Method GetNeedToRebuildBufferObjects

Rendering/OpenGL2/vtkOpenGLPolyDataMapper.cxx:3770–3795

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//------------------------------------------------------------------------------
bool vtkOpenGLPolyDataMapper::GetNeedToRebuildBufferObjects(
  vtkRenderer* vtkNotUsed(ren), vtkActor* act)
{
  // we use a state vector instead of just mtime because
  // we do not want to check the actor's mtime.  Actor
  // changes mtime every time it's position changes. But
  // changing an actor's position does not require us to
  // rebuild all the VBO/IBOs. So we only watch the mtime
  // of the property/texture. But if someone changes the
  // Property on an actor the mtime may actually go down
  // because the new property has an older mtime. So
  // we watch the actual mtime, to see if it changes as
  // opposed to just checking if it is greater.
  this->TempState.Clear();
  this->TempState.Append(act->GetProperty()->GetMTime(), "actor mtime");
  this->TempState.Append(this->CurrentInput ? this->CurrentInput->GetMTime() : 0, "input mtime");
  this->TempState.Append(act->GetTexture() ? act->GetTexture()->GetMTime() : 0, "texture mtime");

  if (this->VBOBuildState != this->TempState || this->VBOBuildTime < this->GetMTime())
  {
    this->VBOBuildState = this->TempState;
    return true;
  }

  return false;
}

//------------------------------------------------------------------------------
// create the cell scalar array adjusted for ogl Cells