Rain Drops

let vecLocation = []; 

let vecVelocity = [];

const NUM = 100;//定数

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  frameRate(60); //１秒間に何回か

  for(let i = 0; i < NUM; i++){

    vecLocation[i] = createVector(width/2, height/2);

    vecVelocity[i] = createVector(random(-10, 10), random(-10, 10));

}

  }

​

function draw() {

  background(255);

  noStroke();

  for(let i = 0; i < NUM; i++){

    ellipse(vecLocation[i].x, vecLocation[i].y, random(10, 50), random(10, 50));

    fill(random(100), random(255), random(255),127);

    vecLocation[i].add(vecVelocity[i]);

    if(vecLocation[i].x > width || vecLocation[i].x < 0){ 

      vecVelocity[i].x = vecVelocity[i].x * -1;

    }

    if(vecLocation[i].y > height || vecLocation[i].y < 0){

      vecVelocity[i].y = vecVelocity[i].y * -1;

    }

  }

}