Z Pre-pass and PowerVR

Hidden surface removal on PowerVR hardware makes performing a Z pre-pass unnecessary

On PowerVR hardware there is no performance benefit to rendering a low-poly geometry Z pre-pass to save fragment processing later. Performing this operation would be a waste of clock cycles and memory bandwidth. The PowerVR hidden surface removal (HSR) hardware will detect and remove occluded (opaque) geometry from the pipeline automatically during rasterization, before fragment processing begins.