FTR: Advanced Smoke Physics

[proof88]

Smoke particles shall also collide with walls.
This requires that clients should also run this kind of smoke physics on their side to minimize network traffic.
But still some sync might be required between server and clients about smoke particles.

Note that not any kind of smoke would be affected. To minimize performance penalty, smoke emitted by rockets, jetlax, etc. would not be affected.
Only other kind of smoke like smoke grenade would be affected.

Smoke grenade would be a network-sync'd smoke emitter. The emitted smoke would be colliding with walls.

Note that since we want this kind of smoke to hide players and items, Z-pos of this kind of smoke needs to be closer to camera. But, rendering of transparent/blended objects must be Z-ordered for correct rendering, therefore the Z-ordered rendering path must be enabled in PURE for this feature to work properly.