/// A wall is static. So it just gives the impulse back
/// But it gives it back, based on the kind of wall.
METHOD COLLIDE : BOOL
VAR_INPUT
posIn : POSITION;
vecIn : VECTOR;
END_VAR
VAR_OUTPUT
// only north and south walls are installed
// So we just have to reflect the y force of the vector
vecOut := vecIn;
IF posIn.iXPos <= 0 OR posIn.iXPos >= iWidth THEN
vecOut.rVX := 0;
vecOut.rVY := 0;
COLLIDE := TRUE;
END_IF