p5.js中图形中的粒子系统

class Particle {
  constructor(x, y) {
    this.pos = createVector(x, y);
    this.vel = createVector(random(-1, 1), random(-1, 1));
    this.acc = createVector();
    this.maxSpeed = 2;
    this.r = 4; // 粒子半径
  }

  update() {
    this.vel.add(this.acc);
    this.vel.limit(this.maxSpeed);
    this.pos.add(this.vel);
    this.acc.mult(0); // 重置加速度
  }

  applyForce(force) {
    this.acc.add(force);
  }

  show() {
    fill(255, 100);
    ellipse(this.pos.x, this.pos.y, this.r * 2);
  }
}

let particles = [];

function setup() {
  createCanvas(600, 400);
  for (let i = 0; i < 100; i++) {
    let x = random(width);
    let y = random(height);
    particles[i] = new Particle(x, y);
  }
}

function draw() {
  background(0);
  for (let particle of particles) {
    particle.update();
    particle.show();
  }
}