How to recreate the Darwinian soul glow effect?

[taynaron]

I'm currently working on a simulation visualization of ant pathing as part of my thesis, and part of that visualization involves a glow effect which I'd like to be very similar to the "soul glow" found in Darwinia, specifically in the main world screen. Could anyone help me figure out how to emulate/reproduce the glow effect in OpenGL?
Thanks for your help.

[xander]

I am not sure exactly what you are referring to, but I believe that IV just used a sprite.

xander

[taynaron]

The glow effect I'm talking about is here:
I'm almost positive that the souls themselves are sprites, but is the background glow also a sprite? That seems unlikely given the glowing center, unless that's done with a separate sprite.

[xander]

Actually, I am not sure that the souls themselves are sprites. If you look through the data files, there is no sprite for the souls. However, the glow effect is a sprite -- namely, glow.bmp -- which as been shaded with a particular color and placed with the sprite.

xander

[taynaron]

Hm, interesting. I suppose that would be a much more efficient method for point-glow sources than a separate rendering pass. I suppose the glow textures are just added or multiplied together for the glow in the center.
Thanks for the help. If anyone has more in-depth explanations, I'd appreciate that as well. If not, knowing in which direction to look is a good start.