File: js\grape\game\game.js
define(['../class', '../env', '../etc/event-emitter', './game-loop', './input', './scene'], function (Class, Env, EventEmitter, GameLoop, Input, Scene) {
/**
* A class that represents a game. You can create and run multiple games in a single page.
*
* @class Grape.Game
* @uses Grape.EventEmitter
* @constructor
* @param {Object} opts Initial properties
*/
return Class('Game', EventEmitter, {
init: function (opts) {
opts = opts || {};
/**
* The scene which starts when (re)starting the game.
* It should be a constructor or a function returning with the scene, not an instantiated scene.
*
* @property initialScene
* @type {Function}
* @default Grape.Scene
*/
this.initialScene = opts.initialScene || Scene;
/* istanbul ignore else */
if (opts.hasOwnProperty('container')) { //null and undefined too
/**
* The dom element which serves as the screen of the game. The size of the container is not manipulated
* by the engine, therefore you should set the size of it. The engine handles when this "screen size"
* changes and updates the displayed views. The container can be an id of a html element or a html
* element itself.
*
* @property container
* @type {String|HTMLElement}
* @default document.body
*/
this.container = opts.container;
} else if (Env.browser) {
this.container = document.body;
}
this.gameLoop = this.createGameLoop();
/* istanbul ignore else */
if (Env.browser) {
this.input = new Input({reservedKeys: opts.reservedKeys});
}
},
/**
* This method is called once when the game is created. If you want to use a custom game loop for your game, you
* can override this method.
*
* @method createGameLoop
* @return {Grape.GameLoop} The game loop
*/
createGameLoop: function () {
return new GameLoop(this);
},
/**
* Starts the game. Initializes the game screen, the input system, and the game loop.
*
* @method start
* @param {Grape.Scene} [scene] Initial scene, which overrides the initialScene property.
*/
'final start': function (scene) {
if (this.gameLoop.isRunning()) {
throw new Error('already running');
}
//initialize screen
/* istanbul ignore else */
if (Env.browser) {
if (typeof this.container === 'string') {
this.container = document.getElementById(this.container);
}
if (!this.container) {
throw new Error('Container does not exists!');
}
this.container.innerHTML = ''; //todov2 test restart
this._screen = document.createElement('div');
this._screen.style.position = 'relative';
this._screen.style.float = 'left';
this._screen.style.width = '100%';
this._screen.style.height = '100%';
this._screen.style.overflow = 'hidden';
this.container.appendChild(this._screen);
}
this._starting = true; //startScene can run now
/* istanbul ignore else */
if (this.input) {
this.input._start(this._screen);
}
scene = scene || this.initialScene;
this.startScene(typeof scene === 'function' ? new scene() : scene);
this._starting = false;
this.gameLoop.start();
},
/**
* Stops the game.
*
* @method stop
*/
'final stop': function () { //TODOv2 remove screen
this.gameLoop.stop();
/* istanbul ignore else */
if (this.input) {
this.input._stop();
}
/**
* Fired when the stop() method is called.
*
* @event stop
*/
this.emit('stop');
},
/**
* Starts a new scene in the game.
*
* @method startScene
* @param {Scene} scene The scene
*/
startScene: function (scene) {
if (!this._starting && !this.gameLoop.isRunning()) {
throw new Error('Game is not running! You can game.start(scene).');
}
if (scene._game) {
throw new Error('Scene already started!');
}
if (this.scene) {
/**
* Fired to the scene when the scene is stopped.
*
* @event stop (scene)
*/
this.scene.emit('stop');
this.scene._game = null;
}
scene._game = this;
this.scene = scene;
/**
* Emitted to the scene when started. The parameter is the game.
*
* @event start (scene)
*/
scene.emit('start', this);
},
/**
* Called by the game loop in each frame.
*
* @method frame
*/
frame: function () {
/**
* Fired in each frame
*
* @event frame
*/
this.emit('frame');
/**
* Fired to the actual scene in each frame
*
* @event frame (scene)
*/
this.scene.emit('frame');
/* istanbul ignore else */
if (this.input) {
this.input._emitEvents(this.scene); //TODOv2 is it wrong? ie. keyPress.none?
}
},
/**
* Called by the game loop when at least one frame was executed since the last screen update.
*
* @method render
*/
render: function () {
/* istanbul ignore else */
if (Env.browser) {
/**
* Fired to the current scene in each render frame
*
* @event renderLayer (scene)
*/
this.scene.emit('renderLayer');
}
},
/**
* Returns the game screen which is appended to the container.
*
* @method getScreen
* @return {HTMLElement} Screen element
*/
getScreen: function () {
return this._screen;
},
/**
* Returns the width of the screen.
*
* @method getScreenWidth
* @return {Number} Width
*/
getScreenWidth: function () {
/* istanbul ignore next */
return this._screen ? this._screen.offsetWidth : 1;
},
/**
* Returns the height of the screen.
*
* @method getScreenHeight
* @return {Number} Height
*/
getScreenHeight: function () {
/* istanbul ignore next */
return this._screen ? this._screen.offsetHeight : 1;
},
/**
* Sets the cursor style for the screen.
*
* @method setCursor
* @param {String} cursor new cursor style
*/
setCursor: /* istanbul ignore next */ function (cursor) {
if (!this._screen) {
return;
}
this._screen.style.cursor = cursor;
},
/**
* Returns the current scene.
*
* @method getScene
* @return {Grape.Scene}
*/
getScene: function () {
return this.scene; //todov2 rename to _scene
},
/**
* This method is called by the game loop to determine what is the required FPS (Frames Per Second) for the
* game. By default, this is decided by the "fps" property of the current scene.
*
* @method getRequiredFps
* @return {Number} FPS
*/
getRequiredFps: function () {
return this.scene.fps;
}
});
});
