There is more code after that 0.0f, you can see the scrollbar under that section of code. Scroll to the right. If you can't see it, use Firefox, Chrome, or Opera.
Check out line 1825, I think there's code there something to do with the glow. Fire, plasma, lava, and spark all have the glow, and they're all listed there.
singularity:
Detailed tut and I will be happy.
If you are not willing to look things up yourself, for example, searching "Fire" in the code to look for any code related to the glow, developing will only get harder as you create more complicated elements.