Bouncing ball - OpenProcessing

mySketch
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var x
var y
var xv
var yv
var speed = 10
var d = 30
var test
var bg = true
function setup() {
  createCanvas(windowWidth, windowHeight);
  background(100);
  x = width/2
  y = height/2
  xv = random(speed * -1 +1,speed)
  yv = speed - abs(xv)
  if (round(random(0,1)) == 0){
    yv = yv
  }else{
    yv = yv * -1
  }
}
​
function draw() {
  if(bg){
  background(255)
  }
  fill(0,0,255)
  move()
  collide()
  circle(x,y,d)
}
function move(){
  x += xv
  y += yv
}
function collide(){
  //collideRectCircle(x1, y1, width1, height1, cx, cy, diameter)
  if(collideRectCircle(0,-35,width,35,x,y,d)){ //top
    yv = abs(yv)
  }
  if(collideRectCircle(0,height,width,35,x,y,d)){ //bottom
    yv = abs(yv) * -1
  }
  if(collideRectCircle(-35,0,35,height,x,y,d)){ //left
    xv = abs(xv)
  }
  if(collideRectCircle(width,0,35,height,x,y,d)){ //right
    xv = abs(xv) * -1
  }
}
function keyPressed(){
  if(key == 'b'){
    if(bg){
      bg = false
    }else{
      bg = true
    }
  }
}