本文基于 Cocos Creator 2.4.1 撰写。
文件目录：
/**
* !#zh
* 这里是一些用来判断执行环境的宏，这些宏都是全局变量，直接访问即可。<br>
* 在项目构建时，这些宏将会被预处理并根据构建的平台剔除不需要的代码，例如
*
* if (CC_DEBUG) {
* cc.log('debug');
* }
* else {
* cc.log('release');
* }
*
* 在构建后会只剩下
*
* cc.log('release');
*
* <br>
* 如需判断脚本是否运行于指定平台，可以用如下表达式：
*
* {
* "编辑器": CC_EDITOR,
* "编辑器 或 预览": CC_DEV,
* "编辑器 或 预览 或 构建调试": CC_DEBUG,
* "网页预览": CC_PREVIEW && !CC_JSB,
* "模拟器预览": CC_PREVIEW && CC_JSB,
* "构建调试": CC_BUILD && CC_DEBUG,
* "构建发行": CC_BUILD && !CC_DEBUG,
* }
*
* !#en
* Here are some of the macro used to determine the execution environment, these macros are global variables, can be accessed directly.<br>
* When the project is built, these macros will be preprocessed and discard unreachable code based on the built platform, for example:
*
* if (CC_DEBUG) {
* cc.log('debug');
* }
* else {
* cc.log('release');
* }
*
* After build will become:
*
* cc.log('release');
*
* <br>
* To determine whether the script is running on the specified platform, you can use the following expression:
*
* {
* "editor": CC_EDITOR,
* "editor or preview": CC_DEV,
* "editor or preview or build in debug mode": CC_DEBUG,
* "web preview": CC_PREVIEW && !CC_JSB,
* "simulator preview": CC_PREVIEW && CC_JSB,
* "build in debug mode": CC_BUILD && CC_DEBUG,
* "build in release mode": CC_BUILD && !CC_DEBUG,
* }
*
* @module GLOBAL-MACROS
*/
/**
* @property {Boolean} CC_EDITOR - Running in the editor.
*/
/**
* @property {Boolean} CC_PREVIEW - Preview in browser or simulator.
*/
/**
* @property {Boolean} CC_DEV - Running in the editor or preview.
*/
/**
* @property {Boolean} CC_DEBUG - Running in the editor or preview, or build in debug mode.
*/
/**
* @property {Boolean} CC_BUILD - Running in published project.
*/
/**
* @property {Boolean} CC_JSB - Running in native platform (mobile app, desktop app, or simulator).
*/
/**
* @property {Boolean} CC_TEST - Running in the engine's unit test.
*/
/**
* @property {Boolean} CC_RUNTIME - Running in runtime environments.
*/
// window may be undefined when first load engine from editor
var _global = typeof window === 'undefined' ? global : window;
//再次声明一个_global 没关系，最终都指向了global 作为这个js的局部变量用【指向全局的global】
/*
* @param defaultValue - The default value is only used in the editor or preview.
*/
/* 在global下面添加默认变量的值：定义全局宏
主要有下面几个，具体说明在下面进行列出
CC_DEV
CC_DEBUG
CC_JSB
CC_NATIVERENDERER
CC_SUPPORT_JIT
CC_PHYSICS_BUILTIN
CC_PHYSICS_CANNON
CC_EDITOR
CC_PREVIEW
CC_TEST
CC_RUNTIME
CC_JSB
*/
function defineMacro (name, defaultValue) {
// if "global_defs" not preprocessed by uglify, just declare them globally,
// this may happened in release version's preview page.
if (typeof _global[name] === 'undefined') {
_global[name] = defaultValue;
}
}
/* 以下进行数据绑定，当获取name位某个平台的时候 进行提示输出 */
/*
这里会在都require完事后，才会执行，此时CCDebug已经初始化，所以cc.warnID可以用。
index.js里面require('./cocos2d/core/predefine');
-->require('./asset-manager');--->require('./deprecated');--->require('../CCDirector');-->const game = require('./CCGame');
--->const debug = require('./CCDebug');
的过程里面会require
这里的require顺序可以不用太关注。
*/
function defineDeprecatedMacroGetter (name, defaultValue) {
if (typeof _global[name] === 'undefined') {
Object.defineProperty(_global, name, {
get: function () {
let recommandedUsage;
if (name === 'CC_WECHATGAMESUB') {
recommandedUsage = 'cc.sys.platform === cc.sys.WECHAT_GAME_SUB';
}
else if (name === 'CC_WECHATGAME') {
recommandedUsage = 'cc.sys.platform === cc.sys.WECHAT_GAME';
}
else if (name === 'CC_QQPLAY') {
recommandedUsage = 'cc.sys.platform === cc.sys.QQ_PLAY';
}
cc.warnID(1400, name, recommandedUsage);
return defaultValue;
}
});
}
}
function defined (name) {
return typeof _global[name] === 'object';
}
// ensure CC_BUILD is defined
// should not use window.CC_BUILD because we need get global_defs defined in uglify
defineMacro('CC_BUILD', false);
// These default values can only be defined after building
// If you need to modify them
// please modify the `global_defs` in the option returned by `gulp/util/utils.js: getUglifyOptions`.
