On Tuesday 08 February 2005 22:06, Daniel Phillips wrote: > > It's the interpolants that are really going to eat multipliers: > > Horizontal rasterization: > > - two multiplies per interpolant for perspective correction > > Vertical rasterization: > > - one multiply per interpolant to correct for pixel alignment
Are these in the model yet? > With 17 interpolants, most of which need perspective correction (in my > opinion; some may think this justifiable only for textures) we've > already exceeded our multiplier budget and haven't even begun to think > about filtering, blending, mipmapping, fog and probably other things. If we can make a reciprocal with a LUT and some logic, maybe we can do the same for a multiplier? Haven't thought it through, but multiplying is generally easier than dividing. > So pretty soon it's time to make some hard choices about what is > expendable, where to compromise on quality and throughput, and how > throughput is going to degrade gracefully as features are turned on. > All of which I'm sure Timothy has been thinking about, but now it's > about time to take inventory and see just how bad things are. How complete is the software model right now? I think it would be a good idea to try and complete that as much as possible. It will give a complete picture of what we need to do, and a framework to figure out what is the best compromise. > It's also possible to create more multipliers in random logic, as > Timothy mentioned several times, but this is only going to work out in > places where precision is really limited. And it may be expensive. If a single generic adder takes up 1%, then how much will a multiplier be? Lourens _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
