silentscorpion / volleyball-ai

I recently worked on a 2D Volleyball game and developed a fairly decent AI for it. Here's the source code.

VolleyBall-AI

I recently worked on a 2D Volleyball game and developed a fairly decent AI for it. Here's the source code.

There're 3 scripts

1. Player.cs
2. AIBehaviour.cs
3. BallBehaviour.cs

3 Rigidbodies in the scene for the Player, the ball and the AI bot

The sprites setup is shown in the figure below:

I've created a simple State Machine for the AI volleyball player. This state machine has 4 states represented by 4 coroutines...

1. Wait() - When the ball is on the Player's side, then simply wait for the ball to be hit.
2. Serve() - The ball is on the AI's side, and so get ready to jump and volley.
3. Jump() - When the ball is within the range of the Ai bot, then simply jump
4. MoveTowardsPrediction() - predict where the ball will land and simply move towards that position

``

    private void FixedUpdate() {
    grounded = Physics2D.OverlapCircle(groundChecker.transform.position, groundCheckRadius, whatIsGround);

    if (GameController.playStarted && !BallBehaviour.connected) {           
        //Wait
        if (ball.transform.position.x < 0 && ballRigidbody.gravityScale == 0) {
            StartCoroutine(Wait());
        }
        //My serve
        else if (ball.transform.position.x > 0 && ballRigidbody.gravityScale == 0) {
            StartCoroutine(Serve());
        }
        //Jump
        else if (Mathf.Abs(ball.transform.position.x - transform.position.x) < 5 &&  Mathf.Abs(ball.transform.position.y - transform.position.y) < Random.Range(4,5) && Time.time > 0.3f + nextChangeTime) {
            //Jump every 0.3 seconds
            nextChangeTime = 0.3f + Time.time;
            StartCoroutine(Jump());
        }
        else if (Mathf.Abs(ball.transform.position.x - transform.position.x) < 5 && Mathf.Abs(ball.transform.position.x - transform.position.x) > 3 && Time.time > 0.3f + nextChangeTime) {
            //Jump every 0.3 seconds
            nextChangeTime = 0.3f + Time.time;
            StartCoroutine(Jump1());
        }

        //Move towards the predicted position
        if (Mathf.Sign(BallBehaviour.predictedPoint.x) == Mathf.Sign(transform.position.x) && BallBehaviour.impactPos.x > 0 && ballRigidbody.velocity.x < 10f && ballRigidbody.gravityScale != 0) {
            StartCoroutine(MoveTowardsPrediction(BallBehaviour.predictedPoint));
        }
        else if (Mathf.Sign(BallBehaviour.predictedPoint.x) == Mathf.Sign(transform.position.x)  && BallBehaviour.impactPos.x > 0 && ballRigidbody.velocity.x > 10f && BallBehaviour.predictedPoint.x > center.transform.position.x && ballRigidbody.gravityScale != 0) {
            BallBehaviour.predictedPoint.x = 8.87f - BallBehaviour.predictedPoint.x;
            StartCoroutine(MoveTowardsPrediction(BallBehaviour.predictedPoint));
        }
    }
}

On Collision With the player, the ball will be hit with a much random direction

private void OnCollisionEnter2D(Collision2D collision) {
    //Apply force to the ball so that it moves in the proper direction when hit by the player Controller
    if (collision.collider.CompareTag("Ball")) {
        ball.GetComponent<AudioSource>().Play();
        ballRigidbody.isKinematic = false;
        valueGiven = false;
        Vector2 diff = (ballRigidbody.transform.position - transform.position).normalized;
        //Ball is on the right
        if (diff.x >= 0) {
            //Find direction
            Vector2 difference = ball.transform.position - transform.position;
            float angle = Vector2.Angle(Vector2.right, difference);
            float randomAngle = Random.Range(angle, 90 - angle);
            Vector3 dir = Quaternion.AngleAxis(randomAngle, Vector3.forward) * Vector3.right;
            ballRigidbody.velocity = dir * ballForce;
        }
        else if (diff.x < 0) {
            Vector2 difference = ball.transform.position - transform.position;
            float angle = Vector2.Angle(Vector2.right, difference);
            float randomAngle = Random.Range(angle - 15, angle+ 15);
            //  print(randomAngle);
            Vector3 dir = Quaternion.AngleAxis(randomAngle, Vector3.forward) * Vector3.right;
            //rigidBody.AddForce(dir * ballForce);
            ballRigidbody.velocity = dir * ballForce;
        }
    }
}