Heat system

[Doom2fan]

Hideous Destructor has something like this, and it could make thermal weapons more interesting.

• Would apply to things like the incendiary grenades, and the plasma weapons
• Could be applied as an area effect to other nearby actors
• Don't "build up" heat indefinitely, though. Things should only be able to get as hot as the fire that heats them up, unless they can, themselves, properly ignite and burn
• Ignition temperatures, thermal conductivity.
• "Burning material" actors that stick to the actor and add heat for a few seconds.