private static float crossProductZ ( ResultPoint pointA , ResultPoint pointB , ResultPoint pointC ) { float bX = pointB . x ; float bY = pointB . y ; return ( ( pointC . x - bX ) * ( pointA . y - bY ) ) - ( ( pointC . y - bY ) * ( pointA . x - bX ) ) ; }
Returns the z component of the cross product between vectors BC and BA .