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bc2729683c
- Symbol -> SymbolDefinition - PlacedSymbol -> SymbolItem - Symbol#definition -> SymbolDefinition#item - PlacedSymbol#symbol -> SymbolItem#definition - Deprecate Project#symbols Closes #770
278 lines
8.2 KiB
Text
278 lines
8.2 KiB
Text
// Adapted from Flocking Processing example by Daniel Schiffman:
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// http://processing.org/learning/topics/flocking.html
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project.currentStyle = {
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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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new Path.Rectangle(view.bounds).fillColor = 'black';
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var head = new Path.Ellipse([0, 0], [13, 8]);
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head.fillColor = 'white';
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head.strokeColor = null;
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var headSymbol = new SymbolDefinition(head);
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var size = view.size;
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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.acc = new Point(0, 0);
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this.vel = Point.random() * 2 - 1;
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this.loc = position.clone();
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this.r = 30;
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this.maxSpeed = maxSpeed + strength;
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this.maxForce = maxForce + strength;
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this.head = headSymbol.place();
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this.path = new Path();
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this.shortPath = new Path();
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this.shortPath.strokeWidth = 4;
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for (var i = 0, l = strength * 10 + 10; i < l; i++) {
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this.path.add(this.loc);
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if (i < 3)
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this.shortPath.add(this.loc);
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}
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this.firstSegment = this.path.segments[0];
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this.count = 0;
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this.lastRot = 0;
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},
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run: function(boids) {
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this.lastLoc = this.loc.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.firstSegment.point = this.loc;
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var lastPoint = this.firstSegment.point;
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var lastVector = this.loc - this.lastLoc;
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var segments = this.path.segments;
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for (var i = 1, l = segments.length; i < l; i++) {
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var segment = segments[i];
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var vector = lastPoint - segment.point;
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this.count += this.vel.length * 10;
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var rotLength = Math.sin((this.count + i * 3) / 300);
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var rotated = lastVector.rotate(90).normalize(rotLength);
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lastPoint += lastVector.normalize(-5 - this.vel.length / 3);
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segment.point = lastPoint;
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segment.point += rotated;
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lastVector = vector;
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}
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this.path.smooth();
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this.head.position = this.loc;
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var vector = this.loc - this.lastLoc;
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var rot = vector.angle;
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this.head.rotate(rot - this.lastRot);
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this.lastRot = rot;
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var shortSegments = this.shortPath.segments;
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for (var i = 0; i < 3; i++)
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shortSegments[i] = segments[i].clone();
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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 sep = this.separate(boids) * 3;
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var ali = this.align(boids);
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var coh = this.cohesion(boids);
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this.acc += sep + ali + coh;
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},
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update: function() {
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// Update velocity
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this.vel += this.acc;
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// Limit speed (vector#limit?)
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this.vel.length = Math.min(this.maxSpeed, this.vel.length);
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this.loc += this.vel;
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// Reset acceleration to 0 each cycle
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this.acc.length = 0;
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},
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seek: function(target) {
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this.acc += this.steer(target, false);
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},
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arrive: function(target) {
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this.acc += this.steer(target, true);
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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.loc,
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d = desired.length;
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if (d > 0) {
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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 && d < 100) {
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// // This damping is somewhat arbitrary:
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desired.length = this.maxSpeed * (d / 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.vel;
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steer.length = Math.min(this.maxForce, steer.length);
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} else {
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steer = new Point(0, 0);
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}
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return steer;
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},
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borders: function() {
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var loc = this.loc;
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var r = this.r;
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var oldLoc = this.loc.clone();
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var width = size.width;
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var height = size.height;
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if (loc.x < -r) loc.x = width + r;
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if (loc.y < -r) loc.y = height + r;
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if (loc.x > width + r) loc.x = -r;
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if (loc.y > height + r) loc.y = -r;
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var vector = this.loc - oldLoc;
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if (!vector.isZero())
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this.path.position += vector;
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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(0, 0);
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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 d = other.loc.getDistance(this.loc);
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if (d > 0 && d < desiredSeperation) {
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// Calculate vector pointing away from neighbor
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var diff = this.loc - other.loc;
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steer += diff.normalize(1 / d);
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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.length > 0) {
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// Implement Reynolds: Steering = Desired - Velocity
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steer.length = this.maxSpeed;
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steer -= this.vel;
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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(0, 0);
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var count = 0;
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var nearest = 999;
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var closestPoint;
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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 d = this.loc.getDistance(other.loc);
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if (d > 0 && d < nearest) {
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closestPoint = other.loc;
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nearest = d;
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}
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if (d > 0 && d < neighborDist) {
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steer += other.vel;
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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.length > 0) {
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// Implement Reynolds: Steering = Desired - Velocity
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steer.length = this.maxSpeed;
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steer -= this.vel;
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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(0, 0);
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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 d = this.loc.getDistance(other.loc);
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if (d > 0 && d < neighborDist) {
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sum += other.loc; // 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([
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[[514.6962890625, 624.703125], [7.0966796875, -26.3369140625], [-7.10205078125, -27.0244140625]],
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[[484.29052734375, 548.6025390625], [13.16845703125, 23.7060546875], [-13.173828125, -23.70703125]],
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[[407.84619140625, 438.14453125], [37.79296875, 49.935546875], [-27.71630859375, -36.6435546875]],
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[[356.654296875, 368.400390625], [6.41015625, 9.8505859375], [-10.53759765625, -16.02978515625]],
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[[333.80712890625, 324.25146484375], [4.69189453125, 13.3994140625], [-4.697265625, -13.39892578125]],
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[[326.76416015625, 283.53857421875], [0, 13.74267578125], [0, -25.42431640625]],
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[[352.18798828125, 219.634765625], [-16.95263671875, 17.17822265625], [16.94775390625, -17.1787109375]],
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[[415.0615234375, 193.8671875], [-24.96826171875, 0], [25.19287109375, 0]],
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[[480.68310546875, 220.66552734375], [-18.552734375, -17.86572265625], [13.96826171875, 13.28662109375]],
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[[514.6962890625, 280.10302734375], [-8.70703125, -26.3369140625], [7.55859375, -25.88037109375]],
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[[546.6484375, 221.0087890625], [-13.7431640625, 13.517578125], [19.0087890625, -18.32177734375]],
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[[612.61328125, 193.5234375], [-24.9677734375, 0], [24.7373046875, 0]],
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[[675.486328125, 219.119140625], [-17.177734375, -17.06005859375], [17.1787109375, 17.06591796875]],
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[[701.2548828125, 280.10302734375], [0, -23.58837890625], [0, 20.61376953125]],
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[[686.1376953125, 344.52197265625], [10.076171875, -22.33203125], [-10.08203125, 22.33203125]],
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[[627.73046875, 432.3046875], [28.8603515625, -36.1875], [-37.5673828125, 47.412109375]],
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[[545.6171875, 549.1171875], [17.1787109375, -30.458984375], [-13.517578125, 24.0498046875]]
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]);
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heartPath.closed = true;
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heartPath.position = view.center;
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heartPath.strokeColor = null;
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heartPath.scale(1.5);
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var groupTogether = false;
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var pathLength = heartPath.length;
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var mouseDown = false;
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var boids = [];
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// Add the boids:
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for (var i = 0; i < 300; i++) {
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var position = view.center;
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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 * pathLength;
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var point = heartPath.getPointAt(length);
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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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size = view.size;
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heartPath.position = view.center;
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}
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