Cocos2dx-jsb 3.x 精灵构建过程浅析:
1、我们在使用精灵是一般类似于下面这样:
this.sprite = new cc.Sprite(res.HelloWorld_png);
this.addChild(this.sprite,0);
我们知道这样用,但是调用过程是怎样的呢?
2、调用过程:
会先调用C++端的:
booljs_cocos2dx_Sprite_constructor(JSContext *cx,uint32_t argc,jsval *vp)
{
JS::CallArgs args =JS::CallArgsFromVp(argc,vp);
bool ok = true; //创建了C++中精灵对象
cocos2d::Sprite* cobj = new (std::nothrow)cocos2d::Sprite();
cocos2d::Ref *_ccobj =dynamic_cast<cocos2d::Ref *>(cobj);
if (_ccobj) {
_ccobj->autorelease();
}
//JSObject *obj = JS_NewObject(cx,typeClass->jsclass,typeClass->proto,typeClass->parentProto);
JS::RootedObject proto(cx,typeClass->proto.get());
JS::RootedObject parent(cx,typeClass->parentProto.get());
JS::RootedObject obj(cx,JS_NewObject(cx,proto,parent));
args.rval().set(OBJECT_TO_JSVAL(obj));
// link the native object with thejavascript object 把C++ 和javascrip中的对象绑定,具体不太清楚
js_proxy_t* p = jsb_new_proxy(cobj,obj);
AddNamedObjectRoot(cx,&p->obj,"cocos2d::Sprite");
//调用_ctor方法,这个方法在哪里呢?在cocos提供的script文件夹下有个jsb_create_apis.js文件,这里面有我们需要的函数:
if (JS_HasProperty(cx,obj,"_ctor",&ok) && ok)
ScriptingCore::getInstance()->executeFunctionWithOwner(OBJECT_TO_JSVAL(obj),args);
return true;
}
3、下面这段,就是有关精灵调用的部分,看到了吧,这个函数,会根据创建精灵时传入
newcc.Sprite(res.HelloWorld_png);的参数,调用不同的initXXXX方法,
/************************ Sprite*************************/
//这里有一点还没搞明白,就是fileName,rect这个参数怎么从C++端传到JavaScript端的,后面在研究。
_p =cc.Sprite.prototype;
_p._ctor =function(fileName,rect) {
if (fileName === undefined) {
cc.Sprite.prototype.init.call(this);
}
else if (typeof(fileName) ==="string") {
if (fileName[0] === "#") {
//init with a sprite frame name
var frameName = fileName.substr(1,fileName.length - 1);
this.initWithSpriteFrameName(frameName);
} else {
// Create with filename and rect
rect ? this.initWithFile(fileName,rect) : this.initWithFile(fileName);
}
}
else if (typeof(fileName) ==="object") {
if (fileName instanceof cc.Texture2D) {
//init with texture and rect
rect ?this.initWithTexture(fileName,rect) : this.initWithTexture(fileName);
} else if (fileName instanceofcc.SpriteFrame) {
//init with a sprite frame
this.initWithSpriteFrame(fileName);
}
}
};
总:其他很多类也是通过这种方法处理的,流程跟这个差不多。
参考文章:http://www.cocos2d-x.org/docs/manual/framework/html5/v3/inheritance/zh