* Multi-threading note: this method should be called from a dedicated rendering thread.
* @pre The GL context must have been created, and made current.
* @param[out] status showing whether update is required to run.
+ * @param[in] forceClear force the Clear on the framebuffer even if nothing is rendered.
*/
- void Render( RenderStatus& status );
+ void Render( RenderStatus& status, bool forceClear );
// System-level overlay