range_ring_instanced.fs

This is responsible for rendering range rings like patrol circle, mex area commands and that kind of thing.

What I have worked out so far: When a range is being rendered, a huge low poly sphere is used as a scaffold. (I call it a scaffold because it is really just used to generate fragments for the fragment shader that is not too wasteful.

The sphere is centred on the origin of the unit/range and is sized to encompass the range of the unit.