// rectangle objects { x:, y:, width:, height: }
// return true if the 2 rectangles are colliding
// r1 and r2 are rectangles as defined above
function RectsColliding(r1,r2){
return !(
r1.x>r2.x+r2.width ||
r1.x+r1.width<r2.x ||
r1.y>r2.y+r2.height ||
r1.y+r1.height<r2.y
);
}