Re: Tlut performance

New Message Reply Date view Thread view Subject view Author view

ledogar++at++flanders.mtv.gtegsc.com
Wed, 19 Jul 95 17:07:07 -0700

We are using dynamic textures with subtexload, with TX_IA_8 as the internal
format (although we're only storing intensity). We have a 4-component lookup
table, so I looks up ABGR. We only use that table for one geode in our scene,
so we call tlutbind twice per frame.

If the lookup is applied to the image data as it goes _into_ texmem, I can't see
how all four components would fit into our 16-bits-per-texel texture-memory
region. So I think the texture lookup is done for each texel as it comes _out_
of texture memory, and before it goes through the texture environment function.

As far as I can tell, these calls have no effect on performance, and the
textures on the other geodes come through normally.

I guess that means the tluts are loaded into some hardware registers somewhere
(for speed)... I wonder what the limit is on the size/number of tluts?

Disclaimer: our code isn't totally debugged yet, so my results might be
accidental...

--- Charlie Ledogar
GTE Government Systems
Mountain View, CA

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:51:41 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.