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Unity 2d player jumping infinitely

Im new to unity and this is my first game but my player is jumping infinitely and I've watched a lot of tutorials and still dont know how to fix it.
heres my code
public float moveSpeed = 5f;
void Update()
{
Jump();
Vector3 movement = new Vector3(Input.GetAxis("Horizontal"), 0f, 0f);
transform.position += movement * Time.deltaTime * moveSpeed;
Vector3 characterScale = transform.localScale;
if (Input.GetAxis("Horizontal") < 0)
{
characterScale.x = 1;
}
if (Input.GetAxis("Horizontal") > 0)
{
characterScale.x = -1;
}
transform.localScale = characterScale;
}
void Jump()
{
if (Input.GetButtonDown("Jump"))
{
gameObject.GetComponent<Rigidbody2D>().AddForce(new Vector2(0f, 15f), ForceMode2D.Impulse);
}
}
}

There are a couple of things you have there. First you have Input.GetButtonDown("Jump") This means while the player is holding the button down it will execute that script inside the if statement, which applies a force. So this will run every frame and every frame while the player is holding down the button it will apply that force. You can try to do Input.GetButtonUp("Jump") which will be true when the player lets go of the button, then it will apply that force. Now you can keep the GetButtonDown its no problem if thats the feel you are going foor.
But the real problem and the second this is, you need to check if the player is touching the ground or not. If he is touching the ground then you can apply that force. If he is not touching the ground then dont apply the force.
There are couple of ways to go about this, the easiest way is to create a new Layer and call it Ground or something.
You click that drop down and click on Add layer .. then you can add a layer, then go back to ground gameobject and assign that layer to that. Now am assuming that the ground has a collider on it so the player doesnt go through it.
After that you need a reference to the player collider. In the Start() method you can add this:
private Collider2D myCollider;
void Start()
{
// This will get a reference to the collider 2d on the player
myCollider = GetComponent<Collider2D>();
}
void Update()
{
.
.
.
// This means the player is touching the ground layer.
if (myCollider.IsTouchingLayers(LayerMask.GetMask("Ground")))
{
if (Input.GetButtonDown("Jump"))
{
gameObject.GetComponent<Rigidbody2D>().AddForce(new Vector2(0f, 15f), ForceMode2D.Impulse);
}
}
}
So what this script does, it gets a reference to the player collider, and then checks if that player collider is touching the layer called ground. The ground needs to have a collider as well not just to prevent the player from fall through the level, but also to trigger this boolean to be true or false. True if they are touching each other, false if they are not. So, if they are not touching the ground then it doesnt matter how many times the player will press that button, he will not jump. Once they do then it applies the jump force if they are pressing Jump.

why my player rotates in unity

I attach a movement script to the player. with reference to the roller ball tutorial and modified it for jump. the problem is that when may player moves in any direction the player starts to rotate in that direction and even if i am standing still at the one position it starts to rotate and fall down the platform. the player has a rigidbody, boxcollider components.
void Awake ()
{
playerRigidbody = GetComponent<Rigidbody>();
Coll = GetComponent<CapsuleCollider>();
}
/*private void Update()
{
}*/
// Update is called once per frame
void FixedUpdate ()
{
float h = Input.GetAxisRaw("Horizontal");
float v = Input.GetAxisRaw("Vertical");
bool down = Input.GetKeyDown(KeyCode.Space);
if (down)
{
playerRigidbody.AddForce(Vector3.up * jumpForce, ForceMode.Impulse);
}
Move(h, v);
}
private bool IsGrounded()
{
return Physics.CheckCapsule(Coll.bounds.center, new Vector3(Coll.bounds.center.x,Coll.bounds.min.y,Coll.bounds.center.z),Coll.height * 9f,Ground);
}
void Move (float h, float v)
{
movement.Set(h, 0f, v);
movement = movement.normalized * speed * Time.deltaTime;
playerRigidbody.MovePosition(transform.position + movement);
}

In your code,you use AddForce function,so I confirm your player rigidbody doesn't set Kinematic to true.
When your charactor collision with any other objects ,such as ground,wall, your charactor maybe rotate.
You could freeze rigidbody's rotation via inspector like Bijan says.
I don't recommand your use AddForce and MovePosition together.It may has other problem.
like this

This is due to the nature of the Rigidbody component. This component is very lifelike and when force is added and removed, the object still has inertia and therefore the object is still moving.
When it comes to the rotation it is due to the fact that when a force is applied to an object, the object also acquires rotational motion (also known as angular motion).
You can freeze the rotation using the constraints on the Rigidbody component.
Have a deeper look into this component [here].1
In my opinion, it is one of the core components of Unity and it is definitely worth looking into.
I hope I answered your question!

