Method BuildShader

Rendering/VolumeOpenGL2/vtkOpenGLGPUVolumeRayCastMapper.cxx:2810–2869

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

//------------------------------------------------------------------------------
void vtkOpenGLGPUVolumeRayCastMapper::BuildShader(vtkRenderer* ren)
{
  std::map<vtkShader::Type, vtkShader*> shaders;
  vtkShader* vertexShader = vtkShader::New();
  vertexShader->SetType(vtkShader::Vertex);
  shaders[vtkShader::Vertex] = vertexShader;
  vtkShader* fragmentShader = vtkShader::New();
  fragmentShader->SetType(vtkShader::Fragment);
  shaders[vtkShader::Fragment] = fragmentShader;
  vtkShader* geometryShader = vtkShader::New();
  geometryShader->SetType(vtkShader::Geometry);
  shaders[vtkShader::Geometry] = geometryShader;

  auto vol = this->Impl->GetActiveVolume();

  vtkOpenGLShaderProperty* sp = vtkOpenGLShaderProperty::SafeDownCast(vol->GetShaderProperty());
  this->GetShaderTemplate(shaders, sp);

  // user specified pre replacements
  vtkOpenGLShaderProperty::ReplacementMap repMap = sp->GetAllShaderReplacements();
  for (const auto& i : repMap)
  {
    if (i.first.ReplaceFirst)
    {
      std::string ssrc = shaders[i.first.ShaderType]->GetSource();
      vtkShaderProgram::Substitute(
        ssrc, i.first.OriginalValue, i.second.Replacement, i.second.ReplaceAll);
      shaders[i.first.ShaderType]->SetSource(ssrc);
    }
  }

  auto numComp = this->AssembledInputs[0].Texture->GetLoadedScalars()->GetNumberOfComponents();
  this->ReplaceShaderValues(shaders, ren, vol, numComp);

  // user specified post replacements
  for (const auto& i : repMap)
  {
    if (!i.first.ReplaceFirst)
    {
      std::string ssrc = shaders[i.first.ShaderType]->GetSource();
      vtkShaderProgram::Substitute(
        ssrc, i.first.OriginalValue, i.second.Replacement, i.second.ReplaceAll);
      shaders[i.first.ShaderType]->SetSource(ssrc);
    }
  }

  // Now compile the shader
  //--------------------------------------------------------------------------
  this->Impl->ShaderProgram = this->Impl->ShaderCache->ReadyShaderProgram(shaders);
  if (!this->Impl->ShaderProgram || !this->Impl->ShaderProgram->GetCompiled())
  {
    vtkErrorMacro("Shader failed to compile");
  }

  vertexShader->Delete();
  fragmentShader->Delete();
  geometryShader->Delete();