On Mon, Dec 21, 2009 at 10:49:14AM -0700, tom fogal wrote: | ... GL really | needs a query that allows an application developer to figure out if a | feature is accelerated by the hardware or not. Since it lacks this, | the advertising of extensions is just about the only thing we, as app | developers, can use as a heuristic.
This has been discussed since the Dawn of Time, but it might be useful to recap the main reasons why such a query doesn't exist: (1) There's no tractable way to enumerate isolated features or deal with the combinatorial explosion of state variables that affect whether any given feature is accelerated. (2) Some features can be partially accelerated, so it's not clear what a query should return in such cases. (3) On some systems, there have been features that were available in the GPU but were faster if implemented in software on the CPU. (4) Even if a feature is "accelerated" in some way, it may still be too slow to use. The only reliable way to solve the problem is to benchmark the operations you want to use, in precisely the conditions you intend to use them, and then make a judgement as to whether the performance is good enough. This tends to be application-specific, so previous attempts to make a centralized database of results failed. I wouldn't say it's impossible, but it is very difficult. I haven't tracked this subject since I left the ARB, but maybe the Khronos folks have done some more work on it. As you say, using extension advertisements seems to be the most common workaround, though it's far from perfect. Allen ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
