Running script isn't working correctly

Questions & Answers
1

Newbie here, I’m working on a running script for a 2D platformer but I can’t get it to work. Here’s what I’ve got so far:

using UnityEngine;
using System.Collections;

public class nuntiControllerScript : MonoBehaviour {
    public float maxSpeed = 10f;
    bool facingRight = true;
    public float move;
    Animator anim;

    // Use this for initialization
    void Start()
    {

        //The animator is called in order to play a running animation.

        anim = GetComponent<Animator>();
    }

    // Update is called once per frame
    void FixedUpdate()
    {

        //While the D key is held down, move is 1

        while (Input.GetKey(KeyCode.D))
        {
            move = 1;
        };

        //while the A key is held down, move is -1

        while (Input.GetKey(KeyCode.A))
        {
            move = -1;
        };

        //The value of the speed parameter is altered to be equal to the value of move. This causes the idle animation to transition into running.

        anim.SetFloat("Speed", Mathf.Abs(move));

        //The velocity of the character is 10 x move, which is either 1, so the character moves to the right, or -1 so he moves to the left

        GetComponent<Rigidbody2D>().velocity = new Vector2(move * maxSpeed, GetComponent<Rigidbody2D>().velocity.y);

        if (move > 0 && !facingRight)      //If the move is greater than 0 and you aren't facing right,
            Flip();                        //turn around so you are.
        else if (move < 0 && facingRight)  //If the move is less than 0 and you are facing right,
        {                                  //turn around to face left and set facingRight to false.
            Flip();
            facingRight = false;
        }
            
    }

    void Flip()
    {
        facingRight = !facingRight;
        Vector3 theScale = transform.localScale;
        theScale.x *= -1;
        transform.localScale = theScale;
    }
}

Whenever I try and run the code as it is now, the program crashes. I’ve also had issues where:

  • the sprite would move, albeit only to the left, but there’d be huge lag and the sprite wouldn’t flip
  • the sprite would just rotate slightly to the right when the right arrrow key was pressed
  • the sprite just wouldn’t move (This was the most common problem)

I’ve been trying to make this work for a couple of days now. Anyone got any advice?

2

Don’t ever use while() in Update() - you’ll hold up your entire execution thread by going round and round in that loop until it’s no longer true (in your case, for as long as you’re holding down the A or D keys).

I suspect you meant:

     if(Input.GetKey(KeyCode.D))
     {
         move = 1;
     };

     //while the A key is held down, move is -1

     if(Input.GetKey(KeyCode.A))
     {
         move = -1;
     };

However, note that even then you shouldn’t really check for input inside FixedUpdate - fixed update is intended for physics updates or other events that need to happen on a regular, fixed timestep - listening for input etc. that needs to be done in every frame should be in Update().
You might want to look through some of the tutorials at Learn game development w/ Unity | Courses & tutorials in game design, VR, AR, & Real-time 3D | Unity Learn