On Wed, 4 Dec 2002, Tino Schwarze wrote: > On Tue, Dec 03, 2002 at 06:39:16PM -0800, Jonathan Cohen wrote: > > > We are seriously considering ripping out all modes except for > > 32-bit floating point. This would drastically simplify the internal > > rendering engine and allow us to optimize it significantly. Since we > > don't see any real reasons why high-end paint work could not be done > > entirely in 32-bit float, this is a reasonable thing. > > I'm just curious: What do you get by using 32-bit _float_? Why not use > 1.31-Bit Fixed Point? It should have a higher precision than 32-bit > float - at least, it's precision is steady. For high dynamic range rendering. The sun is like a billion times brighter than a candle - and a candle is a thousand times brighter than the dimmest thing a human eye can see. Taking a 'true' rendition of the world needs more dynamic range than even a 32 bit integer. However, we don't need to measure the brightness of the sun to the precision of the dimmest thing we can see. So we DON'T need the precision of a 32 bit integer. Hence a 32 bit float is a more reasonable format. It's also the format that modern graphics cards are beginning to support (and will increasingly support in the future). ---- 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
