[fpc-pascal] GLM library alternative?

[Marco van de Voort]

In our previous episode, Anthony Walter said:
> 
> This type of 2D setup in OpenGL allows for allows you to freely mix in both
> 2D and 3D effects. Here's are two examples of how 2D in a 3D world can work:

If you check the myorthohelp function that called it, you'll already see it
is normalized to [0..1] coordinates.

But there are some special cases (e.g. sometimes zoomx<>zoomy to get square
pixels), vertical inversion etc where not everything is 0..1,0..1

I don't need 3D effects, this is a business app. For an (older) demo based
on the code see

http://forum.lazarus.freepascal.org/index.php/topic,30556.msg194484.html#msg194484