Re: How could I use 24-bit texels texture?

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Rémi Arnaud (remi++at++remi.asd.sgi.com)
Wed, 26 Mar 1997 11:45:20 -0800 (PST)

pere1++at++cluny.ensam.fr wrote:
>
> Hello,
>
> I have a problem with pfTexFormat. I would like to use 24-bit texture
> in a special application. In pfTexture reference pages, I saw that the default
> 4 component internal format is 16-bit texels (PFTEX_RGB_5), I tried
> PFTEX_RGBA_8 to set the format to 32-bit texels. This works well but because it
> seems too simple, my texture is 2048x2048.
>
> Image size (SxTxR) = 2048x2048x1
> PF Download size = 22369626 bytes
> PF Download time =3759.588 ms
> PF Download rate = 5.674 MB/sec
> PF Total texture use = 21.333 MB
> PF This texture uses = 533.333% of 4MB memory
> PF Total texture use = 533.333% of 4MB memory
>
>
> The hardware texture memory is saturated. But Performer swaps with the main
> memory and the image is here at slowly rate but I don't need real time for this
> application ( In fact, I want to render 2Dimensional frames faster than
> with Wavefront software). Well, it seems good except that the mapping texture
> is not at the right size (2048x2048),it is pixelated. Does it mean that
> Performer uses a low level of mipmap texture because the hardware texture
> memory is out?

 No, performer do not make any difference if you use less or more than 100%
 of the texture memory, only the frame rate will be (a lot) different.

 If the problem is mipmapping, the the image should be fuzzy, not pixelated.
 Anyway, do you need mipmapping in your application ?

 Try with a 6x smaller pixture by taking part of your image, not filtering
 it, and see if you have the same problem.

 J'espere vous avoir aide, bon courage.

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