cocos2d-js 3.0 RC0 手动绑定 C++调用js,js调用C++ jsbinding

参考:http://www.tairan.com/archives/4902

参考文章是2.x版本的,对于3.0也许不合适了,没有深究。

代码:https://github.com/kenkozheng/cocos2d-js/tree/master/jsbinding(cpp_js%20js_cpp)

 

1 JS调用C++

3.0中写这个绑定比较简单,跟ANE调用java如出一辙,一个JSContext,一个jsval,使用cocos2d提供的c++和js变量转换的函数做好转换即可。

cocos2d-js原来就定义好了代码风格:

    sc->addRegisterCallback(MinXmlHttpRequest::_js_register); 

    sc->addRegisterCallback(register_jsb_websocket); 

    sc->addRegisterCallback(register_jsb_socketio); 

    

    #if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID) 

    sc->addRegisterCallback(JavascriptJavaBridge::_js_register); 

    #endif 

    

    sc->addRegisterCallback(register_jsb_kenko_all); 

    

    sc->start();

我们也顺着这个风格,添加一个函数:register_jsb_kenko_all,这是一个全局函数。

jsb_kenko_auto.h



#ifndef jsb_jsb_kenko_auto_h 

#define jsb_jsb_kenko_auto_h



#include "cocos2d.h"



std::string os_info(); 

bool jsb_os_info(JSContext *cx, uint32_t argc, JS::Value *vp); 

bool jsb_callback(JSContext *cx, uint32_t argc, JS::Value *vp); 

void register_jsb_kenko_all(JSContext* cx, JSObject* obj);



#endif
jsb_kenko_auto.cpp



#include "jsb_kenko_auto.h" 

#include "cocos2d_specifics.hpp"



std::string os_info() { 

    CCLOG("it's c++ os_info here"); 

    return "os_info"; 

}



  

bool jsb_os_info(JSContext *cx, uint32_t argc, JS::Value *vp) { 

    jsval ret = std_string_to_jsval(cx, os_info()); 

    JS_SET_RVAL(cx, vp, ret); 

  

    return true; 

} 

  

void register_jsb_kenko_all(JSContext *cx, JSObject *obj) { 

    JS_DefineFunction(cx, obj, "osInfo", jsb_os_info, 0, 0);  //生成名为osInfo的js全局函数
}

 

把h和cpp文件都放到AppDelegate.cpp同一个地方。上述的c++代码会在spidermonkey运行环境中生成相应的js接口,所以,我们不需要自己额外写对应的js接口。

然后就可以写js代码试试了。从运行结果可以看到,js调用成功,并获取到返回值。

cc.game.onStart = function(){ 

    cc.view.setDesignResolutionSize(800, 450, cc.ResolutionPolicy.SHOW_ALL); 

    cc.view.resizeWithBrowserSize(true); 

    cc.director.runScene(new MainScene()); 

    

    cc.log("js get from c++: " + osInfo()); 

}; 

cc.game.run();

 

cocos2d-js 3.0 RC0 手动绑定 C++调用js,js调用C++ jsbinding

 

2 C++回调

关键在于使用ScriptingCore提供的方法,调用js。首先来看看ScriptingCore的源代码,都有些什么方法可以用。

executeFunctionWithOwner可以实现类似cc.sprite之类的c++对象和js对象的调用,没有深究。这里演示的是如何做全局调用。

evalString对任何一个前端开发来说都不会太陌生,毕竟这里不是浏览器,排除各种乱七八糟的安全问题,我们直接用这个函数。

    

/** 

     @brief Execute a scripted global function. 

     @brief The function should not take any parameters and should return an integer. 

     @param functionName String object holding the name of the function, in the global script environment, that is to be executed. 

     @return The integer value returned from the script function. 

     */ 

    virtual int executeGlobalFunction(const char* functionName) { return 0; }



    virtual int sendEvent(cocos2d::ScriptEvent* message) override; 

    

    virtual bool parseConfig(ConfigType type, const std::string& str) override;



    virtual bool handleAssert(const char *msg) { return false; }



    virtual void setCalledFromScript(bool callFromScript) { _callFromScript = callFromScript; }; 

    virtual bool isCalledFromScript() { return _callFromScript; }; 

    

    bool executeFunctionWithObjectData(void* nativeObj, const char *name, JSObject *obj); 

    bool executeFunctionWithOwner(jsval owner, const char *name, uint32_t argc = 0, jsval* vp = NULL, jsval* retVal = NULL);



    void executeJSFunctionWithThisObj(jsval thisObj, jsval callback, uint32_t argc = 0, jsval* vp = NULL, jsval* retVal = NULL);



    /** 

     * will eval the specified string 

     * @param string The string with the javascript code to be evaluated 

     * @param outVal The jsval that will hold the return value of the evaluation. 