No Bounce after adding velocity In Unity 2d

First of all I'm new to Unity and Game programming. I'm trying to add a cricket bowling like animation. But when the ball touches the ground It doesn't bounce at all and it shows an weird rolling animation.
Here is the GIF,
So I just added the velocity in code,
public class Ball : MonoBehaviour {
public float EndPointX ;
public float EndPointY ;
bool ForceAdded = true;
private Rigidbody2D rigidBody;
void Start () {
rigidBody = GetComponent<Rigidbody2D> ();
}
void Update () {
rigidBody.velocity = new Vector3(EndPointX, EndPointY, 0)*2;
}
}
My Bounce 2d material file,
Ball Properties,
It bounces perfectly without any velocity. I mean when it falls in a straight angle.
Thanx For The Help!!

Since Update() runs every frame, you are continuously setting the velocity, and immediately overwriting the bounce materials attempts to change its direction of movement. If you move the velocity to your Start() method, the velocity will only be set once and the bounciness will be able to influence your object properly.
void Start () {
rigidBody = GetComponent<Rigidbody2D> ();
rigidBody.velocity = new Vector3(EndPointX, EndPointY, 0)*2;
}

UNITY : Ball showing odd behaviour

I have a Ball(sphere) and a floor in my game scene. Ball.cs is attached to the ball to control its movement in the game(Ball only moves in the vertical direction). Both Ball and floor have colliders attached to them and whenever ball touches the floor, the game should ideally end.
OnCollisionEnter2D Method from the Ball.cs script.
private void OnCollisionEnter2D(Collision2D collision)
{
// Zero out the ball's velocity
rb2d.velocity = Vector2.zero;
// If the ball collides with something set it to dead...
isDead = true;
//...and tell the game control about it.
GameController.instance.PlayerDied();
}
Update function
void Update () {
//Don't allow control if the bird has died.
if (isDead == false)
{
//Look for input to trigger a "flap".
if (Input.GetMouseButtonDown(0))
{
//...zero out the birds current y velocity before...
rb2d.velocity = Vector2.zero;
// new Vector2(rb2d.velocity.x, 0);
//..giving the bird some upward force.
rb2d.AddForce(new Vector2(0, upForce));
}
}
}
But what's happening is whenever ball touches the ground, it starts rolling on the ground. It moves few units on +X-axis then rolls back and then ultimately stops.
position.X should ideally be 0(as the ball is moving only in Y-axis and it is during the game) but as soon as ball collides with the floor it starts moving.
I am new to Unity and I have no idea what is wrong.
Why is this happening?
EDIT:
Programmer's answer does work but I still don't understand where the horizontal velocity is coming from(there is horizontal velocity component associated with the ball). I need to know why ball is moving in horizontal direction.

I noticed that you are setting isDead to true when collision happens. If you don't want the ball to move again then set velocity to Vector2.zero; in the Update not only in the OnCollisionEnter2D function. Do this only if isDead is true.
void Update()
{
if (isDead)
{
rb2d.velocity = Vector2.zero;
}
}
Another option is to freeze the constraints when the collision happens. If you want the ball to start rolling again then unfreeze it.
private void OnCollisionEnter2D(Collision2D collision)
{
//Zero out the ball's velocity
rb2d.velocity = Vector2.zero;
//Freeze constraints
rb2d.constraints = RigidbodyConstraints2D.FreezeAll;
// If the ball collides with something set it to dead...
isDead = true;
//...and tell the game control about it.
GameController.instance.PlayerDied();
}
Execute rb2d.constraints = RigidbodyConstraints2D.None; to unfreeze it after.

