[PD] Gem coordinates / OpenGL

[cyborgk at nocturnalnoize.com]

Okay, THIS is exactly what I needed to know. Very helpful! I couldn't
figure out why the hell my width was 5 and a fraction, but now, that makes
perfect sense (even if it's a little arbitrary, I see the logic in it).
I'll definitely check the tutorials.

The funny thing is, without knowing many things, I still had no problem
creating a live video/animation program which ran "good enough" to do live
visuals at a party in Chicago. However, I skipped things that seemed weird
or didn't work, to figure out later...

I'm definitely going to at least keep doing generative stuff in GEM. Looks
like video in GEM, on PC isn't much of an option right now, I really need
AVI's, cus I use Virtual Dub to do the edits. Unless someone knows of a
simple AVI-QT converter, because I don't have any easy way to make
QuickTime movies... Well, I'll try the 0.87 GEM to see if it is better,
before I give up.

~David

> Gem coords really only represent distances relative to the window aspect
> ratio.
>
> 0,0,0 is in the middle, -4,-4,0 is the bottom left corner 4,4,0 is the
> upper right corner. The camera is at 0,0,4...
>
> That is for a square window.
>
> The height of a gemwindow is always 8 units, -4 to 4, but depending on
> the aspect ratio of the window the number of units wide changes. for a
> 2:1 window the left edge is -8 and the right 8. For a 4:3 window the
> left is -5.333 and the right 5.333
>
> try the tutorial at www.ekran.org/pd
>
> ..b.
>