/*
设置多个编译宏，在构建的时候进行裁剪代码用的
*/
/* 拓展执行说明：
defined('jsb') 具体执行 typeof jsb === 'object' 是否为 true
*/
if (CC_BUILD) {
_global.CC_BUILD = CC_BUILD;
_global.CC_DEV = CC_DEV;
_global.CC_DEBUG = CC_DEBUG;
_global.CC_JSB = CC_JSB;
_global.CC_NATIVERENDERER = CC_NATIVERENDERER;
_global.CC_SUPPORT_JIT = CC_SUPPORT_JIT;
_global.CC_PHYSICS_BUILTIN = CC_PHYSICS_BUILTIN;
_global.CC_PHYSICS_CANNON = CC_PHYSICS_CANNON;
_global.CC_EDITOR = CC_EDITOR;
_global.CC_PREVIEW = CC_PREVIEW;
_global.CC_TEST = CC_TEST;
_global.CC_RUNTIME = CC_RUNTIME;
_global.CC_JSB = CC_JSB;
}
else {//这里定义的宏都是 bool类型
defineMacro('CC_DEV', true); //编辑器 或 预览 // (CC_EDITOR && !CC_BUILD) || CC_PREVIEW || CC_TEST
defineMacro('CC_DEBUG', true);//编辑器 或 预览 或者debug模式的build // CC_DEV || Debug Build
defineMacro('CC_JSB', defined('jsb'));//CC_JSB 来判断是否为 native 环境 了解和机器的桥接jsb==在本机平台（移动应用程序、桌面应用程序或模拟器）上运行
defineMacro('CC_NATIVERENDERER', defined('jsb'));//
defineMacro('CC_SUPPORT_JIT', true);//是否支持jit
defineMacro('CC_PHYSICS_BUILTIN', false);//物理引擎相关
defineMacro('CC_PHYSICS_CANNON', true);//物理引擎相关
defineMacro('CC_EDITOR', defined('Editor') && defined('process') && ('electron' in process.versions));//编辑器内部
defineMacro('CC_PREVIEW', !CC_EDITOR);//预览模式，
defineMacro('CC_TEST', defined('tap') || defined('QUnit'));//单元测试
defineMacro('CC_RUNTIME', 'function' === typeof loadRuntime);//在runtime环境中运行
defineMacro('CC_JSB', defined('jsb') && !CC_RUNTIME);//为什么重复定义了一个CC_JSB ？？？不知道为啥欢迎补充
}
/*
定义几个宏判断是微信 或者qqplay平台
*/
// deprecated
const WECHATGAMESUB = !!(defined('wx') && wx.getSharedCanvas);
const WECHATGAME = !!(defined('wx') && (wx.getSystemInfoSync || wx.getSharedCanvas));
const QQPLAY = defined('bk');
defineDeprecatedMacroGetter('CC_WECHATGAMESUB', WECHATGAMESUB);
/*
宏定义微信平台 CC_WECHATGAME
*/
defineDeprecatedMacroGetter('CC_WECHATGAME', WECHATGAME);
defineDeprecatedMacroGetter('CC_QQPLAY', QQPLAY);
if (CC_DEV) {
/**
* contains internal apis for unit tests
* @expose
*/
cc._Test = {};
}
/**
* @module cc
*/
/**
* The current version of Cocos2d being used.<br/>
* Please DO NOT remove this String, it is an important flag for bug tracking.<br/>
* If you post a bug to forum, please attach this flag.
* @property {String} ENGINE_VERSION
* 定义引擎版本号
*/
const engineVersion = '2.4.1';
_global['CocosEngine'] = cc.ENGINE_VERSION = engineVersion;