// The Nature of Code

// The Coding Train / Daniel Shiffman

// https://youtu.be/ujsR2vcJlLk

// https://thecodingtrain.com/learning/nature-of-code/5.5-wander.html

​

// Main: https://editor.p5js.org/codingtrain/sketches/LVtVlS52Q

// With Sliders: https://editor.p5js.org/codingtrain/sketches/uxemh7FGc

// Deleting Positions: https://editor.p5js.org/codingtrain/sketches/EWHjy--Os

// 3D: https://editor.p5js.org/codingtrain/sketches/t6sFXmVrk

// Displacement: https://editor.p5js.org/codingtrain/sketches/VdHUvgHkm

// Perlin Noise: https://editor.p5js.org/codingtrain/sketches/XH2DtikuI

​

class Vehicle {

  constructor(x, y) {

    this.pos = createVector(x, y);

    this.vel = createVector(1, 0);

    this.acc = createVector(0, 0);

    this.maxSpeed = 4;

    this.maxForce = 0.2;

    this.r = 16;

​

    this.wanderTheta = PI / 2;

    this.wanderDistance = 100;

    this.wanderRadius = 50;

​

    this.wanderPoint = this.vel.copy().setMag(this.wanderDistance);

    this.wanderPoint.add(this.pos);

​

    this.target = this.wanderPoint.copy();

    this.target.add(this.wanderRadius, 0);

​

    this.currentPath = [];

    this.paths = [this.currentPath];

  }

​

  wander() {

    // Move wander point

    this.wanderPoint = this.vel.copy().setMag(this.wanderDistance);

    this.wanderPoint.add(this.pos);

​

    // Move target

    let offset = 32;

    let vOffset = p5.Vector.random2D().setMag(offset * 0.2);

    this.target.add(vOffset);

​

    let v = p5.Vector.sub(this.target, this.wanderPoint);

    v.setMag(this.wanderRadius);

    this.target = p5.Vector.add(this.wanderPoint, v);

​

    let center = this.wanderPoint.copy();

    stroke(255);

    noFill();

    circle(center.x, center.y, this.wanderRadius * 2);

    stroke(255);

    line(this.pos.x, this.pos.y, center.x, center.y);

​

    stroke(0, 255, 0);

    fill(0, 255, 0, 100);

    circle(this.target.x, this.target.y, offset);

    fill(0, 255, 0);

    circle(this.target.x, this.target.y, 8);

​

    stroke(255);

    line(this.pos.x, this.pos.y, this.target.x, this.target.y);

​

    noStroke();

    fill(255, 0, 0);

    circle(center.x, center.y, 8);

​

    let force = p5.Vector.sub(this.target, this.pos);

    force.setMag(this.maxForce);

    this.applyForce(force);

​

    //noLoop();

  }

​

  evade(vehicle) {

    let pursuit = this.pursue(vehicle);

    pursuit.mult(-1);

    return pursuit;

  }

​

  pursue(vehicle) {

    let target = vehicle.pos.copy();

    let prediction = vehicle.vel.copy();

    prediction.mult(10);

    target.add(prediction);

    fill(0, 255, 0);

    circle(target.x, target.y, 16);

    return this.seek(target);

  }

​

  arrive(target) {

    // 2nd argument true enables the arrival behavior

    return this.seek(target, true);

  }

​

  flee(target) {

    return this.seek(target).mult(-1);

  }

​

  seek(target, arrival = false) {

    let force = p5.Vector.sub(target, this.pos);

    let desiredSpeed = this.maxSpeed;

    if (arrival) {

      let slowRadius = 100;

      let distance = force.mag();

      if (distance < slowRadius) {

        desiredSpeed = map(distance, 0, slowRadius, 0, this.maxSpeed);

      }

    }

    force.setMag(desiredSpeed);

    force.sub(this.vel);

    force.limit(this.maxForce);

    return force;

  }

​

  applyForce(force) {

    this.acc.add(force);

  }

​

  update() {

    this.vel.add(this.acc);

    this.vel.limit(this.maxSpeed);

    this.pos.add(this.vel);

    this.acc.set(0, 0);

​

    this.currentPath.push(this.pos.copy());

    // Count positions

    let total = 0;

    for (let path of this.paths) {

      total += path.length;

    }

​

    if (total > 200 || (total > 10 && millis() > 3000)) {

      this.paths[0].shift();

      if (this.paths[0].length === 0) {

        this.paths.shift();

      }

    }

  }

​

  show() {

    stroke(255);

    strokeWeight(2);

    fill(255);

    push();

    translate(this.pos.x, this.pos.y);

    rotate(this.vel.heading());

    triangle(-this.r, -this.r / 2, -this.r, this.r / 2, this.r, 0);

    pop();

​

    for (let path of this.paths) {

      beginShape();

      noFill();

      for (let v of path) {

        vertex(v.x, v.y);

      }

      endShape();

    }

  }

​

  edges() {

    let hitEdge = false;

    if (this.pos.x > width + this.r) {

      this.pos.x = -this.r;

      hitEdge = true;

    } else if (this.pos.x < -this.r) {

      this.pos.x = width + this.r;

      hitEdge = true;

    }

    if (this.pos.y > height + this.r) {

      this.pos.y = -this.r;

      hitEdge = true;

    } else if (this.pos.y < -this.r) {

      this.pos.y = height + this.r;

      hitEdge = true;

    }

​

    if (hitEdge) {

      this.currentPath = [];

      this.paths.push(this.currentPath);

    }

  }

}

​

class Target extends Vehicle {

  constructor(x, y) {

    super(x, y);

    this.vel = p5.Vector.random2D();

    this.vel.mult(5);

  }

​

  show() {

    stroke(255);

    strokeWeight(2);

    fill("#F063A4");

    push();

    translate(this.pos.x, this.pos.y);

    circle(0, 0, this.r * 2);

    pop();

  }

}

​