[Noob]I can't change the velocity of a rigid body without f*cking up it's collision

Unity Engine
1

I created a Pong game following a tutorial, and I managed to make it work, but I was left with a doubt.

The code for the ball is the following:

using UnityEngine;
using System.Collections;

public class Ball : MonoBehaviour {
	
	// Use this for initialization
	void Start () {
		rigidbody.velocity = Vector3.right;
	}

	// Update is called once per frame
	void Update () {
		rigidbody.velocity = rigidbody.velocity.normalized;
	}
	//Collision handler
	void OnCollisionEnter(Collision collision){
		//If collision takes place against left border:
		if (collision.collider.name == "borderLeft")
		{
                         //Incomplete code
		}
		//If colision takes place against right border:
		else if (collision.collider.name == "borderRight")
		{
			//Incomplete code
		}
		//If collision takes lace against either the bottom or the top border:
		else if (collision.collider.name == "borderBot" || collision.collider.name == "borderTop")
		{
			rigidbody.velocity = new Vector3(rigidbody.velocity.x, 
			                             	 -rigidbody.velocity.y,   //Velocity remains the same both in X as in Z, but it is inverted in Y
			                             	 rigidbody.velocity.z);
		}
		//If collision takes place against either the left or the right racket:
		else if (collision.collider.name == "RacketLeftPlayer"|| collision.collider.name == "RacketRightPlayer")
		{
			rigidbody.velocity = new Vector3 (-rigidbody.velocity.x,  //This time we only invert velocity in X
			                                  rigidbody.velocity.y,
			                                  rigidbody.velocity.z);
		}
	}
}

I tried to increase the ball’s speed by modifying part of the code in this way:

void Update () {
		rigidbody.velocity = rigidbody.velocity.normalized *3;
	}

It did change the ball’s speed as desired but, as a consequence, the ball stops moving as soon as it collides against the racket, instead of inverting the vector’s X component (“bouncing”), and I have no idea how.

I know I can simply reduce the size of the whole game so that speed 1 suits my desires, but I feel like I will learn more this way.

Thanks in advance for your replies! :smile:

2

To modify the speed you can do something as simple like this in your init:

private float ballSpeed = 5.0f;
 
// Use this for initialization

void Start () {
    rigidbody.velocity = Vector3.right * ballSpeed;
}

void OnCollisionEnter(Collision collision){

        //If collision takes place against left border:

        if (collision.collider.name == "leftPaddle")

        {
                        
                   	Vector3 theScale = transform.localScale;
		         theScale.x = 1;
		         transform.localScale = theScale;

        }

        //If colision takes place against right border:

        else if (collision.collider.name == "rightPaddle")

        {

           	         Vector3 theScale = transform.localScale;
		         theScale.x = -1;
		         transform.localScale = theScale;

        }
}
3

That didn’t work :confused:
The ball simply stretches whenever it hits a border. I’m not really understanding what you did there either; sorry for my ignorance, I’m kinda new.

4

Not sure if this will help you with your reflection issue but it solves many problems people run in to when trying to “bounce” objects.