zz.util.keyboard

gistfile1.js

// create zz namespace
var zz = zz = zz || {};
// create zz.util namespace
zz.util = zz.util = zz.util || {};
// create zz.util.keyboard prototype
zz.util.keyboard = cc.Class.extend( /** @lends zz.util.keyboard# */ {
    _keys: {},
    /**
     * Constructor
     */
    ctor: function() {
        this._initKeyboard();
        _keys = {};
    },
    _initKeyboard: function() {
        log('keyboard initialize');
    },
    // set the key to be down
    // key is a number or constant
    keyDown: function(key) {
        if (this._keys[key] == undefined) {
            this._keys[key] = [];
        }
        this._keys[key]['strokeFromHold'] = this._keys[key]['isDown'];
        this._keys[key]['isDown'] = true;
        this._keys[key]['eventJustHappened'] = true;
    },
    // set the key to be up
    // key is a number or constant
    keyUp: function(key) {
        this._keys[key]['isDown'] = false;
        this._keys[key]['strokeFromHold'] = false;
        this._keys[key]['eventJustHappened'] = true;
    },
    // get if the key is down
    // key is a number or constant
    keyIsDown: function(key) {
        if (this._keys[key] != undefined) {
            return this._keys[key]['isDown'];
        }
    },
    // get if the key was pressed just before this tick
    // key is a number or constant
    keyJustPressed: function(key, ignoreHeldStrokes) {
        if (this._keys[key] != undefined) {
            if (ignoreHeldStrokes) {
                return this._keys[key]['isDown'] && this._keys[key]['eventJustHappened'] && !(this._keys[key]['strokeFromHold']);
            } else {
                return this._keys[key]['isDown'] && this._keys[key]['eventJustHappened'];
            }
        }
    },
    // get if the key was released just before this tick
    // key is a number or constant
    keyJustReleased: function(key) {
        if (this._keys[key] != undefined) {
            return !this._keys[key]['isDown'] && this._keys[key]['eventJustHappened'];
        }
    },
    // update the keyboard object at the end of the tick (because 'just pressed' events will be set to 'not just pressed')
    update: function(dt) {
        for (k in this._keys) {
            //log(k +' = '+ this._keys[k][0] + " " + this._keys[k][1]);
            this._keys[k]['eventJustHappened'] = false;
            if (!this._keys[k]['isDown']) {
                this._keys[k] = null;
                delete this._keys[k];
            }
        }
    },
    // debug: get list of currently tracked keys
    getListOfPressedKeys: function() {
        var keyList = '';
        for (x in this._keys) {
            for (y in cc.KEY) {
                var keyCode = cc.KEY[y];
                if (x == keyCode) {
                    keyList += y + ' ';
                    break;
                }
            }
        }
        return keyList;
    },
    // description of object
    description: function() {
        return 'zz.util.keyboard' + JSON.stringify(this) + ';';
    }
});
debug('loaded', 'zz.util.keyboard');
/*

This is a class I wrote for a game which uses Cocos2d-html5.
You can see that the class uses the cocos2d function cc.Class.extend().
The code allows the creation of a keyboard object which can store the states of keypresses.
The keyboard object can determine if a key is down, up, just pressed, just released, or
if the key is being held down and re-firing.
I like how useful it is and the functionality it provides to a game developer.

I dislike how it is dependent upon using the cocos2d base class prototype.
*/