Hi, On Mon, Feb 23, 2009 at 7:32 AM, Robert Bragg <[email protected]> wrote: > The biggest disadvantage to dealing with the matrices client side looks > to be with tracking the inverse matrix. Calculating the inverse can be a > rather expensive operation, and at least looking at the Mesa code it's > clear they have quite a bit of smarts involving tagging matrices > according to the transformations they represent to allow selecting the > most optimal inverse calculation function. (E.g. think of cases like > glTranslatef (x,y,z), the inverse is dead simple.)
To be sure I'm understanding correctly, you are saying that if we always send GL a LoadMatrix instead of say Translate, then the mesa code has to "analyze from scratch" to get the inverse and other properties, while if we send Translate it knows a lot to start with? (Somewhat frustratingly, because my patch just has the Mesa code in it, so we have exactly what Mesa computes already on cogl side!) I mentioned a theory like this last night on the bug; it's probably pretty easy to send Mesa a Translate instead of a LoadMatrix for example at least for many common cases. Havoc -- To unsubscribe send a mail to [email protected]
