c++与lua

lua提供了很多c api是的lua与c可以非常方便的交互然而实际运用的交互是需要使用c++ java objc等语言来与lua交互实现功能，

在cocos 将c++类注册到lua 主要关心将类对象实例化函数注册给lua以及实例对象的函数注册到lua， 将类对象注册为usertype，将函数注册在类module下

DEMO CODE

// 以c编译模式引入tolua++#ifdef __cplusplusextern "C" {#endif#include "tolua++.h"#ifdef __cplusplus}#endifTOLUA_API int register_test_binding(lua_State* tolua_S);// 定义好的c++类以及他的public函数注册给luaclass DrawNode3D: public Node{public:    static DrawNode3D* create();    void drawLine(const Vec3 &from, const Vec3 &to, const Color4F &color);    void drawCube(Vec3* vertices, const Color4F &color);    const BlendFunc& getBlendFunc() const;    void setBlendFunc(const BlendFunc &blendFunc);    void onDraw(const Mat4 &transform, uint32_t flags);};int lua_cocos2dx_DrawNode3D_getBlendFunc(lua_State* L){    int argc = 0;    cocos2d::DrawNode3D* cobj = nullptr;    bool ok  = true;#if COCOS2D_DEBUG >= 1    tolua_Error tolua_err;#endif#if COCOS2D_DEBUG >= 1// 校验 drawNode 的usertype是否在栈底    if (!tolua_isusertype(L,1,"cc.DrawNode3D",0,&tolua_err)) goto tolua_lerror;#endif    // 将栈底的userType 转化为 c++的drawNode对象指针    cobj = (cocos2d::DrawNode3D*)tolua_tousertype(L,1,0);#if COCOS2D_DEBUG >= 1    if (!cobj)    {        tolua_error(L,"invalid 'cobj' in function 'lua_cocos2dx_DrawNode3D_getBlendFunc'", nullptr);        return 0;    }#endif    // 获取栈的长度也就是参数长度    argc = lua_gettop(L)-1;    if (argc == 0)    {        if(!ok)            return 0;        // 执行c++函数        const cocos2d::BlendFunc& ret = cobj->getBlendFunc();        // 压入栈道lua        blendfunc_to_luaval(L, ret);        return 1;    }    CCLOG("%s has wrong number of arguments: %d, was expecting %d \n", "cc.DrawNode3D:getBlendFunc",argc, 0);    return 0;#if COCOS2D_DEBUG >= 1tolua_lerror:    tolua_error(L,"#ferror in function 'lua_cocos2dx_DrawNode3D_getBlendFunc'.",&tolua_err);#endif    return 0;}int lua_cocos2dx_DrawNode3D_create(lua_State* L){    int argc = 0;    bool ok  = true;#if COCOS2D_DEBUG >= 1    tolua_Error tolua_err;#endif#if COCOS2D_DEBUG >= 1    // 检查栈底类型    if (!tolua_isusertable(L,1,"cc.DrawNode3D",0,&tolua_err)) goto tolua_lerror;#endif    argc = lua_gettop(L) - 1;    //检查参数数量    if (argc == 0)    {        if(!ok)            return 0;        //创建c++对象        cocos2d::DrawNode3D* ret = cocos2d::DrawNode3D::create();        //将对象压栈给lua        object_to_luaval<cocos2d::DrawNode3D>(L, "cc.DrawNode3D",(cocos2d::DrawNode3D*)ret);        return 1;    }    CCLOG("%s has wrong number of arguments: %d, was expecting %d\n ", "cc.DrawNode3D:create",argc, 0);    return 0;#if COCOS2D_DEBUG >= 1tolua_lerror:    tolua_error(L,"#ferror in function 'lua_cocos2dx_DrawNode3D_create'.",&tolua_err);#endif    return 0;}int lua_cocos2dx_DrawNode3D_setBlendFunc(lua_State* L){    int argc = 0;    cocos2d::DrawNode3D* cobj = nullptr;    bool ok = true;#if COCOS2D_DEBUG >= 1    tolua_Error tolua_err;#endif#if COCOS2D_DEBUG >= 1    if (!tolua_isusertype(L,1,"cc.DrawNode3D",0,&tolua_err)) goto tolua_lerror;#endif    //获取到lua中的c++对象指针    cobj = (cocos2d::DrawNode3D*)tolua_tousertype(L,1,0);#if COCOS2D_DEBUG >= 1    if (!cobj)    {        // 如果对象被释放了会向lua报错        tolua_error(L,"invalid 'cobj' in function 'lua_cocos2dx_DrawNode3D_setBlendFunc'", nullptr);        return 0;    }#endif    // 检测参数数量    argc = lua_gettop(L)-1;    if (argc == 1)    {        cocos2d::BlendFunc arg0;        ok &= luaval_to_blendfunc(L, 2, &arg0, "cc.Sprite3D:setBlendFunc");        if(!ok)        {            tolua_error(L,"invalid arguments in function 'lua_cocos2dx_DrawNode3D_setBlendFunc'", nullptr);            return 0;        }        // 执行对象函数        cobj->setBlendFunc(arg0);        return 0;    }    CCLOG("%s has wrong number of arguments: %d, was expecting %d \n", "cc.DrawNode3D:setBlendFunc",argc, 1);    return 0;#if COCOS2D_DEBUG >= 1tolua_lerror:    tolua_error(L,"#ferror in function 'lua_cocos2dx_DrawNode3D_setBlendFunc'.",&tolua_err);#endif    return 0;}int lua_register_cocos2dx_DrawNode3D(lua_State* L){    // 创建cc.DrawNode3D lua userType    tolua_usertype(L,"cc.DrawNode3D");    // 注册为cc在lua的类    tolua_cclass(L,"DrawNode3D","cc.DrawNode3D","cc.Node",nullptr);    // 开启drawNode module    tolua_beginmodule(L,"DrawNode3D");    //依次想drawNode 添加成员函数    tolua_function(L,"getBlendFunc",lua_cocos2dx_DrawNode3D_getBlendFunc);    tolua_function(L,"setBlendFunc",lua_cocos2dx_DrawNode3D_setBlendFunc01);    tolua_function(L,"drawLine",lua_cocos2dx_DrawNode3D_drawLine);    tolua_function(L,"clear",lua_cocos2dx_DrawNode3D_clear);    tolua_function(L,"drawCube",lua_cocos2dx_DrawNode3D_drawCube);    tolua_function(L,"create", lua_cocos2dx_DrawNode3D_create);    // 关闭drawNode module    tolua_endmodule(L);    std::string typeName = typeid(cocos2d::DrawNode3D).name();    g_luaType[typeName] = "cc.DrawNode3D";    g_typeCast["DrawNode3D"] = "cc.DrawNode3D";    return 1;}int register_test_binding(lua_State* L){    //开lua栈     tolua_open(L);    //开启cc module 如果存在则不会创建拿旧的    tolua_module(L, "cc", 0);    // 开始module下的成员添加    tolua_beginmodule(L, "cc");    // 注册drawNode    lua_register_cocos2dx_DrawNode3D(L);    // module成员添加    tolua_endmodule(L);    return 0;}