// Daniel Shiffman

// http://natureofcode.com

​

// Chapter 3: Asteroids

​

class Spaceship {

  constructor() {

    // All of our regular motion stuff

    this.position = createVector(50, height / 2);

    this.velocity = createVector();

    this.acceleration = createVector();

​

    // Arbitrary damping to slow down ship

    this.damping = 0.95;

    this.topspeed = 6;

​

    // Variable for heading!

    this.heading = 0;

​

    // Size

    this.r = 16;

​

    // Are we thrusting (to color boosters)

    this.thrusting = false;

  }

​

  // Standard Euler integration

  update() {

    this.velocity.add(this.acceleration);

    this.velocity.mult(this.damping);

    this.velocity.limit(this.topspeed);

    this.position.add(this.velocity);

    this.acceleration.mult(0);

  }

​

  // Newton's law: F = M * A

  applyForce(force) {

    let f = force.copy();

    //f.div(mass); // ignoring mass right now

    this.acceleration.add(f);

  }

​

  // Turn changes angle

  turn(angle) {

    this.heading += angle;

  }

​

  // Apply a thrust force

  thrust() {

    // Offset the angle since we drew the ship vertically

    let angle = this.heading - PI / 2;

    let force = p5.Vector.fromAngle(angle);

    force.mult(0.1);

    this.applyForce(force);

    // To draw booster

    this.thrusting = true;

  }

​

  wrapEdges() {

    let buffer = this.r * 2;

    if (this.position.x > width + buffer) this.position.x = -buffer;

    else if (this.position.x < -buffer) this.position.x = width + buffer;

    if (this.position.y > height + buffer) this.position.y = -buffer;

    else if (this.position.y < -buffer) this.position.y = height + buffer;

  }

​

  // Draw the ship

  show() {

    stroke(0);

    strokeWeight(2);

    push();

    translate(this.position.x, this.position.y + this.r);

    rotate(this.heading);

    fill(175);

    if (this.thrusting) fill(255, 0, 0);

    // Booster rockets

    rectMode(CENTER);

    rect(-this.r / 2, this.r, this.r / 3, this.r / 2);

    rect(this.r / 2, this.r, this.r / 3, this.r / 2);

    fill(175);

    // A triangle

    beginShape();

    vertex(-this.r, this.r);

    vertex(0, -this.r);

    vertex(this.r, this.r);

    endShape(CLOSE);

    rectMode(CENTER);

    pop();

​

    this.thrusting = false;

  }

}

​