Performance dies with added textures
WRVO (WRVO++at++chevron.com)
Wed, 29 Jul 1998 07:46:55 -0700
I have an application that renders a cube of data with textures - rather
simple. The textures are somewhat large in this case four of the faces
are 1k*2k and the other two are 2k*2k. They are luminance in byte
format. The amount of texture memory needed to hold these textures is
then (4*1k*2k + 2*2k*2k)*4 [the final 4 is because they are stored at
32bit textures]. This is then 8k*2k*4 or 64k of memory or 100% of the
texture memory on my Onyx2. If I change the geometry by cutting a corner
out of the cube, I add three more textures. This doesn't have any effect
on the performance. I can cut another corner out and still have no
effect. So now I am using 200% of texture memory and haven't had any
effect on performance. Now if I cut another corner out I have a total of
15 textures using a total of 64k+64k+32k of tram. Now the performance
drops from 36 fps to 1 fps. The gfx stats now indicates that I'm
downloading 7 textures at some rate of 83000. Performance stinks.
What is happening and is there anything I can do about it?
Thanks,
Bill Volz - Senior Research Geophysicist
Chevron Petroleum Technology
Voice: (281)-596-2059 Fax: (281)-493-7088
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on Mon Aug 10 1998 - 17:57:45 PDT