texture coordinate system using a 3x3 affine matrix M:

    //

    //  M = | PN_UV[0]  -PN_UV[1]  N_UV[0] |

    //      | PN_UV[1]   PN_UV[0]  N_UV[1] |

    //      | 0          0         1       |

    //

    // The predicted point C_UV in the texture space is then equal to

    // C_UV = M * (s, t, 1). Because the triangle in UV space may be flipped

    // around the PN_UV axis, we also need to consider point C_UV' = M * (s, -t)

    // as the prediction.

    const Vector2f pn_uv = p_uv - n_uv;

    const float pnus = pn_uv[0] * s + n_uv[0];

    const float pnut = pn_uv[0] * t;

    const float pnvs = pn_uv[1] * s + n_uv[1];

    const float pnvt = pn_uv[1] * t;

    Vector2f predicted_uv;

    if (orientations_.empty()) {

      return false;

    }

    // When decoding the data, we already know which orientation to use.

    const bool orientation = orientations_.back();

    orientations_.pop_back();

    if (orientation) {

      predicted_uv = Vector2f(pnus - pnvt, pnvs + pnut);

    } else {

      predicted_uv = Vector2f(pnus + pnvt, pnvs - pnut);

    }

    if (std::is_integral<DataTypeT>::value) {

      // Round the predicted value for integer types.

      // Technically floats > INT_MAX are undefined, but compilers will

      // convert those values to INT_MIN. We are being explicit here for asan.

      const double u = floor(predicted_uv[0] + 0.5);

      if (std::isnan(u) || u > INT_MAX || u < INT_MIN) {

        predicted_value_[0] = INT_MIN;

      } else {

        predicted_value_[0] = static_cast<int>(u);

      }

      const double v = floor(predicted_uv[1] + 0.5);

      if (std::isnan(v) || v > INT_MAX || v < INT_MIN) {

        predicted_value_[1] = INT_MIN;

      } else {

        predicted_value_[1] = static_cast<int>(v);

      }

    } else {

      predicted_value_[0] = static_cast<int>(predicted_uv[0]);

      predicted_value_[1] = static_cast<int>(predicted_uv[1]);

    }

    return true;

  }

  // Else we don't have available textures on both corners. For such case we

  // can't use positions for predicting the uv value and we resort to delta

  // coding.

  int data_offset = 0;

  if (prev_data_id < data_id) {

    // Use the value on the previous corner as the prediction.

    data_offset = prev_data_id * num_components_;

  }

  if (next_data_id < data_id) {

    // Use the value on the next corner as the prediction.

    data_offset = next_data_id * num_components_;

  } else {

    // None of the other corners have a valid value. Use the last encoded value

    // as the prediction if possible.

    if (data_id > 0) {

      data_offset = (data_id - 1) * num_components_;

    } else {

      // We are encoding the first value. Predict 0.

      for (int i = 0; i < num_components_; ++i) {

        predicted_value_[i] = 0;

      }

      return true;

    }

  }

  for (int i = 0; i < num_components_; ++i) {

    predicted_value_[i] = data[data_offset + i];

  }

  return true;

}

                          int data_id) {

  // Compute the predicted UV coordinate from the positions on all corners

  // of the processed triangle. For the best prediction, the UV coordinates

  // on the next/previous corners need to be already encoded/decoded.

  const CornerIndex next_corner_id =

      this->mesh_data().corner_table()->Next(corner_id);

  const CornerIndex prev_corner_id =

      this->mesh_data().corner_table()->Previous(corner_id);

  // Get the encoded data ids from the next and previous corners.

  // The data id is the encoding order of the UV coordinates.

  int next_data_id, prev_data_id;

  int next_vert_id, prev_vert_id;

  next_vert_id =

      this->mesh_data().corner_table()->Vertex(next_corner_id).value();

  prev_vert_id =

      this->mesh_data().corner_table()->Vertex(prev_corner_id).value();

  next_data_id = this->mesh_data().vertex_to_data_map()->at(next_vert_id);

  prev_data_id = this->mesh_data().vertex_to_data_map()->at(prev_vert_id);

  if (prev_data_id < data_id && next_data_id < data_id) {

    // Both other corners have available UV coordinates for prediction.

    const Vector2f n_uv = GetTexCoordForEntryId(next_data_id, data);

    const Vector2f p_uv = GetTexCoordForEntryId(prev_data_id, data);

    if (p_uv == n_uv) {

      // We cannot do a reliable prediction on degenerated UV triangles.

      // Technically floats > INT_MAX are undefined, but compilers will

      // convert those values to INT_MIN. We are being explicit here for asan.

      for (const int i : {0, 1}) {

        if (std::isnan(p_uv[i]) || static_cast<double>(p_uv[i]) > INT_MAX ||

            static_cast<double>(p_uv[i]) < INT_MIN) {

          predicted_value_[i] = INT_MIN;

        } else {

          predicted_value_[i] = static_cast<int>(p_uv[i]);

        }

      }

      return true;

    }

    // Get positions at all corners.

    const Vector3f tip_pos = GetPositionForEntryId(data_id);

    const Vector3f next_pos = GetPositionForEntryId(next_data_id);

    const Vector3f prev_pos = GetPositionForEntryId(prev_data_id);

    // Use the positions of the above triangle to predict the texture coordinate

    // on the tip corner C.

