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This test is based on code written by Cameron Adams and imported from
  http://themaninblue.com/experiment/AnimationBenchmark/html
-->

<!doctype html>
<head>
<title>Benchmark - Balls Animation using CSS and requestAnimationFrame</title>
<style>
html {
    height: 100%;
}

body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    margin: 0;
    padding: 0;
}

span {
    position: absolute;
    width: 12px;
    height: 12px;
    border-radius: 6px;
}
</style>
<script src="../resources/runner.js"></script>
<script src="resources/framerate.js"></script>
<script>
var stageWidth = 600;
var stageHeight = 600;
var maxParticles = 2500;
var minVelocity = 50;
var maxVelocity = 500;
var particleRadius = 6;
var colors = ["#cc0000", "#ffcc00", "#aaff00", "#0099cc", "#194c99", "#661999"];

var testRunning = true;
var particles = [];
var prevTime;

window.onload = function () {
    PerfTestRunner.prepareToMeasureValuesAsync({done: onCompletedRun, unit: 'fps'});

    // Create the particles
    for (var i = 0; i < maxParticles; i++)
        particles.push(new Particle());

    // Start the animation
    prevTime = PerfTestRunner.now();
    animate();
    startTrackingFrameRate();
}

function animate()
{
    var currTime = PerfTestRunner.now();
    var timeDelta = currTime - prevTime;

    // Draw each particle
    for (var particle in particles)
        particles[particle].draw(timeDelta);

    prevTime = currTime;

    if (testRunning)
        requestAnimationFrame(animate);
}

function Particle()
{
    var angle = Math.PI * 2 * PerfTestRunner.random();
    var velocity = minVelocity + ((maxVelocity - minVelocity) * PerfTestRunner.random());
    var x = stageWidth / 2 - particleRadius;
    var y = stageHeight / 2 - particleRadius;
    var dx = Math.cos(angle) * velocity;
    var dy = Math.sin(angle) * velocity;

    // Create visual element for the particle
    var domNode = document.createElement('span');
    document.body.appendChild(domNode);

    // Set initial position to middle of screen
    domNode.style.left = x + "px";
    domNode.style.top = y + "px";

    // Set colour of element
    domNode.style.backgroundColor = colors[Math.floor(Math.random() * colors.length)];

    function destroy()
    {
        document.body.removeChild(domNode);
    }

    function draw(timeDelta)
    {
        var timeDeltaSeconds = timeDelta / 1000;
        var testX = x + (dx * timeDeltaSeconds);
        var testY = y + (dy * timeDeltaSeconds);

        if (testX < 0 || testX > stageWidth) {
            dx = -dx;
            x += dx;
        } else {
            x = testX;
        }
        if (testY < 0 || testY > stageHeight) {
            dy = -dy;
            y += dy;
        } else {
            y = testY;
        }

        domNode.style.left = x + "px";
        domNode.style.top = y + "px";
    }

    this.draw = draw;
    this.destroy = destroy;
}

function onCompletedRun() {
    stopTrackingFrameRate();

    for (var i = 0; i < particles.length; i++)
        particles[i].destroy();
    particles = [];
}
</script>
</head>
</html>