jpegs not suitable?

Karen Pouelle hockeyvixen at yahoo.ca
Wed Jul 23 17:47:31 EDT 2003


"IMHO jpeg isn't a suitable format if you want high quality textures, see
http://www.sjbaker.org/steve/omniv/jpegs_are_evil_too.html " -- Christian Ohm

To touch on some of the things mentioned in the article:

"JPEG has no way to store an alpha channel - so images cannot have
translucent areas."  

This one's not a problem. The textures contain no alpha.  There's no point in
seeing thru walls except as a cheat.

"However, the assumptions they make are that the image is presented at a
uniform scale at the designed brightness, with pre-processed gamma correction
and at fairly high resolution. "

Indeed they are lossy, even at maximum quality.  However, they're still 2 x
smaller than the most optimal compression of png's of the same, and nearly
exact visually even in-game, despite this. 

"Don't even think of converting your JPEGs back into something else..."

That's why they're stored as (lossless) PNG's in the CVS, in case someone'd
like to take the texture and use it as a base for another, or remake the
texture and resubmit it.  The authors of the textures allow for modifications
of their textures provided they're used to construct other textures for Quake
2 (but not for some other game, especally a comercial one).

If you want a PNG texture pak, let me know - but it will be twice the size
and probably less than twice the quality improvement.  I dread having to
maintain two seperate versions of the pak files.  If all the textures were
submitted, then it'd be no big deal, but I'm updating these at least once a
week.  

See the mini-faq.txt at http://3d.kicks-ass.net/texturepaks/ as to why you
might have some trouble seeing a difference at 320 x 200.  Meanwhile, it's
time to post some screenshots, so people know what they're looking at.  :) 

I'll do a bit more work on the faq now.  Thank you for all the questions.

Karen


=====
http://pretzel.iceware.net/

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