Gamedev forum software broke again - cannot use any formatting.
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joew: "discard is actually destructive on nearly all current mobile chips and should be avoided at all costs, especially if you are targetting mobile devices that are a few years old. There is always a better way (performance-wise) even if some are slight asset hacks. Also null blends are vastly cheaper than using discard at least on PVR chips."
Thanks for actually addressing the question. Just to clarify, did you mean that "null blends are vastly cheaper than using discard when depth (and stencil) testing is disabled"? As thous would obviously be hurt quite badly by discard.
swiftcoder: "You are missing the point of my post: there are many methods to reject pixels, and there is no magic bullet.
Asking whether discard degrades performance is a subjective question. What are we comparing it to? The performance of not discarding pixels? The performance of using another pixel rejection path?"
If you would have read my relevant post then you would have known exactly what the question was meant to compare - and hence know that you do not HAVE a point. _Not relevant to the question anyway_.
To recap for your benefit (post #26 onwards): "It might be worth using discard after doing everything else (geometry approximation in particular) given that depth test is unusable. Hm, not sure how much of an impact discard has under thous circumstances - reading around about mobile devices did not clear the question, does anyone know?"