cocos2dx-详细剖析lua(如何与lua集成,如何导出lua api,如何与lua交互)
本文详解lua是怎么跟c/c++交互的；cocos怎么利用luac/c++交互的技术，导出lua api的供脚本使用；cocos如何进行c++与lua混合编程，cocos有哪些重要lua接口。
一、lua与c、c++的交互
1、lua简介
lua是由c语言编写，c/c++程序可以包含lua库，利用提供的api进行lua脚本开发，lua提供了c与lua相互调用的接口。下面是lua的全部库文件：
lapi.c ldo.h lmathlib.c lstate.c lua.h
lapi.h ldump.c lmem.c lstate.h luaconf.h
lauxlib.c lfunc.c lmem.hlstring.clualib.h
lauxlib.h lfunc.h loadlib.clstring.hlundump.c
lbaselib.c lgc.c lobject.clstrlib.clundump.h
lcode.c lgc.h lobject.h ltable.c lvm.c
lcode.h linit.c lopcodes.c ltable.h lvm.h
ldblib.c liolib.c lopcodes.hltablib.clzio.c
ldebug.c llex.c loslib.cltm.clzio.h
ldebug.h llex.h lparser.cltm.hprint.c
ldo.c llimits.h lparser.h lua.c这些文件中lua_开头的api是c api，luaL_开头的是auxiliary library，其它的是Lua functions
2、c、c++调用lua
可以利用lua编写一些代码，然后供c++调用，可以用lua编写配置文件，从中提取信息。下面是lua代码，描述了app的配置信息以及一个测试函数：
-- app config
config = {
version = "1.0",
name = "myApp",
date = "2016/6/25"
author = "lewis"
}
-- for function test
function add(x, y)
return x + y
endvoid LuaTest::btnClick_c_call_lua(CCObject* pSender, CCControlEvent event){
//创建Lua状态机
lua_State *L = luaL_newstate();
//加载并执行Lua文件
string path = CCFileUtils::sharedFileUtils()->fullPathForFilename("config.lua");
if(luaL_dofile(L, path.c_str()))
{
cout<<"luaL_dofile error"<version=1.0
name=myApp
date=2016/6/25
author=lewis
10 + 20 = 30.0000003、lua调用c、c++
lua调用c，所提供的c函数签名必需是typedef int (*lua_CFunction) (lua_State *L);这种类型。编写好函数后，只需向lua的lua_State L注册一下就OK了，之后使用L执行的lua代码都可以访问在L注册的c函数。看上面定义，好像lua函数不好传参数给c函数啊！其实你可以在lua函数传任意参数，它会写到L的栈中，前面曾说过c与lua是通过一个栈通信的。
当lua函数带调用提供了N个参数时，lua最终调用的c函数可以通过上面讲的c/c++调用lua里面提供的接口提取出参数，进行计算，最后再把结果push到栈中返回给lua，详细图解如下：
图片地址：http://photo.yupoo.com/lewislufie/FEuF115o/medish.jpg下面是代码，在lua中创建一个CCLabelTTF加到当前场景中。
int cAPI_addLabel(lua_State *L){
printf("stack size:%d\n", lua_gettop(L));
//获得位置x、y
double y = lua_tonumber(L, -1);
double x = lua_tonumber(L, -2);
//create label
CCString *str = CCString::createWithFormat("hello world\n x:%f y%f", x, y);
Label *label = Label::create(str->getCString(), BIG);
label->setPosition(ccp(x, y));
CCDirector::sharedDirector()->getRunningScene()->addChild(label);
lua_pushlightuserdata(L, label);//把指针传给lua
return 1;
}
void LuaTest::btnClick_lua_call_c_2(CCObject* pSender, CCControlEvent event){
//新建状态
lua_State *L = luaL_newstate();
luaL_openlibs(L);//we will use lua io api
//向lua注册c函数
lua_register(L, "cAPI_addLabel", cAPI_addLabel);
//加载并执行脚本
string path = CCFileUtils::sharedFileUtils()->fullPathForFilename("luacallc.lua");
luaL_dofile(L, path.c_str());
//关闭状态
lua_close(L);
}
图片地址：http://photo.yupoo.com/lewislufie/FEv1Q9r7/medish.jpg输出：
stack size:2
result: userdata: 0x7a37c400
local x = cAPI_addLabel(320, 200)
print("result:", x)函数注册后执行lua文件，lua里调用了cAPI_addLabel这个函数，lua首先会把L中的栈清空，然后把参数从左往右压栈，这也是上面x、y的获取是
