Method DrawInstancedElementsImpl

Rendering/OpenGL2/vtkDrawTexturedElements.cxx:438–509

}

void vtkDrawTexturedElements::DrawInstancedElementsImpl(
  vtkRenderer* ren, vtkActor*, vtkMapper* mapper)
{
  if (this->ShaderProgram == nullptr)
  {
    // can be nullptr if glsl failed to compile or link
    return;
  }

  // Determine number of invocations of the vertex shader.
  this->P->Count = static_cast<GLsizei>(this->NumberOfElements);
  switch (this->ElementType)
  {
    case vtkDrawTexturedElements::ElementShape::Point:
      break;
    case vtkDrawTexturedElements::ElementShape::Line:
      this->P->Count *= 2;
      break;
    case vtkDrawTexturedElements::ElementShape::LineStrip:
      ++this->P->Count;
      break;
    case vtkDrawTexturedElements::ElementShape::Triangle:
      this->P->Count *= 3;
      break;
    case vtkDrawTexturedElements::ElementShape::TriangleStrip:
      this->P->Count += 2;
      break;
    case vtkDrawTexturedElements::ElementShape::TriangleFan:
      this->P->Count += 2;
      break;
    case vtkDrawTexturedElements::ElementShape::AbstractPatches:
#ifdef GL_ARB_tessellation_shader
    {
      (void)mapper;
      const int patchVertexCount = this->PatchVertexCountFromPrimitive(this->PatchType);
      this->P->Count *= patchVertexCount;
      glPatchParameteri(GL_PATCH_VERTICES, patchVertexCount);
      break;
    }
#else
      vtkErrorWithObjectMacro(mapper, << "ElementType cannot be \'AbstractPatches\' because "
                                         "GL_PATCHES is not supported in this build of VTK.");
      break;
#endif
    default:
    {
      vtkGenericWarningMacro("Invalid element type " << this->ElementType << ".");
      break;
    }
  }
  auto instances = static_cast<GLsizei>(this->NumberOfInstances);
  vtkOpenGLStaticCheckErrorMacro("Just before draw instanced");
  // Render the element instances:
#ifdef GL_ES_VERSION_3_0
  (void)ren;
  glDrawArraysInstanced(this->P->Primitive, this->FirstVertexId, this->P->Count, instances);
#else
  if (GLAD_GL_VERSION_3_1)