     * Can be NULL. 

     */ 

    bool evalString(const char *string, jsval *outVal, const char *filename = NULL, JSContext* cx = NULL, JSObject* global = NULL);

 

修改jsb_kenko_auto.cpp:

#include "jsb_kenko_auto.h" 

#include "cocos2d_specifics.hpp"



std::string os_info() { 

    CCLOG("it's c++ os_info here"); 

    return "os_info"; 

}



bool jsb_callback(JSContext *cx, uint32_t argc, JS::Value *vp) { 

    CCLOG("it's c++ testCallback here"); 

    JSContext* jc = ScriptingCore::getInstance()->getGlobalContext(); 

    // 注释部分适合有对象化的调用 

    // 参考:http://www.tairan.com/archives/4902 

    //jsval v[2]; 

    //v[0] = int32_to_jsval(jc, 32); 

    //v[1] = int32_to_jsval(jc, 12); 

    

    // 通过 ScriptingCore 封装好的方法实现回调,可以帮助我们节省很多细节上的研究 

    //js_proxy_t * p = jsb_get_native_proxy(); 

    //return ScriptingCore::getInstance()->executeFunctionWithOwner(OBJECT_TO_JSVAL(p->obj), "cpp_callback", 2, v);        //2是参数个数,v是参数列表 

    

    //找到一个更适合全局函数的方法 

    jsval ret; 

    return ScriptingCore::getInstance()->evalString("cpp_callback(2,3)", &ret); 

} 

  

bool jsb_os_info(JSContext *cx, uint32_t argc, JS::Value *vp) { 

    jsval ret = std_string_to_jsval(cx, os_info()); 

    JS_SET_RVAL(cx, vp, ret); 

  

    return true; 

} 

  

void register_jsb_kenko_all(JSContext *cx, JSObject *obj) { 

    JS_DefineFunction(cx, obj, "osInfo", jsb_os_info, 0, 0);  

    JS_DefineFunction(cx, obj, "test_cpp_callback", jsb_callback, 0, 0);  

}

 

相应在js侧添加一个全局函数,给c++调用。

cc.game.onStart = function(){ 

    cc.view.setDesignResolutionSize(800, 450, cc.ResolutionPolicy.SHOW_ALL); 

    cc.view.resizeWithBrowserSize(true); 

    cc.director.runScene(new MainScene()); 

    

    cc.log("js get from c++: " + osInfo()); 

    test_cpp_callback(); 

}; 

cc.game.run();



function cpp_callback(a, b) { 

    cc.log("cpp return two integer: " + a + " " + b); 

}

 

看输出结果:

  cocos2d-js 3.0 RC0 手动绑定 C++调用js,js调用C++ jsbinding

 

3 各种变量转换函数

都在js_manual_conversions.h这里了,真是应有尽有。下边只列出一部分。

bool jsval_to_ushort( JSContext *cx, jsval vp, unsigned short *ret ); 

bool jsval_to_int32( JSContext *cx, jsval vp, int32_t *ret ); 

bool jsval_to_uint32( JSContext *cx, jsval vp, uint32_t *ret ); 

bool jsval_to_uint16( JSContext *cx, jsval vp, uint16_t *ret ); 

bool jsval_to_long( JSContext *cx, jsval vp, long *out); 

bool jsval_to_ulong( JSContext *cx, jsval vp, unsigned long *out); 

bool jsval_to_long_long(JSContext *cx, jsval v, long long* ret); 

bool jsval_to_std_string(JSContext *cx, jsval v, std::string* ret);



jsval int32_to_jsval( JSContext *cx, int32_t l); 

jsval uint32_to_jsval( JSContext *cx, uint32_t number ); 

jsval ushort_to_jsval( JSContext *cx, unsigned short number ); 

jsval long_to_jsval( JSContext *cx, long number ); 

jsval ulong_to_jsval(JSContext* cx, unsigned long v); 

jsval long_long_to_jsval(JSContext* cx, long long v); 

jsval std_string_to_jsval(JSContext* cx, const std::string& v);

 

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