Ian Romanick wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Dave Airlie wrote: > >> Hey, >> >> So I've been playing with radeon FBOs and have run into a problem with how >> to allow apps to get an FBOs that isn't swrast fallback :-) >> >> radeons can by default render to ARGB8888, ARGB4444, RGB565 mostly, now in >> this case when the app asks for a texture format of GL_RGBA, >> GL_UNSIGNED_BYTE, we return by default a texture format, of >> &_mesa_texformat_rgba8888_rev >> >> This allows us to do memcpy texture uploads in theory, however >> when it comes time to render to that texture, I have to go hit a sw >> fallback which sucks badly. >> >> I see my options as >> a) apps are smart, ignore problem and move on. >> b) pick FBO friendly texture formats by default at the expense of textures >> c) magically change the texture format when I realise something is >> rendering to it (is this possible any ideas?) >> d) at least for r300, hack up the fragment shader to swizzle the outputs >> though I think for dest blending this might not work like I think it >> would. >> >> hopes nobody tells me the FBO spec covers this and I'm lazy :) >> > > The intention when we wrote the FBO spec is that drivers would do either > B or C. In the typical usage an application won't supply a texture with > data and render to it. Apps will usually do one or the other. Since > you should be able to quickly reformat the component order of a buffer > once it's already in card memory, C is probably the best performance > choice. However, B is a lot less code to write. > > As you point out, D won't work. As for A...seriously? :) > One should point out, though, that B) makes the same assumptions for apps with a lot of texture downloads, as A) does for apps using fbos, although the outcome if you supply a bad format usually isn't that catastrophical...
/Thomas > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.9 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org > > iEUEARECAAYFAknJVbAACgkQX1gOwKyEAw+vJQCY5weCuqx9SwsAEhajohFGxeOb > 9wCfZSJ7J9nfliZQaKQjm0fM5lXeCIE= > =5diw > -----END PGP SIGNATURE----- > > ------------------------------------------------------------------------------ > Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are > powering Web 2.0 with engaging, cross-platform capabilities. Quickly and > easily build your RIAs with Flex Builder, the Eclipse(TM)based development > software that enables intelligent coding and step-through debugging. > Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com > _______________________________________________ > Mesa3d-dev mailing list > Mesa3d-dev@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mesa3d-dev > ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
