CODEWITHSUNDEEP
c#unity-game-engine
David Marsh
David Marsh

Reputation: 147

Ball slows down in unity2D game

I have a blockbreaker type game coded using C# that mainly works fine but upon play testing i have found the ball will slow right down in certain situations! i.e if it wedges between to game object bricks the force of the ball rapidly slows down! 8 times out of ten this will not happen but other times it does and im unsure why! i will post the Ball script i think you will need to help solve this but should you need anymore information then please ask.

public class Ball : MonoBehaviour {

private Paddle paddle;

private bool hasStarted = false;

private Vector3 paddleToBallVector;

void Start () {
    paddle = GameObject.FindObjectOfType<Paddle> ();
    paddleToBallVector = this.transform.position - paddle.transform.position;
}

// Update is called once per frame
void Update () {
    if (!hasStarted) {
        //lock ball relative to the paddle
        this.transform.position = paddle.transform.position + paddleToBallVector;
        //wait for mouse press to start

        if (Input.GetMouseButtonDown (0)) {
        //if (Input.GetTouch(0).phase == TouchPhase.Ended){
        hasStarted = true;
            this.GetComponent<Rigidbody2D> ().velocity = new Vector2 (2f, 10f);
        }
    }
}

void OnCollisionEnter2D(Collision2D collision){

    Vector2 tweak = new Vector2 (Random.Range(0f,0.2f),Random.Range(0f,0.2f));

    if (hasStarted) {
        GetComponent<AudioSource> ().Play ();
        GetComponent<Rigidbody2D>().velocity += tweak;
    }
}

}

Upvotes: 1

Views: 984

Answers (1)

CMilby
CMilby

Reputation: 644

You are adding directly to the velocity of the ball. The velocity variable defines a direction and speed, not just a speed as you are thinking here.

So, when the ball collides with a block it has a velocity of (+x, +y). After the collision and bounce is has a velocity of (+x, -y). So by adding a random positive value to the velocity when it has the -y velocity means that it will slow down the ball.

This does not happen every time because you are moving the ball in your Update() method. Change that to 'FixedUpdated()'. Fixed Update handles all physics calculations.

Also, I would recommend having a RigidBody2D on your Ball object. Moving physics objects should always have RigidBodies. With this, you can then use AddForce in the forward direction of your ball and that should solve your problem.

EDIT: I see you have a RigidBody2D already. I missed that the first time. Instead of having GetComponent<RigidBody2D>().velocity try GetComponent<RigidBody2D>().AddForce( transform.forward * impulseAmount, ForceMode.Impluse );

Upvotes: 2

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