rel_for_screen (VECTOR*, VIEW*);
Convert the vector's screen coordinates into xyz-coordinates of the given view. Contrary to vec_for_screen, the view angle and positions is not used in this calculation. Thus the resulting coordinates can be directly used for positioning a view entity. If the result is invalid - outside the screen - the command returns 0, otherwise a nonzero value.

Parameters:
VECTOR* screen position to be converted to 3D.
VIEW* view used for the conversion, must be VISIBLE.

Returns:
0 position is outside the view.
!= 0 position is inside the view