public bool UpdateAllRenderTargets()
{
// update all targets but don't swap buffers
this.activeRenderSystem.UpdateAllRenderTargets( false );
// give client app opportunity to use queued GPU time
bool ret = OnFrameRenderingQueued();
// block for final swap
this.activeRenderSystem.SwapAllRenderTargetBuffers( this.activeRenderSystem.WaitForVerticalBlank );
return ret;
}