Roland Scheidegger wrote: > Brian Paul wrote: > >> Matthias Hopf wrote: >> >>> On Jun 23, 06 19:59:58 +0100, Keith Whitwell wrote: >>> >>>>> The egg on our face is that, AFAIK, Mesa based drivers are the *only* >>>>> drivers that don't support this functionality. That app developers >>>>> expect it to be there isn't surprising. >>>> >>>> I guess I was the one who introduced the behaviour in the first >>>> place. While it does make the driver pass a few conformance tests, >>>> in general nobody likes the behaviour... I think we'd be better off >>>> with a not-fully-conformant wide point emulation, ideally one >>>> abstracted slightly above the driver level, so that at least we're >>>> making an attempt to do the expected thing. >>> >>> >>> Thinking about that, does Mesa support point sprites at all? If it does >>> (with point sizes > 1, otherwise it doesn't make sense), you can emulate >>> antialiased points by loading an antialiased filled circle into a >>> GL_ALPHA >>> texture and using this texture for point sprites. >> >> >> Core Mesa supports points sprites of arbitrary size. >> >> It seems like it shouldn't be hard to write a re-usable driver routine >> to generate textured quads to render large/smoothed/sprite points in >> the hardware drivers. > > I still can't quite see how you'd do that so it works no matter what > alpha blend function is used (unless you have hw which supports texkill, > which r300 for instance doesn't even support natively). And, for drivers > which support hw tcl, you probably have to fall back to sw tcl or do > some other hacks.
Are you concerned about emitting fragments outside the radius of the large/smooth point? I think we could use the alpha test to cull them. There may be some cases that can't be easily handled (like textured points with a particular texenv/blend mode) where the fragment alpha at the end can't be used for culling. But I think the common cases for large/smooth point rendering could be handled. You're right about the sw tcl fallback. But I think the loss due to software tcl wouldn't be nearly as bad as the penalty for sw rasterization of large/smooth points. -Brian Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Mesa3d-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
