Ian Romanick wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Brian Paul wrote: > >> Another thought is to move some traditional per-fragment operations into >> the fragment program itself. Alpha test, for example, may no longer >> exist in OpenGL 3.0; it would be up to the user to encode the test in >> their shader. >> >> With software rendering, we have the potential to do almost everything >> in the fragment shader. One idea I had is to add a new input register >> to fragment programs which is the current framebuffer color. We could >> use that to do blending/masking/etc. in the program. Normally, this >> would be hidden, but it could be exposed as an interesting new OpenGL >> extension (and something unique to Mesa). > > The other option is to add another shader stage for post-fragment > operations. This is roughly analogous to how geometry shaders are > implemented. When I've thought about this in the past, I had only > considered using it to replace alpha blending and stencil operations. > > I don't see any reason why we couldn't also implement alpha and stencil > testing in the same stage. I'm a bit nervous about including depth > testing. It seems like that would cause issues with early Z test.
You could do early stencil testing just as well (there is hardware out there AFAIK which supports that). Roland ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Mesa3d-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
