Move forward a sprite 2d in clicking on it in Unity 3d

Question

Unity version:2021.1.24f1

Hello, currently I am creating a 2D game with Unity 3d; I wish that when I click with my mouse and the cursor is above my sprite it goes up 15 pixels; it moves vertically and horizontally

My script:

    using UnityEngine;
    
    public class PlayerMovement : MonoBehaviour
    {
        Rigidbody m_Rigidbody;
        float m_speed;
        
    
        void Start(){
            m_Rigidbody = GetComponent<Rigidbody>();
            m_speed = 5f;
        }
    
        void Update()
        //bouton gauche de la souris
        {if (Input.GetMouseButtonDown(0)){
            m_Rigidbody.velocity = transform.forward(new Vector2(0,-1) * Time.deltaTime * m_speed, Space.World);
            
        }
        //bouton droit de la souris
        if(Input.GetMouseButtonDown(1)){
            m_Rigidbody.velocity = transform.forward(new Vector2(-1, 0) * Time.deltaTime*m_speed, Space.World);
        }
        //roulette de la souris
        if(Input.GetMouseButtonDown(2)){
            m_Rigidbody.velocity = transform.forward (new Vector2(0,-1) * Time.deltaTime * m_speed, Space.World);
        }
    
            
        }
    }```

Answer 1

One of the mistakes that you're making is that you're using a Rigidbody component in a 2D game. You should be using a Rigidbody2D component.

The other one, making the error that you stated below is that you're using transform.forward as a method, when in fact it's just a Vector3(0,0,1). So, if you want to go up (not forward, it's 2D), just use transform.up alone, or new Vector2(0,1) without multiplying one by the other, which doesn't really make sense.

You also shouldn't modify the rb.velocity value directly and I don't know if it is even possible. There's a built-in Unity function, Rigidbody2D.AddForce(Vector2) So try using:

m_Rigidbody.AddForce(transform.up * Time.deltaTime * m_speed);

That should work. I also don't know why you are changing the velocity/force added with time, because that will make the player go faster, and faster, but it's your code.