Method ExtractPrimitiveAccessorData

IO/Geometry/vtkGLTFDocumentLoader.cxx:596–677

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//------------------------------------------------------------------------------
bool vtkGLTFDocumentLoader::ExtractPrimitiveAccessorData(Primitive& primitive)
{
  // Load connectivity
  if (primitive.IndicesId >= 0)
  {
    // Load indices
    if (primitive.IndicesId >= static_cast<int>(this->InternalModel->Accessors.size()))
    {
      vtkErrorMacro("Invalid indices id for primitive");
      return false;
    }
    auto accessor = this->InternalModel->Accessors[primitive.IndicesId];
    auto bufferView = this->InternalModel->BufferViews[accessor.BufferView];

    if (accessor.Type != AccessorType::SCALAR)
    {
      vtkErrorMacro(
        "Invalid accessor.type value for primitive connectivity loading. Expected 'SCALAR'");
      return false;
    }
    auto& buffer = this->InternalModel->Buffers[bufferView.Buffer];

    primitive.Indices = vtkSmartPointer<vtkCellArray>::New();
    unsigned int byteOffset = accessor.ByteOffset + bufferView.ByteOffset;

    switch (accessor.ComponentTypeValue)
    {
      case ComponentType::UNSIGNED_BYTE:
        ExtractAndCastCellBufferData<uint8_t>(buffer, primitive.Indices, byteOffset,
          bufferView.ByteStride, accessor.Count, primitive.CellSize, primitive.Mode);
        break;
      case ComponentType::UNSIGNED_SHORT:
        ExtractAndCastCellBufferData<uint16_t>(buffer, primitive.Indices, byteOffset,
          bufferView.ByteStride, accessor.Count, primitive.CellSize, primitive.Mode);
        break;
      case ComponentType::UNSIGNED_INT:
        ExtractAndCastCellBufferData<uint32_t>(buffer, primitive.Indices, byteOffset,
          bufferView.ByteStride, accessor.Count, primitive.CellSize, primitive.Mode);
        break;
      default:
        vtkErrorMacro("Invalid accessor.componentType for primitive connectivity. Expected either "
                      "GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT or GL_UNSIGNED_INT.");
        return false;
    }
  }
  else
  {
    primitive.Indices = nullptr;
  }

  if (!this->ExtractPrimitiveAttributes(primitive))
  {
    vtkErrorMacro("Error loading mesh.primitive.attributes");
    return false;
  }
  if ((primitive.Indices != nullptr) && (!primitive.AttributeValues.empty()))
  {
    /* Get the elements count of the first associated accessor */