Spark

let vecLocation=[];//位置ベクトル

let vecVelocity=[];//速度ベクトル

const NUM =50; //定数

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  frameRate(60);

  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(0); 

 noStroke();

  fill(random(1,255),random(1,255),random(1,255));

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

  ellipse(vecLocation[i].x,vecLocation[i].y,20,20);

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

  fill(random(1,255),random(1,255),random(1,255));

  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;

  }

  }

}

​