View Full Version : Texture Compression and byte sized verts.

Steven Haggerty
06-14-2004, 01:49 AM
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.



06-16-2004, 05:16 AM
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).


Steven Haggerty
06-16-2004, 09:01 PM
Fantastic, that's made my life a whole of easier, thanks Jani.

Steven Haggerty
06-17-2004, 03:48 AM
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?



06-17-2004, 05:46 AM
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 ]