// Daniel Shiffman

// https://thecodingtrain.com/CodingChallenges/124-flocking-boids.html

// https://youtu.be/mhjuuHl6qHM

​

//Looks great in fullscreen mode.

​

class Boid {

    constructor() {

        this.position = createVector(random(width), random(height), random(depth));

        this.velocity = p5.Vector.random3D();

        this.velocity.setMag(random(2, 4));

        this.acceleration = createVector();

        this.maxForce = 0.2;

        this.maxSpeed = 10;

        this.color = {r : random(10, 255), g : random(10, 255), b : random(10, 255)};

​

        this.x = [],

        this.y = [],

        this.segNum = 20,

        this.segLength = 4;

​

        for (var i = 0; i < this.segNum; i++) {

            this.x[i] = 0;

            this.y[i] = 0;

        }

    }

​

    edges() {

        if (this.position.x < 0 || this.position.x > width)

            this.velocity.x = 0 - this.velocity.x;

        if (this.position.y < 0 || this.position.y > height)

            this.velocity.y = 0 - this.velocity.y;

        if (this.position.z < 1 || this.position.z > depth)

            this.velocity.z = 0 - this.velocity.z;

        return;

        if (this.position.x > width) {

            this.position.x = 0;

        } else if (this.position.x < 0) {

            this.position.x = width;

        }

        if (this.position.y > height) {

            this.position.y = 0;

        } else if (this.position.y < 0) {

            this.position.y = height;

        }

    }

​

    work(boids, perception) {

        let align = createVector();

        let cohesion = createVector();

        let separation = createVector();

        let total = 0;

        for (let other of boids) {

            if (other != this) {

                let d = dist(this.position.x, this.position.y, other.position.x, other.position.y);

                if (d < perception) {

                    align.add(other.velocity);

​

                    cohesion.add(other.position);

​

                    let diff = p5.Vector.sub(this.position, other.position);

                    diff.div(d * d);

                    separation.add(diff);

​

​

​

                    total++;

                }

            }

        }

        if (total > 0) {

            align.div(total);

            align.setMag(this.maxSpeed);

            align.sub(this.velocity);

            align.limit(this.maxForce);

​

            cohesion.div(total);

            cohesion.sub(this.position);

            cohesion.setMag(this.maxSpeed);

            cohesion.sub(this.velocity);

            cohesion.limit(this.maxForce);

​

            separation.div(total);

            separation.setMag(this.maxSpeed);

            separation.sub(this.velocity);

            separation.limit(this.maxForce);

        }

        return {

            align: align,

            cohesion: cohesion,

            separation: separation

        };

    }

​

​

    flock(boids, perception) {

        let w = this.work(boids, perception);

        let alignment = w.align;

        let cohesion = w.cohesion;

        let separation = w.separation;

​

        alignment.mult(alignSlider.value());

        cohesion.mult(cohesionSlider.value());

        separation.mult(separationSlider.value());

​

        this.acceleration.mult(0);

        this.acceleration.add(alignment);

        this.acceleration.add(cohesion);

        this.acceleration.add(separation);

        this.acceleration.z *= 0.0001;

    }

​

    update() {

        this.position.add(this.velocity);

        this.velocity.add(this.acceleration);

        this.velocity.limit(this.maxSpeed);

    }

​

    show() {

​

        strokeWeight(this.position.z);

        this.dragSegment(0, this.position.x, this.position.y);

        for( var i= 0; i < this.x.length - 1; i++)

            this.dragSegment(i + 1, this.x[i], this.y[i]);

​

        strokeWeight(8);

        stroke(this.color.r, this.color.g, this.color.b);

        point(this.position.x, this.position.y);

    }

​

    dragSegment(i, xin, yin) {

        var dx = xin - this.x[i];

        var dy = yin - this.y[i];

        var angle = atan2(dy, dx);

        this.x[i] = xin - cos(angle) * this.segLength;

        this.y[i] = yin - sin(angle) * this.segLength;

        this.segment(this.x[i], this.y[i], angle);

      }

      segment(x, y, a) {

        push();

        translate(x, y);

        rotate(a);

        line(0, 0, this.segLength, 0);

        pop();

      }

}