先double y =lua_tonumber(L, -1);再double x =lua_tonumber(L, -2);因为y在栈顶-1位置，x在下面-2的位置，c函数cAPI_addLabel取出栈中2个元素来设置标签位置。设置完后把标签对象的指针压栈，然后返回1，告诉lua引擎我这个函数返回1个返回值，然后返回到lua代码的执行，它从栈顶往下取1个数给result，最后输出result这个userdata元素的值。这里看出lua个c是如何通过栈交换数据的，c从栈中取数据是我们手动编码，lua从栈中取数据是lua引擎执行的。每次lua调c函数L的栈会清空，然后压入参数这个要注意，获取的返回值个数是根据c函数返回值确定的，这个也要注意下。
二、利器tolua++
1、cocos怎么把tolua++导出的c api给lua调用的
上面的lua调用c/c++已经展示了lua调用c函数并且传参数给它设置cocos对象位置，但是如果我们都这样编码，对于一个cocos当中的类，比如CCSprite有好多个函数，我们要编写符合lua调用的c接口，那得先从栈中取出参数，然后把参数传给对应的c++函数，执行后再把c++的函数结果压栈，这些操作在的cAPI_addLabel函数中可以找到，此外还要进行检查，万一lua那边传来的参数类型不对呢，就得用lua_isTYPE来判断类型，那工程量有点大啊。好在我们有工具tolua++，利用它可以轻松导出c api供lua调用。
下面是CCLabelTTF向lua注册的代码在LuaCocos2d.cpp里面可以找到
tolua_beginmodule(tolua_S,"CCLabelTTF");
tolua_function(tolua_S,"new",tolua_Cocos2d_CCLabelTTF_new00);
tolua_function(tolua_S,"new_local",tolua_Cocos2d_CCLabelTTF_new00_local);
tolua_function(tolua_S,".call",tolua_Cocos2d_CCLabelTTF_new00_local);
tolua_function(tolua_S,"delete",tolua_Cocos2d_CCLabelTTF_delete00);
tolua_function(tolua_S,"init",tolua_Cocos2d_CCLabelTTF_init00);
tolua_function(tolua_S,"setString",tolua_Cocos2d_CCLabelTTF_setString00);
tolua_function(tolua_S,"getString",tolua_Cocos2d_CCLabelTTF_getString00);
tolua_function(tolua_S,"getHorizontalAlignment",tolua_Cocos2d_CCLabelTTF_getHorizontalAlignment00);
tolua_function(tolua_S,"setHorizontalAlignment",tolua_Cocos2d_CCLabelTTF_setHorizontalAlignment00);
tolua_function(tolua_S,"getVerticalAlignment",tolua_Cocos2d_CCLabelTTF_getVerticalAlignment00);
tolua_function(tolua_S,"setVerticalAlignment",tolua_Cocos2d_CCLabelTTF_setVerticalAlignment00);
tolua_function(tolua_S,"getDimensions",tolua_Cocos2d_CCLabelTTF_getDimensions00);
tolua_function(tolua_S,"setDimensions",tolua_Cocos2d_CCLabelTTF_setDimensions00);
tolua_function(tolua_S,"getFontSize",tolua_Cocos2d_CCLabelTTF_getFontSize00);
tolua_function(tolua_S,"setFontSize",tolua_Cocos2d_CCLabelTTF_setFontSize00);
tolua_function(tolua_S,"getFontName",tolua_Cocos2d_CCLabelTTF_getFontName00);
tolua_function(tolua_S,"setFontName",tolua_Cocos2d_CCLabelTTF_setFontName00);
tolua_function(tolua_S,"create",tolua_Cocos2d_CCLabelTTF_create00);
tolua_function(tolua_S,"create",tolua_Cocos2d_CCLabelTTF_create01);
tolua_function(tolua_S,"create",tolua_Cocos2d_CCLabelTTF_create02);
tolua_function(tolua_S,"create",tolua_Cocos2d_CCLabelTTF_create03);
tolua_endmodule(tolua_S);
tolua_beginmodule(tolua_S,"CCLabelTTF");TOLUA_API void tolua_beginmodule (lua_State* L, const char* name)
{
if (name)
{
lua_pushstring(L,name);
lua_rawget(L,-2);
}
else
lua_pushvalue(L,LUA_GLOBALSINDEX);
}lua_pushstring(L,name);压栈，lua_rawget(L,-2)等价于lua_gettable(L, -2)【Similar to lua_settable, but does a raw assignment (i.e., without metamethods).】
这里lua_pushstring后栈中应该一个元素呀，怎么还有-2呢？查看下面代码：
/* Open function */
TOLUA_API int tolua_Cocos2d_open (lua_State* tolua_S)
{
tolua_open(tolua_S);
tolua_reg_types(tolua_S);/* method: create of class CCLabelTTF */
