public static int dot ( Point v1s , Point v1e , Point v2s , Point v2e ) { return ( ( v1e . x - v1s . x ) * ( v2e . x - v2s . x ) + ( v1e . y - v1s . y ) * ( v2e . y - v2s . y ) ) ; }
Computes and returns the dot product of the two vectors .