On Sat, 2 Nov 2002, Marc wrote: > On Sat, Nov 02, 2002 at 08:16:37AM +0000, Nick Lamb <njl98r@xxxxxxxxxxxxxxx> wrote: > > This probably ought to be on our horizon too. Modern FPUs are very fast > > and RAM gets ever cheaper. > > And caches get slower... and RAM is _slow_. > > I don't say not to also support float, I just wanted to point out that > performance is very much dependent on cache optimizations, as every > fortran programmer knows ;) It might be interesting to consider doing some of the work of compositing in the graphics card - where the hardware supports it. The latest generations of nVidia and ATI cards have support for full floating point pixel operations and floating point frame buffers. If you stored each layer as a texture and wrote a 'fragment shader' to implement the GIMP's layer combiners, you'd have something that would be *FAR* faster than anything you could do in the CPU. Of course only people with sexy new graphics cards would reap the benefits - but I presume that people who care enough to want high precision pixels are probably professionals to whom a $500 graphics card wouldn't be an obstacle if it helped their work. Going to full floating point per colour component would conclusively remove any issues of precision through any reasonable number of layering operations. > I think that we very well can display 16 bits or higher, after all, we can > have 16 bit linear and output 8 bit gamma-corrected. That's certainly true - and there are graphics cards out there that can do 10 bits per component per pixel. ---- Steve Baker (817)619-2657 (Vox/Vox-Mail) L3Com/Link Simulation & Training (817)619-2466 (Fax) Work: sjbaker@xxxxxxxx http://www.link.com Home: sjbaker1@xxxxxxxxxxx http://www.sjbaker.org
