On Mon, 2009-11-23 at 17:28 -0800, Brian Paul wrote: > For OpenGL, the front-facing attribute is either 0 (back) or 1 (front) rather > than +/-1. > > I think we'll need to do some additional work (insert a MAD instr?) in the > Mesa->TGSI translation to account for this difference. I could dig into that > someday...
I'm assuming DX or some other API uses +/-1? If we define tgsi to use +/-1, then the GL 0/1 version can be reached by just saturating. Getting from 0/1 to +/-1 looks like it would be a MAD as you say. Probably +/-1 is easy to calculate as the sign of the determinant, which would be an intermediate step to calculate GL's version. If it's OK, let's define TGSI's face reg as +/-1, and have Mesa insert the saturate if necessary. Keith ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Mesa3d-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
