vfx

Fog

The call script is :-

vfx.Fog(clip [,int sf = 0][,int ef = end frame][, float fog = 0.5 ][,float efog = fog][, float vary = 0.1 * fog ])

clip: input clip of constant format. Compat input not accepted.
sf: Effect Start Frame Number
ef: Effect End Frame Number
fog: Fog density 0 to 0.9.
efog: Fog density at end 0 to 0.9.
vary: variation. Fog density + vary should not exceed 1.0

This function creates fog which can linearly vary during effect.