    // Convert the triangle into a new coordinate system defined by orthogonal

    // bases vectors S, T, where S is vector prev_pos - next_pos and T is an

    // perpendicular vector to S in the same plane as vector the

    // tip_pos - next_pos.

    // The transformed triangle in the new coordinate system is then going to

    // be represented as:

    //

    //        1 ^

    //          |

    //          |

    //          |   C

    //          |  /  \

    //          | /      \

    //          |/          \

    //          N--------------P

    //          0              1

    //

    // Where next_pos point (N) is at position (0, 0), prev_pos point (P) is

    // at (1, 0). Our goal is to compute the position of the tip_pos point (C)

    // in this new coordinate space (s, t).

    //

    const Vector3f pn = prev_pos - next_pos;

    const Vector3f cn = tip_pos - next_pos;

    const float pn_norm2_squared = pn.SquaredNorm();

    // Coordinate s of the tip corner C is simply the dot product of the

    // normalized vectors |pn| and |cn| (normalized by the length of |pn|).

    // Since both of these vectors are normalized, we don't need to perform the

    // normalization explicitly and instead we can just use the squared norm

    // of |pn| as a denominator of the resulting dot product of non normalized

    // vectors.

    float s, t;

    // |pn_norm2_squared| can be exactly 0 when the next_pos and prev_pos are

    // the same positions (e.g. because they were quantized to the same

    // location).

    if (version_ < DRACO_BITSTREAM_VERSION(1, 2) || pn_norm2_squared > 0) {

      s = pn.Dot(cn) / pn_norm2_squared;

      // To get the coordinate t, we can use formula:

      //      t = |C-N - (P-N) * s| / |P-N|

      // Do not use std::sqrt to avoid changes in the bitstream.

      t = sqrt((cn - pn * s).SquaredNorm() / pn_norm2_squared);

    } else {

      s = 0;

      t = 0;

    }

    // Now we need to transform the point (s, t) to the texture coordinate space

    // UV. We know the UV coordinates on points N and P (N_UV and P_UV). Lets

    // denote P_UV - N_UV = PN_UV. PN_UV is then 2 dimensional vector that can

    // be used to define transformation from the normalized coordinate system

    // to the texture coordinate system using a 3x3 affine matrix M:

    //

    //  M = | PN_UV[0]  -PN_UV[1]  N_UV[0] |

    //      | PN_UV[1]   PN_UV[0]  N_UV[1] |

    //      | 0          0         1       |

    //

    // The predicted point C_UV in the texture space is then equal to

    // C_UV = M * (s, t, 1). Because the triangle in UV space may be flipped

    // around the PN_UV axis, we also need to consider point C_UV' = M * (s, -t)

    // as the prediction.

    const Vector2f pn_uv = p_uv - n_uv;

    const float pnus = pn_uv[0] * s + n_uv[0];

    const float pnut = pn_uv[0] * t;

    const float pnvs = pn_uv[1] * s + n_uv[1];

    const float pnvt = pn_uv[1] * t;

    Vector2f predicted_uv;

    if (orientations_.empty()) {

      return false;

    }

    // When decoding the data, we already know which orientation to use.

    const bool orientation = orientations_.back();

    orientations_.pop_back();

    if (orientation) {

      predicted_uv = Vector2f(pnus - pnvt, pnvs + pnut);

    } else {

      predicted_uv = Vector2f(pnus + pnvt, pnvs - pnut);

    }

    if (std::is_integral<DataTypeT>::value) {

      // Round the predicted value for integer types.

      // Technically floats > INT_MAX are undefined, but compilers will

      // convert those values to INT_MIN. We are being explicit here for asan.

      const double u = floor(predicted_uv[0] + 0.5);

      if (std::isnan(u) || u > INT_MAX || u < INT_MIN) {

        predicted_value_[0] = INT_MIN;

      } else {

        predicted_value_[0] = static_cast<int>(u);

      }

      const double v = floor(predicted_uv[1] + 0.5);

      if (std::isnan(v) || v > INT_MAX || v < INT_MIN) {

        predicted_value_[1] = INT_MIN;

      } else {

        predicted_value_[1] = static_cast<int>(v);

      }

    } else {

      predicted_value_[0] = static_cast<int>(predicted_uv[0]);

      predicted_value_[1] = static_cast<int>(predicted_uv[1]);

    }

    return true;

  }

  // Else we don't have available textures on both corners. For such case we

  // can't use positions for predicting the uv value and we resort to delta

  // coding.

  int data_offset = 0;

  if (prev_data_id < data_id) {

    // Use the value on the previous corner as the prediction.

    data_offset = prev_data_id * num_components_;

  }

  if (next_data_id < data_id) {

    // Use the value on the next corner as the prediction.

    data_offset = next_data_id * num_components_;

  } else {

    // None of the other corners have a valid value. Use the last encoded value

    // as the prediction if possible.

    if (data_id > 0) {

      data_offset = (data_id - 1) * num_components_;

    } else {

      // We are encoding the first value. Predict 0.

      for (int i = 0; i < num_components_; ++i) {

        predicted_value_[i] = 0;

      }

      return true;

    }

  }

  for (int i = 0; i < num_components_; ++i) {

    predicted_value_[i] = data[data_offset + i];

  }

  return true;

}