Simulación física de lluvia en P5JS

Rain.js

"use strict"
var system;
var line_system;
var gravity;
var wind;

function setup() {
  createCanvas(720, 900);
  system = new ParticleSystem(createVector(width/2, -40));
  line_system = new LineSystem();
  gravity = createVector(0, 0.05);
  wind = createVector(random(-0.05,0.05), 0);
}

function draw() {
  background(51);
  system.addParticle(1);
  system.run();
  line_system.run();
  drawControls();
  //print(system.particles.length);
}

class Particle  {
  constructor(position, velocity,splash){
    this.acceleration = createVector(0, 0);
    this.velocity = velocity;
    this.position = position.copy();
    this.lifespan = 255.0;
    this.mass = random(1.,3.);
    this.splash = splash;
    this.dead = false;
  };

  run(){
  this.update();
  this.display();
  };

  update(){
  this.velocity.add(this.acceleration);
  this.position.add(this.velocity);
  this.lifespan -= 2;
  };
  
  applyForce(force){
    let f = p5.Vector.div(force, this.mass);
    this.acceleration.add(f);
  };
  
  kill(){
    this.dead =true;
  }

  display(){
  stroke(200, this.lifespan);
  strokeWeight(this.mass);
  line(this.position.x, this.position.y, this.position.x+this.velocity.x, this.position.y+this.velocity.y);
  };

// Determina si está fuera de pantalla
  isDead(){
  if (this.position.y > height | this.dead) {
    return true;
  } else {
    return false;
  }
  };
}

class ParticleSystem {
  constructor(position) {
  this.origin = position.copy();
  this.particles = [];
  };

  addParticle(number) {
    for (let j = 0; j<=number; j++) {
    this.particles.push(new Particle(createVector(random(-width/2,1.5*width), random(this.origin.y-40,this.origin.y+40)),createVector(0, random(1,4)),false));
    }
  };
  addSplash(number,position,velocity){
    for (let j = 0; j<=number; j++) {
    let s = new Particle(position, createVector(velocity.x*0.4, velocity.y*0.4),true);
    s.mass = 1;
    this.particles.push(s);
    }
  }

  run() {
  for (var i = this.particles.length-1; i >= 0; i--) {
    var p = this.particles[i];
    p.applyForce(gravity);
    p.applyForce(wind);
    p.run();
    
    if (p.isDead()) {
      this.particles.splice(i, 1);
    }
  }
};
}

class Line {
  constructor() {
  this.origin = createVector(mouseX, mouseY);
  this.end = null;
  this.ready = false;
  line_system.lines.push(this);
  print("nueva linea");
  };
  ending(){
    this.end = createVector(mouseX, mouseY);
    print("linea terminada");
    
  }
  display(){
    if (this.end!=null){
      stroke("white");
      strokeWeight(3);
      line(this.origin.x,this.origin.y,this.end.x,this.end.y);
      this.ready = true;
    }
    else if (!this.ready) {
      stroke("black");
      strokeWeight(1);
      line(this.origin.x,this.origin.y,mouseX,mouseY);
    }
  }
}

class LineSystem {
  constructor(){
    this.lines = [];
    this.f_coeff = 1.5;
  }
  run(){
    this.display();
    this.collitions();
  }
  addLine(){
    let l = new Line();
  }
  endLine(){
    line_system.lines[this.lines.length-1].ending();
  }
  deleteAll(){
    this.lines.splice(0, this.lines.length);
  }
  display(){
    for (var i = 0; i<this.lines.length; i++) {
      this.lines[i].display();
    }
  }
  collitions(){
    for (let i = 0; i<this.lines.length; i++) {
      for (let j = 0; j<system.particles.length; j++) {
        if (system.particles[j].splash==true){
          system.particles[j].kill();
        }
        else if(this.lines[i].ready && collideLineLine(this.lines[i].origin.x,this.lines[i].origin.y,this.lines[i].end.x,this.lines[i].end.y,system.particles[j].position.x,system.particles[j].position.y,system.particles[j].position.x+system.particles[j].velocity.x,system.particles[j].position.y+system.particles[j].velocity.y)){
          let friction = system.particles[j].velocity.mult(-1).normalize().mult(this.f_coeff);
          system.particles[j].applyForce(friction);
          //system.particles[j].velocity = p5.Vector.mult(system.particles[j].velocity, -0.5);
          let splashes = random(1,3);
          //system.particles[j].mass *= 1/splashes; //quita masa a la gota original
          system.addSplash(splashes,system.particles[j].position,system.particles[j].velocity); //crea pequeñas gotas que salpican
        }
      }
    }
  }

}

function mousePressed() {
  if (mouseButton == LEFT){
    line_system.addLine();
  }
  
}
function mouseReleased() {
  if (mouseButton == LEFT){
    line_system.endLine();
  }
  else if (mouseButton == RIGHT){
    line_system.deleteAll();
  }
}
function keyPressed(){
  if (keyCode== CONTROL){
    line_system.deleteAll();
  }
}
function drawControls(){
  let controls="RIGHT CLICK->Draw line      CTRL ->Erase all";
  textSize(11);
  fill("white");
  noStroke();
  text(controls,20,880);
}