Texture Compression and byte sized verts

Hi all,
This is more of a standards question than a how-to question. Can I assume that texture compression and byte sized vertices are supported by all OpenGL ES implementations?
I’m a little confused by the different types of extension flavours (ARB/EXT/ES specific / Core). I’d appretiate some clarification as I’m working on mobile devices that would really benefit from textures compression / byte verts to save memory. It would be nice if I could assume they have both features.

Thanks,

Steve.

Hi Steven.

Yes, byte vertices and texture compression are mandatory features for any OpenGL ES 1.0 conformant implementation. The only mandated texture compression format though is paletted texture format (4-bit and 8-bit indices).

–jani;

Fantastic, that’s made my life a whole of easier, thanks Jani.

Has anyone actually use the byte vertices for UVs? How does the mapping work? Does 128,128 represent the equvalent of 1.0f,1.0f?

thanks,

Steve.

Just checked the reference implementation to be sure:

No, it represents -128.00 (GL_BYTE is signed). However you can set the texture transformation matrix to scale the coordinates to the range that you need before going into rasterization.

  • HM

[ June 17, 2004: Message edited by: Hans-Martin Will ]

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