virtual void waiting_for_answer()
Requests the graphics engine to expedite the pending answer–the application is now waiting until the...
virtual int get_num_fragments() const =0
Returns the number of fragments (pixels) of the specified geometry that passed the depth test...
virtual bool is_answer_ready() const =0
Returns true if the query's answer is ready, false otherwise.
Returned from a GSG in response to begin_occlusion_query() .