Ehh there are 2 particles that jump to the mouses location and out of habit I made it get the size - 1 instead of just size.

And yeah I tried the full-screen method you said but when I did glOrtho to the new size, it retained the original ortho, 800x600.
The only thing I want to change in it, is letting the user define the chance that a particle will be a "space dust" particle or a star particle.
Looks more realistic with less stars and more dust. I also wanted to colorize a gray scale texture so there is much more variety in the textures but ehh whateverz.
[Edit]
No you were right it was creating 5001/501 particles. I had thought I put the 2 "pulling" particles in the array but I did not.
my for loop had "<= 5000" and it starts at 0. So 5001 particles. Lulz