ランダムde動くball - OpenProcessing

mySketch
xxxxxxxxxx
 
let num  = 100;  //円の数
let vecLocation  = [];  //円の中心の位置ベクトル
let vecVelocity  = [];  //円の速度ベクトル
let fill_col = [];
let r  = [];
let movement = [];
let movement_1 = [];
function setup()  { 
  createCanvas(windowWidth,  windowHeight);  //画面を生成
  frameRate(60);  //フレームレート
  for (let i  = 0;  i  < num;  i++)  { 
    vecLocation[i]  = createVector(width  / 2,  height  / 2); 
    vecVelocity[i]  = createVector(random(-10, 10),  random(-10, 10));
    fill_col[i] = color(random(255), random(255), random(255), random(150,255));
    r[i] = random(10, 50);
    movement_1[i] = random(10);
  }                
}
function draw() {
  background(0);  //背景を描画
  noStroke();  //枠線なし
  ball_num = random(100);
  movement_1 = random(windowHeight/random(10, 20));
  movement_2 = random(windowWidth/random(10, 50));
  //円の数だけくりかえす
  for (let i  = 0; i  < num; i++) { 
    fill(fill_col[i]);
    vecLocation[i].add(vecVelocity[i]);  //円の座標を更新
    ellipse(vecLocation[i].x, vecLocation[i].y,  r[i],  r[i]);  //指定した位置に円を描画
    if (vecLocation[i].x < 0 || vecLocation[i].x > width) { //もし画面の左端、または右端に到達したら
      vecVelocity[i].x = vecVelocity[i].x * -1;  //X方向のスピードを反転
    } 
    if (vecLocation[i].y < 0 || vecLocation[i].y > height) {  //もし画面の下端、または上端に到達したら
      vecVelocity[i].y = vecVelocity[i].y * -1;  //Y方向のスピードを反転
    }
    if (movement_1 > random(windowWidth)) { 
      vecVelocity[i].x = vecVelocity[i].x* -1;  
    } 
    if (movement_2 < random(windowWidth/100)){
      vecVelocity[i].x = vecVelocity[i].x* 1.0008;
    }else{
      vecVelocity[i].x = vecVelocity[i].x- 0.001;
    }
    if (movement_2 > random(windowHeight)) { 
      vecVelocity[i].y = vecVelocity[i].y* -1;  
    } 
    if (movement_1 < random(windowHeight/70)){
      vecVelocity[i].y = vecVelocity[i].y* 1.0004;
    }else{
      vecVelocity[i].y = vecVelocity[i].y+ 0.001;
    }
  }
}