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12-time-based-1.html
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12-time-based-1.html
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<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Time Based 1</title>
<link rel="stylesheet" href="../include/style.css">
</head>
<body>
<header>
Example from <a href="http://amzn.com/1430236655?tag=html5anim-20"><em>Foundation HTML5 Animation with JavaScript</em></a>
</header>
<canvas id="canvas" width="400" height="400"></canvas>
<script src="../include/utils.js"></script>
<script src="./classes/ball.js"></script>
<script>
window.onload = function () {
var canvas = document.getElementById('canvas'),
context = canvas.getContext('2d'),
ball = new Ball(),
start_time = new Date().getTime(),
time = getTimer(),
vx = 300,
vy = -300,
bounce = -0.7;
ball.x = canvas.width * Math.random();
ball.y = canvas.height / 2;
function getTimer () {
return (new Date().getTime() - start_time); //milliseconds
}
(function drawFrame () {
window.requestAnimationFrame(drawFrame, canvas);
context.clearRect(0, 0, canvas.width, canvas.height);
var elapsed = getTimer() - time,
left = 0,
right = canvas.width,
top = 0,
bottom = canvas.height;
time = getTimer();
ball.x += vx * elapsed / 1000;
ball.y += vy * elapsed / 1000;
if (ball.x + ball.radius > right) {
ball.x = right - ball.radius;
vx *= bounce;
} else if (ball.x - ball.radius < left) {
ball.x = left + ball.radius;
vx *= bounce;
}
if (ball.y + ball.radius > bottom) {
ball.y = bottom - ball.radius;
vy *= bounce;
} else if (ball.y - ball.radius < top) {
ball.y = top + ball.radius;
vy *= bounce;
}
ball.draw(context);
}());
};
</script>
</body>
</html>