<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Bouncing Balls</title>
<link rel="stylesheet" href="../css/style.css">
<script type="text/javascript" src="../../dist/paper.js"></script>
<script type="text/paperscript" canvas="canvas">
var balls = [];
var group = new Group();
var Ball = Base.extend({
initialize: function(point, vector) {
if (!vector || vector.isZero()) {
this.vector = Point.random() * 5;
} else {
this.vector = vector * 2;
}
this.point = point;
this.dampen = 0.4;
this.gravity = 3;
this.bounce = -0.6;
this.radius = 50 * Math.random() + 30;
this.createPaths();
group.addChild(this.item);
},
createPaths: function() {
var overlayPos = this.point + this.radius / 8;
var compound = new CompoundPath([
new Path.Circle(this.point, this.radius),
new Path.Circle(overlayPos, this.radius / 2)
]);
var color = new HsbColor(Math.random() * 360, 1, 1);
var gradient = new Gradient([color, 'black'], 'radial');
compound.children[0].fillColor = new GradientColor(gradient, this.point,
this.point + this.radius, overlayPos);
var overlay = new Path.Circle(overlayPos, this.radius / 2);
var overlayColor = color.clone();
var fullOverlay = color.clone();
overlayColor.alpha = 0.5;
var overlayGradient = new Gradient([new RgbColor(1, 1, 1, 0.5), new RgbColor(1, 1, 1, 1)]);
overlay.fillColor = new GradientColor(overlayGradient, overlayPos, overlayPos + this.radius / 2);
this.item = new Group([compound, overlay]);
},
iterate: function() {
var size = view.size;
this.vector.y += this.gravity;
this.vector.x *= 0.99;
var pre = this.point + this.vector;
if (pre.x < this.radius || pre.x > size.width - this.radius)
this.vector.x *= -this.dampen;
if (pre.y < this.radius || pre.y > size.height - this.radius) {
if (Math.abs(this.vector.x) < 3)
this.vector = Point.random() * [150, 100] + [-75, 20];
this.vector.y *= this.bounce;
}
var max = Point.max(this.radius, this.point + this.vector);
this.item.position = this.point = Point.min(max, size - this.radius);
this.item.rotate(this.vector.x / 2);
}
});
for (var i = 0; i < 10; i++) {
var position = Point.random() * view.size,
vector = (Point.random() - [0.5, 0]) * [50, 100],
ball = new Ball(position, vector);
balls.push(ball);
}
var textItem = new PointText(20, 30);
textItem.fillColor = 'black';
textItem.content = 'Click, drag and release to add balls.'
var lastDelta;
function onMouseDrag(event) {
lastDelta = event.delta;
}
function onMouseUp(event) {
var ball = new Ball(event.point, lastDelta);
balls.push(ball);
lastDelta = null;
}
function onFrame() {
for (var i = 0, l = balls.length; i < l; i++)
balls[i].iterate();
}
</script>
</head>
<body>
<canvas id="canvas" resize></canvas>
</body>
</html>