Should the cursor be locked?

The cursor will automatically be hidden, centered on view and made to never leave the view.

In the web player, the cursor may only be locked after the user has clicked on the content and the user has not left the content view with the cursor. After the user presses escape or switches to another application the cursor will be automatically unlocked. The cursor lock will also be lost when exiting full screen mode. You can query if the cursor is currently locked by checking the lockCursor state. To provide a good user experience it is recommended to only lock the cursor as a result of pressing a button. Also you should check if the cursor got unlocked, in order to e.g. pause the game or bring up a game menu. In the Web Player and Editor the cursor will automatically be unlocked when you press escape. In the Standalone Player you have full control over mouse locking thus it won't automatically lose mouse lock unless you switch applications.

	// Called when the cursor is actually being locked
	function DidLockCursor () {
		Debug.Log("Locking cursor");
		// Disable the button
		guiTexture.enabled = false;
	}
	// Called when the cursor is being unlocked
	// or by a script calling Screen.lockCursor = false;
	function DidUnlockCursor () {
		Debug.Log("Unlocking cursor");
		// Show the button again
		guiTexture.enabled = true;
	}
	function OnMouseDown () {
		// Lock the cursor
		Screen.lockCursor = true;
	}
	private var wasLocked = false;
	function Update () {
		// In standalone player we have to provide our own key
		// input for unlocking the cursor
		if (Input.GetKeyDown ("escape"))
			Screen.lockCursor = false;
		// Did we lose cursor locking?
		// eg. because the user pressed escape
		// or because he switched to another application
		// or because some script set Screen.lockCursor = false;
		if (!Screen.lockCursor && wasLocked) {
			wasLocked = false;
			DidUnlockCursor();
		}
		// Did we gain cursor locking?
		else if (Screen.lockCursor && !wasLocked) {
			wasLocked = true;
			DidLockCursor ();
		}
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void DidLockCursor() {
        Debug.Log("Locking cursor");
        guiTexture.enabled = false;
    }
    void DidUnlockCursor() {
        Debug.Log("Unlocking cursor");
        guiTexture.enabled = true;
    }
    void OnMouseDown() {
        Screen.lockCursor = true;
    }
    private bool wasLocked = false;
    void Update() {
        if (Input.GetKeyDown("escape"))
            Screen.lockCursor = false;
        
        if (!Screen.lockCursor && wasLocked) {
            wasLocked = false;
            DidUnlockCursor();
        } else
            if (Screen.lockCursor && !wasLocked) {
                wasLocked = true;
                DidLockCursor();
            }
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def DidLockCursor() as void:
		Debug.Log('Locking cursor')
		guiTexture.enabled = false

	def DidUnlockCursor() as void:
		Debug.Log('Unlocking cursor')
		guiTexture.enabled = true

	def OnMouseDown() as void:
		Screen.lockCursor = true

	private wasLocked as bool = false

	def Update() as void:
		if Input.GetKeyDown('escape'):
			Screen.lockCursor = false
		if (not Screen.lockCursor) and wasLocked:
			wasLocked = false
			DidUnlockCursor()
		elif Screen.lockCursor and (not wasLocked):
			wasLocked = true
			DidLockCursor()