Unity in Practice 0011 – Player Jump with Ground Check in Unity

To implement a player jump with a condition and ground check in Unity (using C#), you’ll typically use Rigidbody physics and a ground detection method like Physics.Raycast, Collider overlap checks, or Unity’s CharacterController.isGrounded.

Here’s a basic example using Rigidbody and a ground check via Physics.Raycast.

🎮 Step-by-Step: Setup Ground Layer in Unity

✅ 1. Add a Layer and Name it “Ground”

In Unity, go to the top right of the Inspector panel and click the Layer dropdown.
Click “Add Layer…”.
In an empty slot (e.g., User Layer 8+), enter Ground as the name.
Press Enter to confirm.

✅ 2. Assign Layer to Objects

Select both your VGround and HGround GameObjects in the Hierarchy.
In the top right corner of the Inspector, click the Layer dropdown.
Choose Ground.
When prompted, click “Yes, change children” (if they have children).

✅ 3. Assign Layer to Objects

Add these fields for configuring in the Unity Inspector:

[SerializeField] private LayerMask groundLayer;
[SerializeField] private float groundCheckDistance;

💻 Update Your C# Script

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

public class BallScript : MonoBehaviour
{

    private Rigidbody2D rb;
    private Animator playerAnim;

    [SerializeField] private float moveSpeed = 5;
    [SerializeField] private float jumpForce = 10;

    private float xInput;

    private int facingDirection = 1;
    private bool facingRight = true;

    [Header("Collision Info")]
    [SerializeField] private LayerMask groundLayer;
    [SerializeField] private float groundCheckDistance;
    private bool isGrounded;

    // Start is called before the first frame update
    void Start()
    {
        rb = GetComponent<Rigidbody2D>();
        playerAnim = GetComponentInChildren<Animator>();
    }

    // Update is called once per frame
    void Update()
    {
        CheckInput();

        CollisionChecks();

        Movement();

        // Flip the player based on input direction
        FlipController();

        AnimatePlayer();
    }


    private void CollisionChecks()
    {
        isGrounded = Physics2D.Raycast(transform.position, Vector2.down, groundCheckDistance, groundLayer);
    }

    private void CheckInput()
    {
        // Get horizontal input
        xInput = Input.GetAxis("Horizontal");

        // Jump on Space key press
        if (Input.GetKeyDown(KeyCode.Space))
        {
            Jump();
        }
    }

    private void Movement()
    {
        // Apply horizontal movement
        rb.velocity = new Vector2(xInput * moveSpeed, rb.velocity.y);
    }

    private void Jump()
    {
        if (isGrounded)
        {
            rb.velocity = new Vector2(rb.velocity.x, jumpForce);
        }
    }

    private void AnimatePlayer()
    {
        // Animate player running
        bool isRun = rb.velocity.x != 0;
        playerAnim.SetBool("IsRun", isRun);
    }

    private void Flip()
    {
        facingDirection = facingDirection * -1;
        facingRight = !facingRight;

        transform.Rotate(0, 180, 0);
    }

    private void FlipController()
    {
        if (rb.velocity.x > 0 && !facingRight)
        {
            Flip();
        }
        else if (rb.velocity.x < 0 && facingRight)
        {
            Flip();
        }
    }

    private void OnDrawGizmos()
    {
        Gizmos.DrawLine(transform.position, new Vector3(transform.position.x, transform.position.y - groundCheckDistance));

    }
}