NAME
        DoCollision -- Test every gel in gel list for collisions.

   SYNOPSIS
        DoCollision(rp)
                    A1

        void DoCollision(struct rastport *);

   FUNCTION
        Tests each gel in gel list for boundary and gel-to-gel collisions.
        On detecting one of these collisions, the appropriate collision-
        handling routine is called. See the documentation for a thorough
        description of which collision routine is called. This routine
        expects to find the gel list correctly sorted in Y,X order.
        The system routine sortglist performs this function for the user.

   INPUTS
        rp = pointer to a rastport

   RESULT

   BUGS

   SEE ALSO
        initgels()  sortglist()  graphics/gels.h  graphics/gels.h