Method Load

Rendering/OpenGL2/vtkPBRLUTTexture.cxx:30–179

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
void vtkPBRLUTTexture::Load(vtkRenderer* ren)
{
  vtkOpenGLRenderWindow* renWin = vtkOpenGLRenderWindow::SafeDownCast(ren->GetRenderWindow());
  if (!renWin)
  {
    vtkErrorMacro("No render window.");
    return;
  }

  if (this->GetMTime() > this->LoadTime.GetMTime())
  {
    if (this->TextureObject == nullptr)
    {
      this->TextureObject = vtkTextureObject::New();
    }
    this->TextureObject->SetContext(renWin);
    this->TextureObject->SetFormat(GL_RG);
    this->TextureObject->SetWrapS(vtkTextureObject::ClampToEdge);
    this->TextureObject->SetWrapT(vtkTextureObject::ClampToEdge);
    this->TextureObject->SetMinificationFilter(vtkTextureObject::Linear);
    this->TextureObject->SetMagnificationFilter(vtkTextureObject::Linear);
#ifdef GL_ES_VERSION_3_0
    this->TextureObject->SetInternalFormat(GL_RG8);
    this->TextureObject->SetDataType(GL_UNSIGNED_BYTE);
    this->TextureObject->Allocate2D(this->LUTSize, this->LUTSize, 2, VTK_UNSIGNED_CHAR);
#else
    this->TextureObject->SetInternalFormat(GL_RG16);
    this->TextureObject->SetDataType(GL_UNSIGNED_SHORT);
    this->TextureObject->Allocate2D(this->LUTSize, this->LUTSize, 2, VTK_UNSIGNED_SHORT);
#endif

    this->RenderWindow = renWin;

    vtkOpenGLState* state = renWin->GetState();
    vtkOpenGLState::ScopedglViewport svp(state);
    vtkOpenGLState::ScopedglEnableDisable sdepth(state, GL_DEPTH_TEST);
    vtkOpenGLState::ScopedglEnableDisable sblend(state, GL_BLEND);
    vtkOpenGLState::ScopedglEnableDisable sscissor(state, GL_SCISSOR_TEST);

    vtkNew<vtkOpenGLFramebufferObject> fbo;
    fbo->SetContext(renWin);
    renWin->GetState()->PushFramebufferBindings();
    fbo->Bind();

    fbo->AddColorAttachment(0, this->TextureObject);
    fbo->ActivateDrawBuffers(1);
    fbo->Start(this->LUTSize, this->LUTSize);

    std::string FSSource = vtkOpenGLRenderUtilities::GetFullScreenQuadFragmentShaderTemplate();

    vtkShaderProgram::Substitute(FSSource, "//VTK::FSQ::Decl",
      "const float PI = 3.14159265359;\n"
      "float RadicalInverse_VdC(uint bits)\n"
      "{\n"
      "  bits = (bits << 16u) | (bits >> 16u);\n"
      "  bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);\n"
      "  bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);\n"
      "  bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);\n"