HTML and CSS Reference
In-Depth Information
Example 5-8. Balls with friction
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>CH5EX8: Balls With Friction</title>
<script src="modernizr-1.6.min.js"></script>
<script type="text/javascript">
window.addEventListener('load', eventWindowLoaded, false);
function eventWindowLoaded() {
canvasApp();
}
function canvasSupport () {
return Modernizr.canvas;
}
function canvasApp() {
if (!canvasSupport()) {
return;
}
function drawScreen () {
context.fillStyle = '#EEEEEE';
context.fillRect(0, 0, theCanvas.width, theCanvas.height);
//Box
context.strokeStyle = '#000000';
context.strokeRect(1, 1, theCanvas.width-2, theCanvas.height-2);
update();
testWalls();
collide();
render();
}
function update() {
for (var i = 0; i <balls.length; i++) {
ball = balls[i];
//Friction
ball.velocityx = ball.velocityx - ( ball.velocityx*friction);
ball.velocityy = ball.velocityy - ( ball.velocityy*friction);
ball.nextx = (ball.x += ball.velocityx);
ball.nexty = (ball.y += ball.velocityy);
}
}
function testWalls() {
var ball;
var testBall;
