[PD] playing a video with an offset

IOhannes zmoelnig zmoelnig at iem.kug.ac.at
Tue Dec 30 11:09:26 CET 2003

cgc at humboldtblvd.com wrote:
> Quoting zmoelnig at iem.at:
>>[pix_coordinate] is quite likely to not work
>>properly with non-power-of-2 textures.
> It does work.  Use 0..height and 0..width instead of the normalized 0..1 
> values.  The only limitation lies in the lack of repeat mode for the mapping - 
> clamp to edge is the only one supported so far.

oh sorry.
of course you are right with this.
but in my opinion this is not really "work properly" (although it is 
the discussion might turn out similar to the "float" vs. "int" talk @ 

now: what i really like about normalized values is, that they are 
abstracted and independent (aka: "normalized") .

short discussion of making [pix_coordinate] use normalized coordinates:
+ you don't have to know/care whether your pixImage is power-of-two or 
not (same point as in super-dooper-everything [pix_texture] vs. 
+ if your image is non-power-of-2 you don't have to know the dimensions.
- not openGL-comformant
- work to do.

i don't really understand why non-power-of-2 textures became such 
problems or rather: why implementations turned out to do it that 
complicated and if it was for quality's sake, why they didn't do it 
twice: once with normalized and once with not-normalized tex-coordinates 
(this is how openGL handles is anyway: provide umpteen functions for the 
same functionality in case someone wanted it to do it this or that way)


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