Re: Infinite Reality, Colour matrix and pfTexEnv Component

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Ran Yakir (rany++at++rtset.co.il)
Tue, 21 Jan 1997 08:35:02 -0800

>
> 1) More an OpenGL question than a specific Performer question:
> The glTexImage2D manual page states that RE, RE2 and VTX graphics
> systems do not support colour matrix transformations as textures are
> loaded or read back from texture memory. Does this apply to
> InfiniteReality graphics as well? I think so, but then I may just be
> doing something wrong.

Color matrix (and also colour matrix) can be applied to texture loads on
InfiniteReality, Impact and O2. On RE, RE2 and VTX it is applied only to pixel
transfers (glCopyPixels, glDrawPixels).

>
> 2) Performer question - the pfTexEnv::setComponent call allows one
> component of an RGBA texture to be selected and used as a single
> component intensity texture. The manual says that a 16 bit RGBA texture
> could be used to provide 4 independent 4-bit intensity textures - I
> presume this is just an example, am I correct? I want to use a 32bit
> RGBA texture as separate 8 bit intensity textures as an alternative to
> the colour matrix transformation.

The setComponent call is valid only in IrisGL on RE2. On all OpenGL machines,
interleaved textures are supported through the GL_DUAL_TEXTURE and
GL_QUAD_TEXTURE parameters in OpenGL, and not through the texture environment.

Ran

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