From: Angus Dorbie (dorbie++at++sgi.com)
Date: 11/07/2000 17:19:02
Depends on the internal format and the platform and MIP mapping.
This question has come up in the past and is covered in the archives.
but the internal format might use 2 bytes instead of 4 per texel for an
RGBA by default in Performer,, in addition a platform like iR has a
texture memory word size of 2 bytes so a single component texture will
take a minimum of 2 bytes. MIP mapping will always cost about an
additional third of the texture memory based on image size calculation.
Cheers,ANgus.
christopher.g.dorosky++at++lmco.com wrote:
>
> I am confused about how to do a simple texture memory calculation.
>
> If I have a 1024 * 1024 texture, that is rgba, and I load it in, how much texture memory does it use?
>
> I would guess 1024*1024*4 = 4 Megabytes.
>
> If it is simply an intensity map, does it take 1 or two megs? I have been told that performer stores the textures internally as 16 bit, so a 8 bit 1024*1024 intensity map really takes 2Meg.
>
> Could somebody please clarify how do do the calculation for monochrome, rgb and rgba?
>
> Thanks.
>
> Christopher Dorosky
> Lead Electronic Systems Engineer - Real Time Simulation
> Lockheed Martin Missiles and Fire Control - Dallas
> christopher.g.dorosky++at++lmco.com
> 972-603-2349
>
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