Create vectors and collisions

Question

I have a ball and a stick (for a billiard game).

First the ball is placed in a position of a table. On clicking the ball the stick appears, in such a way that we ca

Answer 1

You calculate the angle of the billiard stick to the ball like this:

var dx = ballX - stickX;
var dy = ballY - stickY;
var angle = Math.atan2(dy,dx);

Then you can move the ball along that angle like this:

var newBallX = ballX + desiredRollDistance * Math.cos(angle);
var newBallY = ballY + desiredRollDistance * Math.sin(angle);

Your desired roll distance would be based on how far the stick was drawn back away from the ball.

The further the stick was drawn back == the further the ball would travel.

You can calculate the distance from the stick to the ball like this:

var dx = ballX - stickX;
var dy = ballY - stickY;
var lengthFromStickToBall = Math.sqrt(dx*dx+dy*dy);

Here is a Demo: http://jsfiddle.net/m1erickson/B6K9z/