Create a ball object that bounces off of the side and top walls.

​

Moving past the bottom wall will cause loss of turn

​

The ball can also collide with either a brick or the paddle, in which case the ball will move in the opposite y direction.

​

The ball is represented by an ellipse.  It starts in the center of the screen with a given yvelocity and an random xvelocity

*/

​

class Ball {

  constructor() {

    this.x = width / 2;

    this.y = height / 2 + 30;

    this.r = 30;

    this.yVel = 3;

    this.xVel = random(1, 3);

    let flipDirX = random();

    if (flipDirX < 0.5) {

      this.xVel = -this.xVel;

    }

    this.xSpeed = 1;

    this.ySpeed = 1;

  }

​

  display() {

    fill("black");

    ellipse(this.x, this.y, this.r);

  }

​

  move() {

    this.x += this.xVel * this.xSpeed;

    this.y += this.yVel * this.ySpeed;

  }

​

  checkForWalls() {

    if (this.x + this.r > width) {

      this.xSpeed *= -1;

    } else if (this.y < this.r) {

      this.ySpeed *= -1;

    } else if (this.x < this.r) {

      this.xSpeed *= -1;

    }

  }

​

  intersectBall(obj) {

​

    // temporary variables to set edges for testing

    let testX = this.x;

    let testY = this.y;

​

    // which edge is closest?

    if (this.x < obj.x) testX = obj; // test left edge

    else if (this.x > obj.x + obj.w) testX = obj.x + obj.w; // right edge

    if (this.y < obj.y) testY = obj.y; // top edge

    else if (this.y > obj.y + obj.h) testY = obj.y + obj.h; // bottom edge

​

    // get distance from closest edges

    let distX = this.x - testX;

    let distY = this.y - testY;

    let distance = sqrt((distX * distX) + (distY * distY));

​

    // if the distance is less than the radius, collision!

    if (distance <= this.r) {

      return true;

    }

    return false;

  }

​

  // return ((this.x > paddle.x && this.x < paddle.x + paddle.w) && (this.y > paddle.y && this.y < paddle.y + paddle.h) )

  // return true for left edge,

  // false for right edge

  isNearLeftEdgeOfPaddle(paddle) {

​

    // which edge is closest?

    if (this.x < paddle.x) {

      return true;

    } else if (this.x > paddle.x + paddle.w) {

      return false;

    }

  }

​

  intersectPaddle(obj) {

​

    // temporary variables to set edges for testing

    let testX = this.x;

    let testY = this.y;

​

    // which edge is closest?

    if (this.x < obj.x) {

      testX = obj; // test left edge

    } else if (this.x > obj.x + obj.w) {

      testX = obj.x + obj.w; // right edge

    }

    if (this.y < obj.y) testY = obj.y; // top edge

    else if (this.y > obj.y + obj.h) testY = obj.y + obj.h; // bottom edge

​

    // get distance from closest edges

    let distX = this.x - testX;

    let distY = this.y - testY;

    let distance = sqrt((distX * distX) + (distY * distY));

​

    // if the distance is less than the radius, collision!

    if (distance <= this.r) {

      return true;

    }

    return false;

  }

​

  // return ((this.x > paddle.x && this.x < paddle.x + paddle.w) && (this.y > paddle.y && this.y < paddle.y + paddle.h) )

​

​

​

  bounceOffObj() {

    this.ySpeed *= -1;

  }

​

  moveOffScreen() {

    this.x = width + 50;

    this.y = 200;

  }

​

  isOffScreen() {

    return (this.y > height + this.r)

  }

​

  reset() {

    this.x = width / 2;

    this.y = height / 2 + 30

    this.yVel = 0;

    this.xVel = 0;

​

  }

​

  startMoving() {

    this.yVel = 3;

    this.xVel = random(1, 3);

    let flipDirX = random();

    if (flipDirX < 0.5) {

      this.xVel = -this.xVel;

    }

  }

​

}