Two minor graphical suggestions

[Ingolifs]

1. There is a sharp and noticeable border between live trees and trees killed by pollution.

foresttrees.png (710 KiB) Viewed 853 times

Instead of a tree dying once it has absorbed 5000 pollution units (or whatever value it is), perhaps it has a small chance of dying per second upon reaching this value, or perhaps trees have a random value that varies between n and 2n that must be exceeded in order for them to die.

This would have the effect of creating a gradient of alive and dead trees, rather than a sudden cutoff, and would make it look more natural and aesthetically pleasing (or as aesthetically pleasing as poisoned trees can be).

2. The tank's treads don't move when it rotates on its axis. It looks kinda weird. This could be easily fixed by using the normal move animation while rotating.

Strictly speaking, each of the treads should be moving in the opposite direction, but I reckon you could get away with not animating this detail.

[Rseding91]

The trees thing is not likely to ever be changed. Doing anything "every few ticks" means it would drain a massive amount of performance for virtually no gains.

Even as it is now they still take a measurable amount of time to "damage" the trees from pollution that I've done some optimizations around them for 0.15.