cocos-js,内存管理方式
一.开篇引题在理解cocos2dx的内存管理机制之前,我们可以先了解下c++中变量的内存空间的分配问题.
问题来了,cocos2dx如何管理内存:
二.示例讲解1.c++代码示例//对象创建的时候引用计数被设置为1,这个是在它的构造函数中完成的,它会先调用父类Ref的构造函数 //Ref::Ref() //: _referenceCount(1) Node * node = new Node(); ("retain count:%d",node->getReferenceCount()); //调用retain方法的时候引用计数增加1 node->retain(); log("retain count:%d",node->getReferenceCount()); //调用release方法的时候引用计数减1,当这个引用计数减为0的时候,在release方法中会delete掉这个对象 node->release(); log("retain count:%d",node->getReferenceCount()); //当我们调用autorelease方法的时候会调用这段代码 //PoolManager::getInstance()->getCurrentPool()->addObject(this); //调用autorelease方法的时候对象会被放到自动回收池中,这个自动回收池在每帧结束的时候会调用一次对象的release方法 node->autorelease(); log("retain count:%d",node->getReferenceCount());
void DisplayLinkDirector::mainLoop() { if (_purgeDirectorInNextLoop) { _purgeDirectorInNextLoop = false; purgeDirector(); } else if (_restartDirectorInNextLoop) { _restartDirectorInNextLoop = false; restartDirector(); } else if (! _invalid) { drawScene(); // release the objects PoolManager::getInstance()->getCurrentPool()->clear(); } } void AutoreleasePool::clear() { #if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0) _isClearing = true; #endif std::vector<Ref*> releasings; releasings.swap(_managedObjectArray); for (const auto &obj : releasings) { obj->release(); } #if defined(COCOS2D_DEBUG) && (COCOS2D_DEBUG > 0) _isClearing = false; #endif } 下面我们来看一下,通常我们的代码都是怎么写的,来看看这个自动回收机制怎么就做到自动回收了! //在create的时候调用了sprite的autorelease方法 CCSprite * sprite = CCSprite::create("HelloWorld.png"); CCLog("retain count:%d",sprite->getReferenceCount()); //retain 1 this->addChild(sprite); CCLog("retain count:%d",sprite->getReferenceCount()); //retain 2
Node * Node::create() { Node * ret = new (std::nothrow) Node(); if (ret && ret->init()) { ret->autorelease(); } else { CC_SAFE_DELETE(ret); } return ret; } 有可能有的人又会问,在new 一个node后可不可以就让它的引用计数为0,而不需要调用autorelease方法呢? 我们再来看下addChild时引用计数+1,removeChild时引用计数-1相关的代码: 在addChild方法里有一句this->insertChild(child,localZOrder); 在insertChild方法里有一句_children.pushBack(child); 最后在pushBack方法里: void pushBack(T object) { CCASSERT(object != nullptr,"The object should not be nullptr"); _data.push_back( object ); object->retain(); } 2.JS代码示例我们先来看JS的模板工程代码: var HelloWorldLayer = cc.Layer.extend({ sprite:null,ctor:function () { ////////////////////////////// // 1. super init first this._super(); ///////////////////////////// // 2. add a menu item with "X" image,which is clicked to quit the program // you may modify it. // ask the window size var size = cc.winSize; // add a "close" icon to exit the progress. it's an autorelease object var closeItem = new cc.MenuItemImage( res.CloseNormal_png,res.CloseSelected_png,function () { cc.log("wade getReferenceCount1:"+helloLabel.getReferenceCount()) cc.log("wade getReferenceCount2:"+this.sprite.getReferenceCount()) },this); closeItem.attr({ x: size.width - 20,y: 20,anchorX: 0.5,anchorY: 0.5 }); var menu = new cc.Menu(closeItem); menu.x = 0; menu.y = 0; this.addChild(menu,1); ///////////////////////////// // 3. add your codes below... // add a label shows "Hello World" // create and initialize a label // var helloLabel = new cc.LabelTTF("Hello World","Arial",38); var helloLabel = cc.LabelTTF.create("Hello World",38); // position the label on the center of the screen helloLabel.x = size.width / 2; helloLabel.y = size.height / 2 + 200; // add the label as a child to this layer this.addChild(helloLabel,5); cc.log("wade getReferenceCount1:"+helloLabel.getReferenceCount()) // add "HelloWorld" splash screen" this.sprite = new cc.Sprite(res.HelloWorld_png); this.sprite.attr({ x: size.width / 2,y: size.height / 2 }); this.addChild(this.sprite,0); cc.log("wade getReferenceCount2:"+this.sprite.getReferenceCount()) return true; } }); getReferenceCount这个方法就是获取引用计数的,在 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |