On 09-Dec-2002, Stephen J Baker wrote: > 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). First, maybe can you guys _slow down?_ I can only respond so fast =) Seriously though, yeah, 32-bit floats do dynamic range so much better (and with the way I abuse Gimp, I need the dynamic range.) But (as I've said about four times already) the speed boost on archs that can do spfp math (aka sse enabled archs) is more than worth it. -- Patrick "Diablo-D3" McFarland || unknown@xxxxxxxxx "Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." --Kristian Wilson, Nintendo, Inc, 1989
Attachment:
pgpQd1riuRI5d.pgp
Description: PGP signature
