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smukkejohan/fishflocking.pde

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Last active August 29, 2015 13:56
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Example of Flocking - Illutron - Nikola Lenivets
Raw
fishflocking.pde
/**
* Flocking
* by Daniel Shiffman.
*
* An implementation of Craig Reynold's Boids program to simulate
* the flocking behavior of birds. Each boid steers itself based on
* rules of avoidance, alignment, and coherence.
*
* Click the mouse to add a new boid.
*/
Flock flock;
void setup() {
size(960, 600);
flock = new Flock();
// Add an initial set of boids into the system
for (int i = 0; i < 30; i++) {
flock.addBoid(new Boid(width/2,height/2));
}
}
void draw() {
background(2,2,20);
flock.run();
}
// Add a new boid into the System
void mousePressed() {
flock.addBoid(new Boid(mouseX,mouseY));
}
// The Boid class
class Boid {
PVector location;
PVector velocity;
PVector acceleration;
float r;
float maxforce; // Maximum steering force
float maxspeed; // Maximum speed
Boid(float x, float y) {
acceleration = new PVector(0, 0);
// This is a new PVector method not yet implemented in JS
// velocity = PVector.random2D();
// Leaving the code temporarily this way so that this example runs in JS
float angle = random(TWO_PI);
velocity = new PVector(cos(angle), sin(angle));
location = new PVector(x, y);
r = 2.0;
maxspeed = 2;
maxforce = 0.03;
}
void run(ArrayList<Boid> boids) {
flock(boids);
update();
borders();
render();
}
void applyForce(PVector force) {
// We could add mass here if we want A = F / M
acceleration.add(force);
}
// We accumulate a new acceleration each time based on three rules
void flock(ArrayList<Boid> boids) {
PVector sep = separate(boids); // Separation
PVector ali = align(boids); // Alignment
PVector coh = cohesion(boids); // Cohesion
// Arbitrarily weight these forces
sep.mult(1.5);
ali.mult(1.0);
coh.mult(1.0);
// Add the force vectors to acceleration
applyForce(sep);
applyForce(ali);
applyForce(coh);
}
// Method to update location
void update() {
// Update velocity
velocity.add(acceleration);
// Limit speed
velocity.limit(maxspeed);
location.add(velocity);
// Reset accelertion to 0 each cycle
acceleration.mult(0);
}
// A method that calculates and applies a steering force towards a target
// STEER = DESIRED MINUS VELOCITY
PVector seek(PVector target) {
PVector desired = PVector.sub(target, location); // A vector pointing from the location to the target
// Scale to maximum speed
desired.normalize();
desired.mult(maxspeed);
// Above two lines of code below could be condensed with new PVector setMag() method
// Not using this method until Processing.js catches up
// desired.setMag(maxspeed);
// Steering = Desired minus Velocity
PVector steer = PVector.sub(desired, velocity);
steer.limit(maxforce); // Limit to maximum steering force
return steer;
}
void render() {
// Draw a triangle rotated in the direction of velocity
float theta = velocity.heading2D() + radians(90);
// heading2D() above is now heading() but leaving old syntax until Processing.js catches up
fill(200, 100);
stroke(255);
pushMatrix();
translate(location.x, location.y);
rotate(theta);
beginShape(TRIANGLES);
vertex(0, -r*2);
vertex(-r, r*2);
vertex(r, r*2);
endShape();
fill(200,0,0, 40);
stroke(10,20);
ellipse(0,0,60,60);
popMatrix();
}
// Wraparound
void borders() {
if (location.x < -r) location.x = width+r;
if (location.y < -r) location.y = height+r;
if (location.x > width+r) location.x = -r;
if (location.y > height+r) location.y = -r;
}
// Separation
// Method checks for nearby boids and steers away
PVector separate (ArrayList<Boid> boids) {
float desiredseparation = 25.0f;
PVector steer = new PVector(0, 0, 0);
int count = 0;
// For every boid in the system, check if it's too close
for (Boid other : boids) {
float d = PVector.dist(location, other.location);
// If the distance is greater than 0 and less than an arbitrary amount (0 when you are yourself)
if ((d > 0) && (d < desiredseparation)) {
// Calculate vector pointing away from neighbor
PVector diff = PVector.sub(location, other.location);
diff.normalize();
diff.div(d); // Weight by distance
steer.add(diff);
count++; // Keep track of how many
}
}
// Average -- divide by how many
if (count > 0) {
steer.div((float)count);
}
// As long as the vector is greater than 0
if (steer.mag() > 0) {
// First two lines of code below could be condensed with new PVector setMag() method
// Not using this method until Processing.js catches up
// steer.setMag(maxspeed);
// Implement Reynolds: Steering = Desired - Velocity
steer.normalize();
steer.mult(maxspeed);
steer.sub(velocity);
steer.limit(maxforce);
}
return steer;
}
// Alignment
// For every nearby boid in the system, calculate the average velocity
PVector align (ArrayList<Boid> boids) {
float neighbordist = 50;
PVector sum = new PVector(0, 0);
int count = 0;
for (Boid other : boids) {
float d = PVector.dist(location, other.location);
if ((d > 0) && (d < neighbordist)) {
sum.add(other.velocity);
count++;
}
}
if (count > 0) {
sum.div((float)count);
// First two lines of code below could be condensed with new PVector setMag() method
// Not using this method until Processing.js catches up
// sum.setMag(maxspeed);
// Implement Reynolds: Steering = Desired - Velocity
sum.normalize();
sum.mult(maxspeed);
PVector steer = PVector.sub(sum, velocity);
steer.limit(maxforce);
return steer;
}
else {
return new PVector(0, 0);
}
}
// Cohesion
// For the average location (i.e. center) of all nearby boids, calculate steering vector towards that location
PVector cohesion (ArrayList<Boid> boids) {
float neighbordist = 50;
PVector sum = new PVector(0, 0); // Start with empty vector to accumulate all locations
int count = 0;
for (Boid other : boids) {
float d = PVector.dist(location, other.location);
if ((d > 0) && (d < neighbordist)) {
sum.add(other.location); // Add location
count++;
}
}
if (count > 0) {
sum.div(count);
return seek(sum); // Steer towards the location
}
else {
return new PVector(0, 0);
}
}
}
// The Flock (a list of Boid objects)
class Flock {
ArrayList<Boid> boids; // An ArrayList for all the boids
Flock() {
boids = new ArrayList<Boid>(); // Initialize the ArrayList
}
void run() {
for (Boid b : boids) {
b.run(boids); // Passing the entire list of boids to each boid individually
}
}
void addBoid(Boid b) {
boids.add(b);
}
}
Raw
index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Programming Media I</title>
<meta name="description" content="">
</head>
<body>
<div>
<canvas id="sketch" data-processing-sources="fishflocking.pde"
width="960" height="600">
<p>Your browser does not support the canvas tag.</p>
<!-- Note: you can put any alternative content here. -->
</canvas>
</div>
<script type="text/javascript" src="http://classes.dma.ucla.edu/Fall13/252A/js/vendor/processing.js"></script>
</body>
</html>
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