Am 12.09.2018 um 23:43 schrieb Roland Scheidegger: > Am 12.09.2018 um 08:31 schrieb Axel Davy: >> On 9/12/18 8:17 AM, Axel Davy wrote: >>> >>> The goal is to catch inf and -inf and replace them by FLT_MAX and >>> -FLT_MAX. >>> >>> Without, the NaN would appear when doing mul or mad. > Ah I somehow completely missed this (but indeed this code will replace > nans with flt_max, I guess though it's fine as long as you try to avoid > getting nans as inputs there in the first place). > > >>> >>> Axel >>> >>> >>> >> I small precision I want to add: This is not the only place clamping >> makes a difference. >> >> Indeed else MUL_ZERO_WINS would be safe to use and remove all the clamping. >> >> >> The rasterizers can produce NaN when given Inf in the vertex shader on >> some devices for example, >> >> and I think on some devices inf and FLT_MAX give different color in the >> pixel shader. >> >> >> Thus why I want to test carefully what do the other vendors for all the >> shader versions (we know already there are >> >> behaviour changes for some) and check with the behaviours mentionned >> above, before removing the clamps when MUL_ZERO_WINS. > Yes it's all quite a mess. d3d9 rules are awkward (if they are even > documented), whereas gl may do whatever (personally I would consider at > least for core contexts everything not following ieee754 rules a bug, > well maybe not for gles...). Forgot to mention, of course unless forced with things like mul_zero_wins.
Roland > > Roland > > >> >> >> >> Axel >> > _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
