[GEM-dev] [GEM] pix_coordinate in OS X

[Mirko Petrovich]

On Oct 20, 2004, at 4:06 AM, IOhannes m zmoelnig wrote:

> Mirko Petrovich wrote:
>> Thanks, that did the trick. One thing I didn't understand is what do 
>> you mean when you say "rectangle textures" ? And which textures can 
>> be repeated ?Is this documented somewhere ?
>
> originally openGL only supported textures which sizes where power-of-2.
> e.g.: you could texture an image with a size of 256x256 pixels; but 
> when you tried to texture an image that was 100x100 (or 320x240) this 
> would not work.
>
> this limitation is very unpractical, especially when working with 
> videos (which tend to have dimensions like 320x240); therefore the 
> openGL-standard has been extended to support textures of any 
> dimension: these are called "rectangle textures" in openGL-speak.
> unfortunately they do not perform exactly like the old 2^n-textures 
> ("normalized" you call them); e.g. "repeat" does not work, only 
> "clamp", texture coordinates are completely different,...
>
> documentation can be found in the openGL-standard ;-)
> seriously, the help-patch for [pix_texture] mentions this limitation.

OK, now I understand, thanks for your explanation. But in Linux repeat 
"works" for rectangle textures (I guess [pix_texture] resizes 
automatically), and there's no difference with "mode" messages (there's 
only mention of "quality" messages in help-patches, that's why I was 
asking for documentation).

>
>
>> Thanks again for your answer, and congratulations, gem works great in 
>> osx.
>
> good to hear.

well, it works great in Linux too ;-)

saludos from Chile

Mirko