#ifndef TOLUA_DISABLE_tolua_Cocos2d_CCLabelTTF_create03
static int tolua_Cocos2d_CCLabelTTF_create03(lua_State* tolua_S)
{
tolua_Error tolua_err;
if (
!tolua_isusertable(tolua_S,1,"CCLabelTTF",0,&tolua_err) ||
!tolua_isnoobj(tolua_S,2,&tolua_err)
)
goto tolua_lerror;
else
{
{
CCLabelTTF* tolua_ret = (CCLabelTTF*) CCLabelTTF::create();
int nID = (tolua_ret) ? (int)tolua_ret->m_uID : -1;
int* pLuaID = (tolua_ret) ? &tolua_ret->m_nLuaID : NULL;
toluafix_pushusertype_ccobject(tolua_S, nID, pLuaID, (void*)tolua_ret,"CCLabelTTF");
}
}
return 1;
tolua_lerror:
return tolua_Cocos2d_CCLabelTTF_create02(tolua_S);
}
#endif //#ifndef TOLUA_DISABLEtolua_module(tolua_S,NULL,0); tolua_beginmodule(tolua_S,NULL); tolua_cclass(tolua_S,"kmMat4","kmMat4","",NULL); tolua_beginmodule(tolua_S,"kmMat4"); tolua_array(tolua_S,"mat",tolua_get_Cocos2d_kmMat4_mat,tolua_set_Cocos2d_kmMat4_mat); tolua_endmodule(tolua_S); tolua_function(tolua_S,"kmGLFreeAll",tolua_Cocos2d_kmGLFreeAll00); tolua_function(tolua_S,"kmGLPushMatrix",tolua_Cocos2d_kmGLPushMatrix00); tolua_function(tolua_S,"kmGLPopMatrix",tolua_Cocos2d_kmGLPopMatrix00); tolua_function(tolua_S,"kmGLMatrixMode",tolua_Cocos2d_kmGLMatrixMode00); tolua_function(tolua_S,"kmGLLoadIdentity",tolua_Cocos2d_kmGLLoadIdentity00); 上面是注册cocos c代码的函数 tolua_Cocos2d_open，里面有一句 tolua_beginmodule (tolua_S, NULL );代码如下
TOLUA_API void tolua_beginmodule (lua_State* L, const char* name)
{
if (name)
{
lua_pushstring(L,name);
lua_rawget(L,-2);
}
else
lua_pushvalue(L,LUA_GLOBALSINDEX);
}tolua_beginmodule(tolua_S,"CCLabelTTF");会调用if部分代码， lua_pushstring (L,name);把字符串CCLabelTTF压栈，lua_rawget(L,-2);获得__G中字段为CCLabelTTF的表，现在__G["CCLabelTTF"] = {}，栈中1个元素__G["CCLabelTTF"]。再看
tolua_function(tolua_S,"create",tolua_Cocos2d_CCLabelTTF_create00);tolua_function的代码如下：
TOLUA_API void tolua_function (lua_State* L, const char* name, lua_CFunction func)
{
lua_pushstring(L,name);
lua_pushcfunction(L,func);
lua_rawset(L,-3);
}
/* method: create of class CCLabelTTF */
#ifndef TOLUA_DISABLE_tolua_Cocos2d_CCLabelTTF_create03
static int tolua_Cocos2d_CCLabelTTF_create03(lua_State* tolua_S)
{
tolua_Error tolua_err;
if (
!tolua_isusertable(tolua_S,1,"CCLabelTTF",0,&tolua_err) ||
!tolua_isnoobj(tolua_S,2,&tolua_err)
)
goto tolua_lerror;
else
{
{
CCLabelTTF* tolua_ret = (CCLabelTTF*) CCLabelTTF::create();
int nID = (tolua_ret) ? (int)tolua_ret->m_uID : -1;
int* pLuaID = (tolua_ret) ? &tolua_ret->m_nLuaID : NULL;
toluafix_pushusertype_ccobject(tolua_S, nID, pLuaID, (void*)tolua_ret,"CCLabelTTF");
}
}
return 1;
tolua_lerror:
return tolua_Cocos2d_CCLabelTTF_create02(tolua_S);
}
#endif //#ifndef TOLUA_DISABLE
TOLUA_API int tolua_isnoobj (lua_State* L, int lo, tolua_Error* err)
{
if (lua_gettop(L)index = lo;
err->array = 0;
err->type = "[no object]";
return 0;
}
TOLUA_API int tolua_isusertable (lua_State* L, int lo, const char* type, int def, tolua_Error* err)
