[oshepherd]

> Not all GPUs have the Z-Buffer fillrate to make that approach viable(esp on mobile). I've seen more than a few cases where it was actually faster to turn off Z-Buffering and do the overdraw. More than a few architectures share Z-Buffer bandwidth with other pipelines.

Uh, mobile GPUs tend to be way, way ahead of desktop GPUs in Z-Buffer bandwidth (especially in relative terms)

and you can't increase your tile count; there's a fixed number of tiles in the frame buffer (unless you're referring to not drawing some tiles at all - in which case set your scissor rect appropriately. oh, and if you can find out the GPU's tile size round your rectangle up to cover whole tiles)

[vvanders]

Not quite, tile based GPUs tend to be better on Z-Buffer bandwidth but not all mobile GPUs are true tile-based GPUs.

The number of tiles can definitely change, it's something Qualcomm calls out directly in one of their talks[1]. As your tile count increases so does your setup cost for your drawcalls.

[1] https://youtu.be/SeySx0TkluE?t=41