Shakes the screen using the fall.envshake parameters set by an attack (see HitDef controller). This controller is effective only if GetHitVar(fall.envshake.time) is not zero, and it sets GetHitVar(fall.envshake.time) to zero after being executed. This controller is used in common1.cns to shake the screen when a player falls, and is not normally useful otherwise.

Required parameters:

- none

Optional parameters:

- none

Example:

`none`