Air hockey game - Player bat goes through puck if moved too fast

Im currently developing an Air hockey game in Unity3d. The issue I'm having is that when the player attempts to hit the puck too quickly, the player ends up going through the puck and therefore there is no collision. The game works perfectly as expected if the player stays still and the puck hits the player or if the player hits the puck at a slow pace.
The player has a rigidbody using continuous collision detection using a capsule collider. The puck also has rigidbody with continuous dynamic collision detection and a mesh collider with convex.
I tried setting the fixed timestep to 0.01 but that didn't have an effect. Here is the script for the player movement:
void ObjectFollowCursor()
{
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
Vector3 point = ray.origin + (ray.direction * distance);
Vector3 temp = point;
temp.y = 0.2f; // limits player on y axis
cursorObject.position = temp;
}
and here is the code for the puck when it collides with the player:
// If puck hits player
if(collision.gameObject.tag == "Player")
{
Vector3 forceVec = this.GetComponent<Rigidbody>().velocity.normalized * hitForce;
rb.AddForce(forceVec, ForceMode.Impulse);
Debug.Log ("Player Hit");
}
Any help would be much appreciated. Thanks.

The problem you are having its called "tunneling".
This happens because your object is moving at a high speed and in that specific frame the collision is not detected. In frame n the ball is just in front of the bat, but when frame n+1 is calculated the ball has moved behind the bat, thus "missing" the collision completely.
It is a common problem but there are solutions.
I recommend you study this script and try to implement on your game.
This is not my code:
SOURCE: http://wiki.unity3d.com/index.php?title=DontGoThroughThings
using UnityEngine;
using System.Collections;
public class DontGoThroughThings : MonoBehaviour
{
// Careful when setting this to true - it might cause double
// events to be fired - but it won't pass through the trigger
public bool sendTriggerMessage = false;
public LayerMask layerMask = -1; //make sure we aren't in this layer
public float skinWidth = 0.1f; //probably doesn't need to be changed
private float minimumExtent;
private float partialExtent;
private float sqrMinimumExtent;
private Vector3 previousPosition;
private Rigidbody myRigidbody;
private Collider myCollider;
//initialize values
void Start()
{
myRigidbody = GetComponent<Rigidbody>();
myCollider = GetComponent<Collider>();
previousPosition = myRigidbody.position;
minimumExtent = Mathf.Min(Mathf.Min(myCollider.bounds.extents.x, myCollider.bounds.extents.y), myCollider.bounds.extents.z);
partialExtent = minimumExtent * (1.0f - skinWidth);
sqrMinimumExtent = minimumExtent * minimumExtent;
}
void FixedUpdate()
{
//have we moved more than our minimum extent?
Vector3 movementThisStep = myRigidbody.position - previousPosition;
float movementSqrMagnitude = movementThisStep.sqrMagnitude;
if (movementSqrMagnitude > sqrMinimumExtent)
{
float movementMagnitude = Mathf.Sqrt(movementSqrMagnitude);
RaycastHit hitInfo;
//check for obstructions we might have missed
if (Physics.Raycast(previousPosition, movementThisStep, out hitInfo, movementMagnitude, layerMask.value))
{
if (!hitInfo.collider)
return;
if (hitInfo.collider.isTrigger)
hitInfo.collider.SendMessage("OnTriggerEnter", myCollider);
if (!hitInfo.collider.isTrigger)
myRigidbody.position = hitInfo.point - (movementThisStep / movementMagnitude) * partialExtent;
}
}
previousPosition = myRigidbody.position;
}
}

You were right to try continuous collision detection (CCD). There are some constraints (especially in this case where you want to use CCD with two moving objects rather than one moving object and one static object), but it is designed for this kind of scenario. The Rigidbody documentation goes into these constraints:
Set the collision detection mode to Continuous to prevent the
rigidbody from passing through any static (ie, non-rigidbody)
MeshColliders. Set it to Continuous Dynamic to also prevent the
rigidbody from passing through any other supported rigidbodies with
collision detection mode set to Continuous or Continuous Dynamic.
Continuous collision detection is supported for Box-, Sphere- and
CapsuleColliders.
To sum up, both puck and paddle need to be set to Continuous Dynamic, and both need to be Box-, Sphere-, or Capsule Colliders. If you can make these constraints work for your game you should be able to get continuous collision detection without writing it yourself.
A note about Unity's CCD that bears repeating:
Note that continuous collision detection is intended as a safety net
to catch collisions in cases where objects would otherwise pass
through each other, but will not deliver physically accurate collision
results, so you might still consider decreasing the fixed Time step
value in the TimeManager inspector to make the simulation more
precise, if you run into problems with fast moving objects.
But since you are manually specifying the collision reaction, that might not be an issue.