something wrong with rotation controls in 2d top down shooter in unity3d

Question

I am trying to get my character to face the mouse by rotating on its y axis. It rotates a little, but it do not face the mouse. The Camera's position is directly above the player, and its in orthographic view I see many other examples of top down shooters and there almost exactly like mine so i don't know whats the problem please help thank you.

using UnityEngine;
using System.Collections;

public class playermovementscript : MonoBehaviour { 

public float movementspeed = 5f; 
public float bulletspeed  = 10f;
public GameObject bullet; 
public GameObject shooter;  
public Vector3 target;  
public Camera camera;

// Use this for initialization
void Start () {  
    //refrence to main camera
    Camera camera;

}

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

    //call movement function in every frame
    movement (); 

    // cheek for input of f in every frame if true execute shoot function
    if (Input.GetKeyDown (KeyCode.F)) {
        shoot();
    } 

 } 




void movement(){

    // makes refrence to gameobjects rigidbody and makes its velocity varible to equal values of axis x and y
    gameObject.GetComponent<Rigidbody>().velocity = new Vector3(Input.GetAxisRaw("Horizontal")*movementspeed,0,Input.GetAxisRaw("Vertical")*movementspeed); 

// makes vector 3 type target equall to mouse position on pixial cordinates converted in to real world coordniates
    target = camera.ViewportToWorldPoint (new Vector3(Input.mousePosition.x,Input.mousePosition.y,camera.transform.position.y - transform.position.y)); 

    //target.x -= transform.position.x; 
    //target.z -= transform.position.z;
    // states the vector 3 values of target 
    Debug.Log (target);  
    // makes object local z face target and iniziates up axis
    transform.LookAt (target,Vector3.up);

}  

Answer 1

Going to make an attempt to explain what's going on...

target = camera.ViewportToWorldPoint (new Vector3(Input.mousePosition.x,Input.mousePosition.y,camera.transform.position.y - transform.position.y)); 

The above code is trying to convert a mouse position which is in Screen Space (which measures the position from (0,0) to the width/height of the screen in pixels) to a Viewport Space (which measure the same screen but with a different measure, it measures the positions from (0,0) to (1,1)).

In Unity

• Screen Space Measurement: Origin (0,0) to the max width/height
• Viewport Measurement: Origin (0,0) to (1,1)
• Reference: http://docs.unity3d.com/ScriptReference/Camera.html

If you desire to still use "ViewportToWorldPoint" then you could do a "ScreenToViewportPoint" then follow it with a "ViewPortToWorldPoint".

Otherwise, you could look into using "ScreenToWorldPoint" from the start.