{
if (def && lua_gettop(L)index = lo;
err->array = 0;
err->type = type;
return 0;
}
static int lua_isusertable (lua_State* L, int lo, const char* type)
{
int r = 0;
if (lo < 0) lo = lua_gettop(L)+lo+1;
lua_pushvalue(L,lo);
lua_rawget(L,LUA_REGISTRYINDEX); /* get registry[t] */
if (lua_isstring(L,-1))
{
r = strcmp(lua_tostring(L,-1),type)==0;
if (!r)
{
/* try const */
lua_pushstring(L,"const ");
lua_insert(L,-2);
lua_concat(L,2);
r = lua_isstring(L,-1) && strcmp(lua_tostring(L,-1),type)==0;
}
}
lua_pop(L, 1);
return r;
}tolua_Cocos2d_CCLabelTTF_create1-》tolua_Cocos2d_CCLabelTTF_create00， tolua_Cocos2d_CCLabelTTF_create00的tolua_lerror:部分就是真正出错处理了，这里不追踪错误处理，继续看下非静态函数setFontName对应的c函数的代码：
/* method: setFontName of class CCLabelTTF */
#ifndef TOLUA_DISABLE_tolua_Cocos2d_CCLabelTTF_setFontName00
static int tolua_Cocos2d_CCLabelTTF_setFontName00(lua_State* tolua_S)
{
#ifndef TOLUA_RELEASE
tolua_Error tolua_err;
if (
!tolua_isusertype(tolua_S,1,"CCLabelTTF",0,&tolua_err) ||
!tolua_isstring(tolua_S,2,0,&tolua_err) ||
!tolua_isnoobj(tolua_S,3,&tolua_err)
)
goto tolua_lerror;
else
#endif
{
CCLabelTTF* self = (CCLabelTTF*) tolua_tousertype(tolua_S,1,0);
const char* fontName = ((const char*) tolua_tostring(tolua_S,2,0));
#ifndef TOLUA_RELEASE
if (!self) tolua_error(tolua_S,"invalid 'self' in function 'setFontName'", NULL);
#endif
{
self->setFontName(fontName);
}
}
return 0;
#ifndef TOLUA_RELEASE
tolua_lerror:
tolua_error(tolua_S,"#ferror in function 'setFontName'.",&tolua_err);
return 0;
#endif
}
#endif //#ifndef TOLUA_DISABLE
TOLUA_API int tolua_isusertype (lua_State* L, int lo, const char* type, int def, tolua_Error* err)
{
if (def && lua_gettop(L)index = lo;
err->array = 0;
err->type = type;
return 0;
}
static int lua_isusertype (lua_State* L, int lo, const char* type)
{
if (!lua_isuserdata(L,lo)) {
if (!push_table_instance(L, lo)) {
return 0;
};
};
{
/* check if it is of the same type */
int r;
const char *tn;
if (lua_getmetatable(L,lo)) /* if metatable? */
{
lua_rawget(L,LUA_REGISTRYINDEX); /* get registry[mt] */
tn = lua_tostring(L,-1);
r = tn && (strcmp(tn,type) == 0);
lua_pop(L, 1);
if (r)
return 1;
else
{
/* check if it is a specialized class */
lua_pushstring(L,"tolua_super");
lua_rawget(L,LUA_REGISTRYINDEX); /* get super */
lua_getmetatable(L,lo);
lua_rawget(L,-2); /* get super[mt] */
if (lua_istable(L,-1))
{
int b;
lua_pushstring(L,type);
lua_rawget(L,-2); /* get super[mt][type] */
b = lua_toboolean(L,-1);
lua_pop(L,3);
if (b)
return 1;
}
}
}
}
return 0;
}上面研究了cocos怎么把tolua++导出的c函数注册为lua中相应的表的函数变量，以及lua调用这些函数，对应的c函数是怎么最终调用cocos的api的。需要区别类的静态函数与非静态有所区别，一个检查是否是表，一个检查是否是userdata.还有重载的函数它们只有一个注册，需要根据参数判断最终调用哪个。
2、tolua++怎么把cocos的api导出为c函数
下面进行下分析，主要就是怎么用tolua++这个工具。这个工具可以在cocos工程下找到，也可以到网上下载,这个地址是tolua++的参考手册：https://www8.cs.umu.se/kurser/TDBD12/VT04/lab/lua/tolua%2B%2B.html ，里面介绍的很详细。cocos的tolua++里面的readme内容如下：
