mirror of
https://github.com/scratchfoundation/paper.js.git
synced 2024-12-29 09:22:22 -05:00
122 lines
4 KiB
HTML
122 lines
4 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8">
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<title>Future Splash</title>
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<link rel="stylesheet" href="../css/style.css">
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<script type="text/javascript" src="../../dist/paper-full.js"></script>
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<script type="text/paperscript" canvas="canvas">
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// Code ported to Paper.js from http://the389.com/9/1/
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// with permission.
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var values = {
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friction: 0.8,
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timeStep: 0.01,
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amount: 15,
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mass: 2,
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count: 0
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};
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values.invMass = 1 / values.mass;
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var path, springs;
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var size = view.size * [1.2, 1];
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var Spring = function(a, b, strength, restLength) {
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this.a = a;
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this.b = b;
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this.restLength = restLength || 80;
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this.strength = strength ? strength : 0.55;
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this.mamb = values.invMass * values.invMass;
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};
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Spring.prototype.update = function() {
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var delta = this.b - this.a;
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var dist = delta.length;
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var normDistStrength = (dist - this.restLength) /
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(dist * this.mamb) * this.strength;
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delta.y *= normDistStrength * values.invMass * 0.2;
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if (!this.a.fixed)
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this.a.y += delta.y;
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if (!this.b.fixed)
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this.b.y -= delta.y;
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};
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function createPath(strength) {
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var path = new Path({
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fillColor: 'black'
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});
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springs = [];
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for (var i = 0; i <= values.amount; i++) {
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var segment = path.add(new Point(i / values.amount, 0.5) * size);
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var point = segment.point;
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if (i == 0 || i == values.amount)
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point.y += size.height;
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point.px = point.x;
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point.py = point.y;
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// The first two and last two points are fixed:
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point.fixed = i < 2 || i > values.amount - 2;
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if (i > 0) {
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var spring = new Spring(segment.previous.point, point, strength);
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springs.push(spring);
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}
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}
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path.position.x -= size.width / 4;
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return path;
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}
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function onResize() {
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if (path)
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path.remove();
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size = view.bounds.size * [2, 1];
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path = createPath(0.1);
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}
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function onMouseMove(event) {
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var location = path.getNearestLocation(event.point);
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var segment = location.segment;
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var point = segment.point;
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if (!point.fixed && location.distance < size.height / 4) {
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var y = event.point.y;
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point.y += (y - point.y) / 6;
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var previous = segment.previous && segment.previous.point;
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var next = segment.next && segment.next.point;
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if (previous && !previous.fixed)
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previous.y += (y - previous.y) / 24;
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if (next && !next.fixed)
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next.y += (y - next.y) / 24;
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}
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}
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function onFrame(event) {
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updateWave(path);
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}
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function updateWave(path) {
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var force = 1 - values.friction * values.timeStep * values.timeStep;
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for (var i = 0, l = path.segments.length; i < l; i++) {
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var point = path.segments[i].point;
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var dy = (point.y - point.py) * force;
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point.py = point.y;
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point.y = Math.max(point.y + dy, 0);
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}
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for (var j = 0, l = springs.length; j < l; j++) {
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springs[j].update();
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}
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path.smooth({ type: 'continuous' });
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}
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function onKeyDown(event) {
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if (event.key == 'space') {
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path.fullySelected = !path.fullySelected;
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path.fillColor = path.fullySelected ? null : 'black';
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}
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}
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</script>
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</head>
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<body>
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<canvas id="canvas" resize hidpi="off"></canvas>
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</body>
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</html>
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