Method CreateTextureBuffer

Rendering/OpenGL2/vtkTextureObject.cxx:1079–1125

Description: Create a texture buffer basically a 1D texture that can be very large for passing data into the fragment shader

// Create a texture buffer basically a 1D texture that can be
// very large for passing data into the fragment shader
bool vtkTextureObject::CreateTextureBuffer(
  unsigned int numValues, int numComps, int dataType, vtkOpenGLBufferObject* bo)
{
  assert(this->Context);

  // Now, determine texture parameters using the arguments.
  this->GetDataType(dataType);
  this->GetInternalFormat(dataType, numComps, false);
  this->GetFormat(dataType, numComps, false);

  if (!this->InternalFormat || !this->Format || !this->Type)
  {
    vtkErrorMacro("Failed to determine texture parameters.");
    return false;
  }

  this->Target = GL_TEXTURE_BUFFER;
  this->Components = numComps;
  this->Width = numValues;
  this->Height = 1;
  this->Depth = 1;
  this->NumberOfDimensions = 1;
  this->BufferObject = bo;

  this->Context->ActivateTexture(this);
  this->CreateTexture();
  this->Bind();

  int maxSize = -1;
  this->Context->GetState()->vtkglGetIntegerv(GL_MAX_TEXTURE_BUFFER_SIZE, &maxSize);
  if (maxSize > 0 && static_cast<unsigned int>(maxSize) < numValues)
  {
    vtkErrorMacro("Attempt to use a texture buffer exceeding your hardware's limits. "
                  "This can happen when trying to color by cell data with a large dataset. "
                  "Hardware limit is "
      << maxSize << " values while " << numValues << " was requested.");
  }

  // Source texture data from the PBO.
  glTexBuffer(this->Target, this->InternalFormat, this->BufferObject->GetHandle());

  vtkOpenGLCheckErrorMacro("failed at glTexBuffer");

  this->Deactivate();

  return true;
}

#else