magic4
This commit is contained in:
蔡玲
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<!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>Tadpoles</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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// Adapted from Flocking Processing example by Daniel Schiffman:
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// http://processing.org/learning/topics/flocking.html
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var Boid = Base.extend({
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initialize: function(position, maxSpeed, maxForce) {
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var strength = Math.random() * 0.5;
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this.acceleration = new Point();
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this.vector = Point.random() * 2 - 1;
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this.position = position.clone();
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this.radius = 30;
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this.maxSpeed = maxSpeed + strength;
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this.maxForce = maxForce + strength;
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this.amount = strength * 10 + 10;
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this.count = 0;
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this.createItems();
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},
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run: function(boids) {
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this.lastLoc = this.position.clone();
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if (!groupTogether) {
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this.flock(boids);
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} else {
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this.align(boids);
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}
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this.borders();
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this.update();
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this.calculateTail();
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this.moveHead();
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},
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calculateTail: function() {
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var segments = this.path.segments,
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shortSegments = this.shortPath.segments;
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var speed = this.vector.length;
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var pieceLength = 5 + speed / 3;
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var point = this.position;
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segments[0].point = shortSegments[0].point = point;
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// Chain goes the other way than the movement
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var lastVector = -this.vector;
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for (var i = 1; i < this.amount; i++) {
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var vector = segments[i].point - point;
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this.count += speed * 10;
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var wave = Math.sin((this.count + i * 3) / 300);
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var sway = lastVector.rotate(90).normalize(wave);
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point += lastVector.normalize(pieceLength) + sway;
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segments[i].point = point;
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if (i < 3)
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shortSegments[i].point = point;
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lastVector = vector;
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}
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this.path.smooth();
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},
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createItems: function() {
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this.head = new Shape.Ellipse({
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center: [0, 0],
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size: [13, 8],
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fillColor: 'white'
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});
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this.path = new Path({
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strokeColor: 'white',
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strokeWidth: 2,
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strokeCap: 'round'
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});
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for (var i = 0; i < this.amount; i++)
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this.path.add(new Point());
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this.shortPath = new Path({
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strokeColor: 'white',
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strokeWidth: 4,
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strokeCap: 'round'
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});
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for (var i = 0; i < Math.min(3, this.amount); i++)
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this.shortPath.add(new Point());
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},
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moveHead: function() {
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this.head.position = this.position;
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this.head.rotation = this.vector.angle;
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},
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// We accumulate a new acceleration each time based on three rules
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flock: function(boids) {
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var separation = this.separate(boids) * 3;
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var alignment = this.align(boids);
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var cohesion = this.cohesion(boids);
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this.acceleration += separation + alignment + cohesion;
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},
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update: function() {
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// Update velocity
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this.vector += this.acceleration;
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// Limit speed (vector#limit?)
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this.vector.length = Math.min(this.maxSpeed, this.vector.length);
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this.position += this.vector;
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// Reset acceleration to 0 each cycle
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this.acceleration = new Point();
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},
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seek: function(target) {
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this.acceleration += this.steer(target, false);
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},
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arrive: function(target) {
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this.acceleration += this.steer(target, true);
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},
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borders: function() {
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var vector = new Point();
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var position = this.position;
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var radius = this.radius;
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var size = view.size;
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if (position.x < -radius) vector.x = size.width + radius;
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if (position.y < -radius) vector.y = size.height + radius;
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if (position.x > size.width + radius) vector.x = -size.width -radius;
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if (position.y > size.height + radius) vector.y = -size.height -radius;
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if (!vector.isZero()) {
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this.position += vector;
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var segments = this.path.segments;
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for (var i = 0; i < this.amount; i++) {
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segments[i].point += vector;
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}
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}
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},
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// A method that calculates a steering vector towards a target
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// Takes a second argument, if true, it slows down as it approaches
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// the target
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steer: function(target, slowdown) {
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var steer,
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desired = target - this.position;
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var distance = desired.length;
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// Two options for desired vector magnitude
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// (1 -- based on distance, 2 -- maxSpeed)
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if (slowdown && distance < 100) {
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// This damping is somewhat arbitrary:
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desired.length = this.maxSpeed * (distance / 100);
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} else {
