How to stop movement, when mouse is off screen

Question

I'm hoping there's someone out there that can help me with a small problem.

Currently I have an Input Manager attached to the main camera to allow the user to pan around the map by moving the mouse to the edges of the window, but I've encountered a slight problem which I've tried to fix myself to no avail.

If the mouse goes outside of the window, the panning still happens, which I find irritating when I'm debugging or using other applications. So I am hoping that someone can help me to stop the movement happening when the mouse is outside the game window.

Here is the code for my Input Manager.

using UnityEngine;
using System.Collections;

public class InputManager : MonoBehaviour {

    public Vector3 position = new Vector3(0,0, -10);
    public int boundary = 50;
    public int speed = 4;

    private int screenBoundsWidth;
    private int screenBoundsHeight;

    // Use this for initialization
    void Start()
    {
        screenBoundsWidth = Screen.width;
        screenBoundsHeight = Screen.height;

    }

    // Update is called once per frame
    void Update()
    {
        if (Input.mousePosition.x > screenBoundsWidth - boundary) {
            position.x += speed * Time.deltaTime;
        }

        if (Input.mousePosition.x < 0 + boundary) {
            position.x -= speed * Time.deltaTime;
        }

        if (Input.mousePosition.y > screenBoundsHeight - 10) {
            position.y += speed * Time.deltaTime;
        }

        if (Input.mousePosition.y < 0 + boundary) {
            position.y -= speed * Time.deltaTime;
        }   

        Camera.mainCamera.transform.position = position;
    }
}

Thank you for your time.

EDIT

I have come up with a hacky work around, but it still causes the movement to happen in certain locations around the outside of the window. I am hoping someone can come up with a better solution.

if (Input.mousePosition.x  < screenBoundsWidth && Input.mousePosition.y < screenBoundsHeight) {
    if (Input.mousePosition.x > screenBoundsWidth - boundary) {
        position.x += speed * Time.deltaTime;
    }
}

if (Input.mousePosition.x > 0 && Input.mousePosition.y > 0) {
    if (Input.mousePosition.x < 0 + boundary) {
        position.x -= speed * Time.deltaTime;
    }
}

if (Input.mousePosition.y < screenBoundsHeight && Input.mousePosition.x < screenBoundsWidth) {
    if (Input.mousePosition.y > screenBoundsHeight - 22) {
        position.y += speed * Time.deltaTime;
    }
}

if (Input.mousePosition.y > 0 && Input.mousePosition.x > 0) {
    if (Input.mousePosition.y < 0 + boundary) {
        position.y -= speed * Time.deltaTime;
    }
}

Answer 1

Due to the way Unity and the various host operating systems interact, you have limited control of the mouse cursor. (in short the OS controls the mouse Unity just reads it) That being said you do have some options. Screen.lockCursor jumps to mind.

http://docs.unity3d.com/Documentation/ScriptReference/Screen-lockCursor.html

It won't do exactly what you are looking for but it might be a good starting point

Answer 2

3 Ideas:

Rect screenRect = new Rect(0,0, Screen.width, Screen.height);
if (!screenRect.Contains(Input.mousePosition))
    return;

The same can be written more verbously as:

float mouseX = Input.MousePosition.x;
float mouseY = Input.MousePosition.y;
float screenX = Screen.width;
float screenY = Screen.height;

if (mouseX < 0 || mouseX > screenX || mouseY < 0 || mouseY > screenY)
    return;

// your Update body

...which is pretty much the same as your "hacky" solution (which is completely valid imho).

Another option is to create 4 Rect objects for each screen border, then check if mouse is inside those rects. Example:

public float boundary = 50;
public float speed = 4;
private Rect bottomBorder;
private Rect topBorder;
private Transform cameraTransform;

private void Start()
{
    cameraTransform = Camera.mainCamera.transform
    bottomBorder = new Rect(0, 0, Screen.width, boundary);
    topBorder = new Rect(0, Screen.height - boundary, Screen.width, boundary);
}

private void Update()
{
    if (topBorder.Contains(Input.mousePosition))
    {
        position.y += speed * Time.deltaTime;
    }

    if (bottomBorder.Contains(Input.mousePosition))
    {
        position.y -= speed * Time.deltaTime;
    }

    cameraTransform.position = position;
}

The tricky part here is that Rect coordinates have Y axis pointing down and Input.mousePosition has Y pointing up... so bottomBorder Rect has to be on the top, and topBorder has to be at the bottom. Left and right borders are not affected.

Answer 3

Time.speed = 0;

is this what you want?