Jerome Glisse wrote: > On 2/14/07, Rune Petersen <[EMAIL PROTECTED]> wrote: >> Roland Scheidegger wrote: >>> Roland Scheidegger wrote: >>>>>> Rune Petersen >>>>>> >>>>> Ok commited. >>>> I didn't look too closely at this but I've a couple of comments. >>>> - COS looks too complicated & broken. If you'd want to get 2 with a >>>> LOG2, you'd need 0.25 as source. But even using RCP instead, that's 5 >>>> instructions before performing the sine, for something you can easily do >>>> in two, using another constant (just 1 add + 1 cmp needed, if you use >>>> the right constants for the add). Maybe it's not that bad though, I >>>> don't know how many rgb and a slots it will actually consume, but still, >>>> are constant slots that rare? >>>> Second, you'd really need to do range reduction of the input, otherwise >>>> results will be very wrong for inputs outside [-pi, pi]. This would be >>>> true for taylor approximation too, of course, unless you do an infinite >>>> series :-). You wouldn't need to do that for SCS. >>> Oh, and forgot to mention, you probably really want to use the higher >>> precision variant by default. 12% max relative error (and even absolute >>> it's still 6%) will likely be visible in some cases depending what the >>> shader is doing. Even the enhanced version seems to miss opengl >>> conformance (accurate to "about 1 part in 10^5") by roughly a factor of >>> 10, which stretches the meaning of "about" a bit probably already. >>> You could also rely on the precision hint for fragment programs to >>> switch to the faster version instead of a dri conf option (note though >>> the spec explicitly states implementations are discouraged even in this >>> case to perform optimizations which could have significant impact on the >>> output). >>> >> This patch: >> - Fixes COS. >> - Does range reductions for SIN & COS. >> - Adds SCS. >> - removes the optimized version of SIN & COS. >> - tweaked weight (should help on precision). >> - fixed a copy paste typo in emit_arith(). >> >> Roland would you mind testing if the tweaked weight helped? >> >> And Jerome would you mind committing this? >> >> >> Rune Petersen >> > > Pushed, git isn't so frightening trust me :) > I'll make you a promise: after March 1. I'll commit my own patches.. until than I can't really get a handle on it (too much on my mind).
Rune Petersen ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