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desired.length = this.maxSpeed;
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}
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steer = desired - this.vector;
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steer.length = Math.min(this.maxForce, steer.length);
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return steer;
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},
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separate: function(boids) {
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var desiredSeperation = 60;
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var steer = new Point();
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var count = 0;
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// For every boid in the system, check if it's too close
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for (var i = 0, l = boids.length; i < l; i++) {
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var other = boids[i];
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var vector = this.position - other.position;
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var distance = vector.length;
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if (distance > 0 && distance < desiredSeperation) {
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// Calculate vector pointing away from neighbor
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steer += vector.normalize(1 / distance);
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count++;
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}
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}
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// Average -- divide by how many
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if (count > 0)
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steer /= count;
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if (!steer.isZero()) {
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// Implement Reynolds: Steering = Desired - Velocity
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steer.length = this.maxSpeed;
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steer -= this.vector;
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steer.length = Math.min(steer.length, this.maxForce);
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}
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return steer;
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},
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// Alignment
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// For every nearby boid in the system, calculate the average velocity
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align: function(boids) {
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var neighborDist = 25;
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var steer = new Point();
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var count = 0;
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for (var i = 0, l = boids.length; i < l; i++) {
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var other = boids[i];
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var distance = this.position.getDistance(other.position);
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if (distance > 0 && distance < neighborDist) {
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steer += other.vector;
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count++;
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}
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}
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if (count > 0)
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steer /= count;
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if (!steer.isZero()) {
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// Implement Reynolds: Steering = Desired - Velocity
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steer.length = this.maxSpeed;
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steer -= this.vector;
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steer.length = Math.min(steer.length, this.maxForce);
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}
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return steer;
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},
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// Cohesion
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// For the average location (i.e. center) of all nearby boids,
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// calculate steering vector towards that location
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cohesion: function(boids) {
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var neighborDist = 100;
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var sum = new Point();
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var count = 0;
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for (var i = 0, l = boids.length; i < l; i++) {
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var other = boids[i];
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var distance = this.position.getDistance(other.position);
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if (distance > 0 && distance < neighborDist) {
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sum += other.position; // Add location
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count++;
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}
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}
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if (count > 0) {
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sum /= count;
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// Steer towards the location
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return this.steer(sum, false);
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}
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return sum;
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}
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});
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var heartPath = new Path('M514.69629,624.70313c-7.10205,-27.02441 -17.2373,-52.39453 -30.40576,-76.10059c-13.17383,-23.70703 -38.65137,-60.52246 -76.44434,-110.45801c-27.71631,-36.64355 -44.78174,-59.89355 -51.19189,-69.74414c-10.5376,-16.02979 -18.15527,-30.74951 -22.84717,-44.14893c-4.69727,-13.39893 -7.04297,-26.97021 -7.04297,-40.71289c0,-25.42432 8.47119,-46.72559 25.42383,-63.90381c16.94775,-17.17871 37.90527,-25.76758 62.87354,-25.76758c25.19287,0 47.06885,8.93262 65.62158,26.79834c13.96826,13.28662 25.30615,33.10059 34.01318,59.4375c7.55859,-25.88037 18.20898,-45.57666 31.95215,-59.09424c19.00879,-18.32178 40.99707,-27.48535 65.96484,-27.48535c24.7373,0 45.69531,8.53564 62.87305,25.5957c17.17871,17.06592 25.76855,37.39551 25.76855,60.98389c0,20.61377 -5.04102,42.08691 -15.11719,64.41895c-10.08203,22.33203 -29.54687,51.59521 -58.40723,87.78271c-37.56738,47.41211 -64.93457,86.35352 -82.11328,116.8125c-13.51758,24.0498 -23.82422,49.24902 -30.9209,75.58594z');
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var boids = [];
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var groupTogether = false;
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// Add the boids:
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for (var i = 0; i < 30; i++) {
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var position = Point.random() * view.size;
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boids.push(new Boid(position, 10, 0.05));
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}
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function onFrame(event) {
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for (var i = 0, l = boids.length; i < l; i++) {
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if (groupTogether) {
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var length = ((i + event.count / 30) % l) / l * heartPath.length;
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var point = heartPath.getPointAt(length);
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if (point)
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boids[i].arrive(point);
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}
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boids[i].run(boids);
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}
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}
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// Reposition the heart path whenever the window is resized:
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function onResize(event) {
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heartPath.fitBounds(view.bounds);
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heartPath.scale(0.8);
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}
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function onMouseDown(event) {
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groupTogether = !groupTogether;
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}
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function onKeyDown(event) {
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if (event.key == 'space') {
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var layer = project.activeLayer;
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layer.selected = !layer.selected;
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return false;
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}
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}
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</script>
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<style>
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body {
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background: black;
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}
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</style>
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</head>
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<body>
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<canvas id="canvas" resize></canvas>
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</body>
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</html>
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