24. cc.Director与资源加载策略

1. cc.Director对象

游戏里面控制管理整个游戏全局对象,包括了场景切换等,为cc.Director对象;
导演对象全局只有一个cc.director,大写的为类, 小写的cc.director为全局的导演对象;
cc.director来获取导演对象实例;
游戏中各种管理对象都可以通过cc.director获取,比如物理引擎管理,Action管理, 碰撞检测管理等;

 

2. 常用接口

getWinSize: 适配后的逻辑大小;
getWinSizeInPixels: 获取窗口的像素大小;
getScene: 获取当前的逻辑场景,场景对象下面是Canvas;
setDisplayStats: 是否显示左下角FPS信息;
getCollisionManager: 获取碰撞检测管理对象;
getPhysicsManager :获取物理引擎管理对象;
loadScene(scene_name):加载场景,场景的名字,系统会加载对应的场景
preloadScene(scene_name):预加载场景

 

3. 资源加载策略

h5资源加载的过程:
    (1)从服务器上下载来来资源,并把资源加载到内存中,所以你在做h5游戏,你要把你当前游戏中要用到的资源先加载下来,否者的话,你在运行的时候去加载就来不及了(h5卡住);
三种资源加载策略:
 1>: h5的小游戏:采用全部提前绑定好所有的资源。编写预加载脚本preload.js,
将要加载的资源手动关联到第一个启动的场景上面;
 2>: 添加等待界面,预加载下一个场景,然后再进行切换,提前关联好下一个场景要的资源;    
       cc.loader.onProgress = function ( completedCount, totalCount,  item ){
            console.log("completedCount:" + completedCount + ",totalCount:" + totalCount );
        };
 3>  嫌手动关联麻烦,在场景切换中加入过渡场景,代码来加载场景的资源:    
        cc.loader.loadResAll("textures", function (err, assets) {
        });
   代码加载资源会导致setting.js文件过大,一般尽量少在代码里面加载资源;

 

例子

home_scene.js

// Learn cc.Class:
//  - [Chinese] https://docs.cocos.com/creator/manual/zh/scripting/class.html
//  - [English] http://docs.cocos2d-x.org/creator/manual/en/scripting/class.html
// Learn Attribute:
//  - [Chinese] https://docs.cocos.com/creator/manual/zh/scripting/reference/attributes.html
//  - [English] http://docs.cocos2d-x.org/creator/manual/en/scripting/reference/attributes.html
// Learn life-cycle callbacks:
//  - [Chinese] https://docs.cocos.com/creator/manual/zh/scripting/life-cycle-callbacks.html
//  - [English] https://www.cocos2d-x.org/docs/creator/manual/en/scripting/life-cycle-callbacks.html

cc.Class({
    extends: cc.Component,

    properties: {
        // foo: {
        //     // ATTRIBUTES:
        //     default: null,        // The default value will be used only when the component attaching
        //                           // to a node for the first time
        //     type: cc.SpriteFrame, // optional, default is typeof default
        //     serializable: true,   // optional, default is true
        // },
        // bar: {
        //     get () {
        //         return this._bar;
        //     },
        //     set (value) {
        //         this._bar = value;
        //     }
        // },

        wait: {
            default: null,
            type: cc.Node,
        },

        progress_lable: {
            type: cc.Label,
            default: null,
        },

    },

    // LIFE-CYCLE CALLBACKS:

    onLoad () {

        this.wait.active = false;
        this.progress_lable.string = "0%";

    },

    start () {

    },

    goto_road: function() {
        
        //切换场景时如果直接切换过去,下一个场景会加载资源等待加载的时候会卡住一段时间
        //我们在这里加上等待界面
        this.wait.active = true;

        //预加载
        cc.director.preloadScene("roadmap_scene", function(completedCount, totalCount, item) {
                                    console.log("completedCount:" + completedCount + ",totalCount:" + totalCount);
                                    var per = Math.floor(completedCount * 100 / totalCount);
                                    this.progress_lable.string = per + "%";
                                }.bind(this), function() {
                                    cc.director.loadScene("roadmap_scene");
                                });
        //end
    
    },

    // update (dt) {},
});

preload.js

// Learn cc.Class:
//  - [Chinese] https://docs.cocos.com/creator/manual/zh/scripting/class.html
//  - [English] http://docs.cocos2d-x.org/creator/manual/en/scripting/class.html
// Learn Attribute:
//  - [Chinese] https://docs.cocos.com/creator/manual/zh/scripting/reference/attributes.html
//  - [English] http://docs.cocos2d-x.org/creator/manual/en/scripting/reference/attributes.html
// Learn life-cycle callbacks:
//  - [Chinese] https://docs.cocos.com/creator/manual/zh/scripting/life-cycle-callbacks.html
//  - [English] https://www.cocos2d-x.org/docs/creator/manual/en/scripting/life-cycle-callbacks.html

cc.Class({
    extends: cc.Component,

    properties: {
        // foo: {
        //     // ATTRIBUTES:
        //     default: null,        // The default value will be used only when the component attaching
        //                           // to a node for the first time
        //     type: cc.SpriteFrame, // optional, default is typeof default
        //     serializable: true,   // optional, default is true
        // },
        // bar: {
        //     get () {
        //         return this._bar;
        //     },
        //     set (value) {
        //         this._bar = value;
        //     }
        // },

        //预加载资源
        img_array: {
            default: [],
            type: cc.SpriteFrame,
        },
        atlas_array: { //图集资源
            default: [],
            type: cc.SpriteAtlas,
        },
        sound_array: {
            default: [],
            url: cc.AudioClip,
        },
        prefab_array: { //预制体资源
            default: [],
            type: cc.Prefab,
        },

    },

    // LIFE-CYCLE CALLBACKS:

    // onLoad () {},

    start () {

    },

    // update (dt) {},
});

工程截图

24. cc.Director与资源加载策略_第1张图片

24. cc.Director与资源加载策略_第2张图片 

 

 

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