Billard

<div id="wrapperId" style="width:100vmin; height:50vmin; ">
<canvas id="canvasId" style="width:100%; height:100%; border:thin solid;"></canvas>
</div><!-- wrapperId -->

<script type="text/javascript"> 
var canvas = document.getElementById("canvasId");
var ctx = canvas.getContext("2d");
var raf;

var ball = {
  x: 100,
  y: 100,
  vx: 5,
  vy: 2,
  radius: 25,
  color: "blue",
  draw: function () {
    ctx.beginPath();
    ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, true);
    ctx.closePath();
    ctx.fillStyle = this.color;
    ctx.fill();
  },
};

function draw() {
  	ctx.clearRect(0, 0, canvas.width, canvas.height);
 	ball.draw();
  	ball.x += ball.vx;
  	ball.y += ball.vy;
  	raf = window.requestAnimationFrame(draw);
  	if (ball.y + ball.vy > canvas.height || ball.y + ball.vy < 0) {
  		ball.vy = -ball.vy;
		}
	if (ball.x + ball.vx > canvas.width || ball.x + ball.vx < 0) {
  		ball.vx = -ball.vx;
		}
	}

canvas.addEventListener("mouseover", function (e) {
  raf = window.requestAnimationFrame(draw);
});

canvas.addEventListener("mouseout", function (e) {
  window.cancelAnimationFrame(raf);
});

ball.draw();
	
</script>