// http://codingtra.in

// https://youtu.be/CKeyIbT3vXI

​

class Particle {

  constructor(x, y, hu, firework) {

    this.pos = createVector(x, y);

    this.firework = firework;

    this.lifespan = 200;

    this.hu = hu;

    this.acc = createVector(0, 0);

    if (this.firework) {

      this.vel = createVector(0, random(-10, -20));

    } else {

      // this.vel = p5.Vector.random2D();

      // this.vel.mult(random(2, 10));

​

      // //normal ring

      // this.vel = p5.Vector.random2D().mult(10);;

​

      // //normal firework

      // this.vel = p5.Vector.random2D().mult(random(4, 10)).mult(4);

​

      // // dubble ring

      // this.vel = p5.Vector.random2D();

      // if (random(1) < 0.5) {

      //     this.vel.mult(random(20, 20));

      // } else {

      //     this.vel.mult(random(10, 10) * 4 + 3);

      // }

​

​

      // // oval shape

      // let rotAngle = 0// -PI / 8; // (-PI/2 ~ PI/2)

      // let a = random(TWO_PI);

      // let m = 5, n = 10;

      // let velX = cos(a) * m * n / sqrt(pow(m * sin(a), 2) + pow(n * cos(a), 2));

      // let velY = sin(a) * m * n / sqrt(pow(m * sin(a), 2) + pow(n * cos(a), 2));

​

      // velX = (velX * cos(rotAngle) - velY * sin(rotAngle)) * 10;

      // velY = (velX * sin(rotAngle) + velY * cos(rotAngle)) * 10;

​

      // this.vel = createVector(velX, velY);//.mult(10);

​

      // // heart shape

      // let a = random(TWO_PI);

​

      // // let tempVel = p5.Vector.fromAngle(angle, 1);

      // let velX = 16 * pow(sin(a), 3);

      // let velY = -1 * (13 * cos(a) - 5 * cos(2 * a) - 2 * cos(3 * a) - cos(4 * a));

​

      // this.vel = createVector(velX, velY);

​

​

      // four-leave roses 

      let a = random(TWO_PI);

      let leaveN = 4;

      let velX = cos(leaveN / 2 * a) * cos(a) * 10;

      let velY = cos(leaveN / 2 * a) * sin(a) * 10;

​

      this.vel = createVector(velX, velY);

​

    }

  }

​

  applyForce(force) {

    let airforce = this.vel.copy().normalize().mult(this.vel.magSq() * (-0.005));

    this.acc.add(airforce);

    this.acc.add(gravity);

  }

​

  update() {

    if (!this.firework) {

      this.vel.mult(0.9);

      this.lifespan -= 4;

    }

    this.vel.add(this.acc);

    this.pos.add(this.vel);

    this.acc.mult(0);

  }

​

  done() {

    if (this.lifespan < 0) {

      return true;

    } else {

      return false;

    }

  }

​

  show() {

    colorMode(HSB);

​

    if (!this.firework) {

      strokeWeight(2);

      stroke(this.hu, 255, 255, this.lifespan);

    } else {

      strokeWeight(4);

      stroke(this.hu, 255, 255);

    }

​

    point(this.pos.x, this.pos.y);

  }

}