My 2D Character is not jumping at all

Question

I am having an issue with my character which is not jumping at all. I am new to Unity, but I made sure to apply the script to the player and adjust the speed, I did not touch the Rigidbody 2D. If any one can help me figure our the issue, it will be much appreciated.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerController : MonoBehaviour {

public float moveSpeed;
public float jumpSpeed;
public bool grounded = false;
private Rigidbody2D rb;

void Start() {
    rb = GetComponent<Rigidbody2D>();
}

void Update () {

    transform.Translate (Input.GetAxisRaw ("Horizontal") * moveSpeed * Time.deltaTime, 0, 0);

    if (grounded) 
    {
        if (Input.GetButtonDown ("Jump"))
        {
            rb.AddForce (Vector2.up * jumpSpeed);
            grounded = false;
        }
    }
}


void OnCollisionEnter2D (Collision2D coll){
    if (coll.transform.tag == "Ground") 
    {
        grounded = true;
    }
}

}

Inspector window of the Player GameObject

Inspector window of the Ground GameObject

Answer 1

Your problem is you haven't tag the Ground GameObject as so. So in the OnCollisionEnter2D the character detects the collision, but the if (coll.transform.tag == "Ground") will never be true. So it means the character can't be grounded

Since to be grounded is the first condition to check if the player pressed the Jump key. It is impossible it will ever jump

if (grounded) 
    {
        if (Input.GetButtonDown ("Jump"))
        {
            rb.AddForce (Vector2.up * jumpSpeed);
            grounded = false;
        }
    }

To solve this issue: You need to tag the Ground GameObject as so. In case you are not sure how to do that, on the Tag menu, create (if it doesnt exist already) a new tag called Ground. Then assign in that same menu the Ground Tag to the Ground GameObject. Here you can learn how in case you need a visual reference:

https://docs.unity3d.com/Manual/Tags.html

Edit: You can try this script if everything fails. It should work. I used my self some time ago, I cleaned the code so to leave only what you need to move the character in the x and y axis. Hope to have included everything you need:

public class CharacterController2D : MonoBehaviour {

    // LayerMask to determine what is considered ground for the player
    public LayerMask whatIsGround;

    // Transform just below feet for checking if player is grounded
    public Transform groundCheck;

    // store references to components on the gameObject
    Transform transform;
    Rigidbody2D rigidbody;

    bool isGrounded = false;

    float vy;
    float vx;

    public float jumpForce = 600f;

    void Awake () {
        transform = GetComponent<Transform> ();
        rigidbody = GetComponent<Rigidbody2D> ();
    }


    void Update()
    {

        // determine horizontal velocity change based on the horizontal input
        vx = Input.GetAxisRaw ("Horizontal");
        vy = rigidbody.velocity.y;

        // Check to see if character is grounded by raycasting from the middle of the player
        // down to the groundCheck position and see if collected with gameobjects on the
        // whatIsGround layer
        isGrounded = Physics2D.Linecast(transform.position, groundCheck.position, whatIsGround);

        if(isGrounded && Input.GetButtonDown("Jump")) // If grounded AND jump button pressed, then allow the player to jump
        {
            DoJump();
        }

        // Change the actual velocity on the rigidbody
        rigidbody.velocity = new Vector2(_vx * MoveSpeed, _vy);

    }

    //Make the player jump
    void DoJump()
    {
        // reset current vertical motion to 0 prior to jump
        vy = 0f;
        // add a force in the up direction
        rigidbody.AddForce (new Vector2 (0, jumpForce));

    }
}

So things to take into account:

• Instead of tag the ground, you create a layer with everything you consider ground. That will include possible platforms the character may jump over. Pass as a parameter this layer to the script in the inspector

• You need to place an empty GameObject in the feet of the character. You will drag and drop that GameObject in the editor onto the groundCheck public variable.

• Instead of OnTriggerEnter, you will use Physics2D.Linecast which will trave a line from the position of the character to under its feet (where you should have place the Transform mentioned in the previous step) and if in the middle there is an element of the groundLayer, it means the character will be grounded.

Let me know if anything is not clear or if you find some bug.

Answer 2

As mentioned your problem is deffinetly that your missing to tag your ground object :)

A tip: What i like to do when i have problems like this is to use the unitys Debug.Log() to locate where the problem is it. It will let you know easily in the console what code is run and which is not. Try do the following:

void Update () {

transform.Translate (Input.GetAxisRaw ("Horizontal") * moveSpeed * Time.deltaTime, 0, 0);

if (grounded) 
{
    Debug.Log("Is grounded");

    if (Input.GetButtonDown ("Jump"))
    {
        Debug.Log("Jump clicked");
        rb.AddForce (Vector2.up * jumpSpeed);
        grounded = false;
    }
}

}