Help detecting when object is grounded

Questions & Answers
1

I am unsure how to make it so I can jump only when my character is on the ground I assume it has to do with OnCollisionEnter and OnCollisionExit but am unsure what to put in.

Here is my Script

using UnityEngine;
using System.Collections;

public class Runner : MonoBehaviour 
{
	public float Speed =1;
	public Vector3 JumpHeight = new Vector3();
	public bool IsOnGround = true;
	public float DeathHeight =-10;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () 
	{
		if (!IsOnGround)
		{
			rigidbody.AddForce (new Vector3 (Speed, 0, 0), ForceMode.Acceleration);
		}
		if (gameObject.transform.position.y < DeathHeight) 
		{
			rigidbody.velocity = new Vector3();
			gameObject.transform.position = new Vector3(1,1,0);
		}
		if (Input.GetMouseButtonDown (0)) 
		{
			IsOnGround = false;
			rigidbody.AddForce(JumpHeight,ForceMode.Impulse);
		}

	}

	void OnCollisionEnter()
	{
		IsOnGround = true;
	}


	void OnCollisionStay()
	{
		IsOnGround = true;
	}


	void OnCollisionExit()
	{
		IsOnGround = false;
	}

I am unsure what to put in the script to make it so the jump only works when I am on an object. (This is for an endless runner if that helps at all)

2

You have many different ways to check if character is grounded and i’ll describe 2 of them. These should help you to figure out you own check method.

  1. You can check rigidbody.velocity.y to check if he’s not moving verticaly and use colliders to check for ground:

    if(rigidbody.velocity.y != 0.0f && !touchingGround) isGrounded = false;

    void OnCollisionEnter(Collision col){
    if(col.tag == “ground”) touchingGround = true;
    }

  2. You can use empty game object and place it under your characters feet. Add collider to this empty object and set to be a trigger then :

    void OnCollisionEnter(Collision col){
    PlayerMovement.isGrounded = true;
    }
    void OnCollisionExit(Collision col){
    PlayerMovement.isGrounded = false;
    }