I know probably there're already solutions to this problem, but I cant't find them. The problem is that I have a player which can be moved by arrow keys and rotate towards the mouse coordinates, and has a vx and a vy properties. When I fire a bullet, it goes towards the mouse too and also has a vx and a vy properties, but if the player is moving towards the mouse, it overcomes the bullets or it seems the bullets are moving slower. I tried to add to the bullets' vx and vy the ship's vx and vy, but it doesn't work (some bullets move faster than the others). How can I solve the problem?