How can I rotate 2d object in direction of mouse pointer

Questions & Answers
1

I am working in 2d. I need to accomplish a very simple thing. I have a prefab and I need to rotate it during the runtime in a direction where mouse pointer is. Basically I need this (black point is a mouse pointer):
32202-q1.png

When I move it up I want to accomplish this:

32203-q2.png
32203-q2.png764×372 14.1 KB

I created a simple script for that:

Vector3 position = Input.mousePosition;
position.z = this.transform.position.z;
this.objrigid.transform.rotation = Quaternion.FromToRotation(position, this.objrigid.position);

I was assuming that FromToRotation will rotate object in direction from 1 point to another point, but it doesn’t really do that, object is randomly rotated when I move mouse, but in totally wrong directions. How would I accomplish this?

2

I use this script to make my player sprite look towards the mouse

    Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
    transform.rotation = Quaternion.LookRotation(Vector3.forward, mousePos - transform.position);

Hope it’ll work for you. :smiley:

3

Hey Petrbena

Your mistake is a very common one! Input.mousePosition returns a Vector3 in screen co-ordinates, whereas Transform.position returns a Vector3 in world co-ordinates.

In order to convert the co-ordinates you will need to use a Camera:
http://docs.unity3d.com/ScriptReference/Camera.WorldToScreenPoint.html

4

I’ve made this script that gets a normalized Direction towards the mouse.
It does this based on your ViewPort, Just give it a shot and play around with it.

using UnityEngine;
using System.Collections;

public class NormMouse : MonoBehaviour {

    public static NormMouse Instance;
    void Awake() { Instance = this; }

    Vector3 viewPortActual, viewPortDelta, directionToMouse;

    /// <summary>
    /// Retrieves a Normalized Vector3 Direction from mPosition towards the MousePos
    /// </summary>
    /// <returns>a Normalized Vector3 Direction from mPosition towards the MousePos (as WorldPos)</returns>
    public Vector3 GetNormalizedDirectionToMouse()
    {
        // Calculate a direction based on the Mouse Position (using Viewport)
        viewPortActual = Camera.main.ScreenToViewportPoint(Input.mousePosition);
        viewPortDelta = new Vector3(0.5f, 0.5f, 0); // Detract Half the screen
        directionToMouse = viewPortActual - viewPortDelta; // Caculate Direction
        return directionToMouse.normalized; // Return normalized Direction
    }
}

Here, I made another Class for you that looks at the position using my above code from afar :slight_smile:
Make sure the NormMouse script is somewhere in the scene, and there can be only one of them, because Singleton is applied :slight_smile:

using UnityEngine;
using System.Collections;

public class LookAtMouse : MonoBehaviour {

Transform mTransform;

void Start()
{
    mTransform = transform;
}

// Update is called once per frame
void Update () {
    mTransform.LookAt(mTransform.position + NormMouse.Instance.GetNormalizedDirectionToMouse());
}

I think that’s about the best explanation I can give you, but if you have any more questions, or need any details, fire away! If not, please accept this answer :wink:
Best of luck ;3