1. Generating the lua<-->C bindings with tolua++
Build scripts for windows (build.bat) and unix (build.sh) are provided
to generate the relevant files after modifying the .pkg files. These
scripts basically run the following command:
tolua++.exe -L basic.lua -o LuaCocos2d.cpp Cocos2d.pkg
This will generate the bindings file and patch it with come cocos2dx
specific modifications.
On POSIX systems you can also just run "make" to build the bindings
if/when you change .pkg files.
2. Writing .pkg files
1) enum keeps the same
2) remove CC_DLL for the class defines, pay attention to multi inherites
3) remove inline keyword for declaration and implementation
4) remove public protect and private
5) remove the decalration of class member variable
6) keep static keyword
7) remove memeber functions that declared as private or protected
$#include "LuaCocos2d.h"
$pfile "matrix.pkg"
$pfile "ccTypes.pkg"
$pfile "CCObject.pkg"
$pfile "CCCommon.pkg"
$pfile "CCGeometry.pkg"
$pfile "CCArray.pkg"
$pfile "CCDictionary.pkg"
$pfile "CCString.pkg"
$pfile "CCPointExtension.pkg"
$pfile "CCEGLViewProtocol.pkg"不过不推荐这种方法，我们可以生成自己的的cpp加到项目中使用，下面是一个例子：
#ifndef luaApi_hpp
#define luaApi_hpp
#include
#include "cocos2D.h"
USING_NS_CC;
enum FontSize{
SMALL = 10,
MEDIUM = 20,
BIG = 30,
};
class Label : public CCLabelTTF{
public:
Label();
virtual ~Label();
static Label* create(const char *label, FontSize size);
void setPosition(const CCPoint &point);
};
#endif /* luaApi_hpp */
$#include "Label.h"
enum FontSize{
SMALL = 10,
MEDIUM = 20,
BIG = 30,
};
class Label : public CCLabelTTF{
Label();
virtual ~Label();
static Label* create(const char *label, FontSize size);
void setPosition(const CCPoint &point);
};
/Users/lewis/Desktop/cocos2dx-2.2.2pak/tools/tolua++/tolua++ -o LuaLabel2.cpp Label.pkg 3、怎么使用cocos提供的接口执行lua文件，实现脚本化或者半脚本化编程
在项目中加入导出的cpp文件，然后向lua虚拟机注册这些c函数，就可以在lua中使用了，查看下面代码：
//新建状态
lua_State *L = luaL_newstate();
luaL_openlibs(L);//we will use lua io api
//向lua注册c函数
lua_register(L, "cAPI_addLabel", cAPI_addLabel);
//加载并执行脚本
string path = CCFileUtils::sharedFileUtils()->fullPathForFilename("luacallc.lua");
luaL_dofile(L, path.c_str());
//关闭状态
lua_close(L);
CCLuaEngine::defaultEngine()->executeScriptFile("luacallc.lua");int CCLuaEngine::executeScriptFile(const char* filename)
{
int ret = m_stack->executeScriptFile(filename);
m_stack->clean();
return ret;
}int CCLuaStack::executeScriptFile(const char* filename)
{
#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)
std::string code("require \"");
code.append(filename);
code.append("\"");
return executeString(code.c_str());
#else
std::string fullPath = CCFileUtils::sharedFileUtils()->fullPathForFilename(filename);
++m_callFromLua;
int nRet = luaL_dofile(m_state, fullPath.c_str());
--m_callFromLua;
CC_ASSERT(m_callFromLua >= 0);
