On Thu, Oct 17, 2002 at 09:22:37AM -0700, Ian Romanick wrote: | ... | So, I asked a couple people around IBM what the accepted practice was. I | was told that an implementation is not required to export extension strings | for extensions that are required for its adverteised OpenGL version. I was | then told about Nvidia's technique.
It's true that you don't have to advertise extensions that match the functionality in your version of the core. However, if you supported an extension in the past, you're likely to break a bunch of apps if you *stop* supporting it in a new release. Also, I wouldn't want to encourage app developers to use the absence of an extension string to determine whether a core function is hardware accelerated. There are plenty of corner cases now (Brian mentioned one), and as programmability becomes more widely available, there are about to be a *lot* more. (For example, some machines have native high-precision exponentiation and logarithm. Others don't, and have to emulate them with an instruction sequence that's roughly an order of magnitude slower and requires extra registers. The host CPU might be faster if a vertex program is heavily loaded with such instructions. Is "hardware accelerated" meaningful in cases like this?) During the long debate over ARB_vertex_program, the ARB reached the consensus that we need to address the "is it fast" question directly. So in the meantime I wouldn't want to tell people to infer performance parameters by using mechanisms that weren't designed for that purpose. Allen ------------------------------------------------------- This sf.net email is sponsored by: viaVerio will pay you up to $1,000 for every account that you consolidate with us. http://ad.doubleclick.net/clk;4749864;7604308;v? http://www.viaverio.com/consolidator/osdn.cfm _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