// lua_gc(m_state, LUA_GCCOLLECT, 0);
if (nRet != 0)
{
CCLOG("[LUA ERROR] %s", lua_tostring(m_state, -1));
lua_pop(m_state, 1);
return nRet;
}
return 0;
#endif
}
CCLuaEngine::defaultEngine()->executeString("print('hello world')");
CCScriptEngineManager::sharedManager()->setScriptEngine(CCLuaEngine::defaultEngine());
extern int tolua_Label_open (lua_State* tolua_S);
tolua_Label_open(CCLuaEngine::defaultEngine()->getLuaStack()->getLuaState());
void CCScriptEngineManager::setScriptEngine(CCScriptEngineProtocol *pScriptEngine)
{
removeScriptEngine();
m_pScriptEngine = pScriptEngine;
}void CCScriptEngineManager::removeScriptEngine(void)
{
if (m_pScriptEngine)
{
delete m_pScriptEngine;
m_pScriptEngine = NULL;
}
}
CCLuaEngine* CCLuaEngine::defaultEngine(void)
{
if (!m_defaultEngine)
{
m_defaultEngine = new CCLuaEngine();
m_defaultEngine->init();
}
return m_defaultEngine;
}bool CCLuaEngine::init(void)
{
m_stack = CCLuaStack::create();
m_stack->retain();
return true;
}CCLuaStack *CCLuaStack::create(void)
{
CCLuaStack *stack = new CCLuaStack();
stack->init();
stack->autorelease();
return stack;
}bool CCLuaStack::init(void)
{
m_state = lua_open();
luaL_openlibs(m_state);
tolua_Cocos2d_open(m_state);
toluafix_open(m_state);
// Register our version of the global "print" function
const luaL_reg global_functions [] = {
{"print", lua_print},
{NULL, NULL}
};
luaL_register(m_state, "_G", global_functions);
tolua_CocoStudio_open(m_state);
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS || CC_TARGET_PLATFORM == CC_PLATFORM_MAC)
CCLuaObjcBridge::luaopen_luaoc(m_state);
#endif
register_all_cocos2dx_manual(m_state);
register_all_cocos2dx_extension_manual(m_state);
register_all_cocos2dx_studio_manual(m_state);
// add cocos2dx loader
addLuaLoader(cocos2dx_lua_loader);
return true;
}
int lua_print(lua_State * luastate)
{
int nargs = lua_gettop(luastate);
std::string t;
for (int i=1; i <= nargs; i++)
{
if (lua_istable(luastate, i))
t += "table";
else if (lua_isnone(luastate, i))
t += "none";
else if (lua_isnil(luastate, i))
t += "nil";
else if (lua_isboolean(luastate, i))
{
if (lua_toboolean(luastate, i) != 0)
t += "true";
else
t += "false";
}
else if (lua_isfunction(luastate, i))
t += "function";
else if (lua_islightuserdata(luastate, i))
t += "lightuserdata";
else if (lua_isthread(luastate, i))
t += "thread";
else
{
const char * str = lua_tostring(luastate, i);
if (str)
t += lua_tostring(luastate, i);
else
t += lua_typename(luastate, lua_type(luastate, i));
}
if (i!=nargs)
t += "\t";
}
CCLOG("[LUA-print] %s", t.c_str());
return 0;
}4、cocos在对返回userdata类型的c api的特殊处理
cocos对返回userdata类型的c api做了特殊处理。查看下面代码:
class CC_DLL CCObject : public CCCopying
{
public:
// object id, CCScriptSupport need public m_uID
unsigned int m_uID;
// Lua reference id
int m_nLuaID;CCObject::CCObject(void)
: m_nLuaID(0)
, m_uReference(1) // when the object is created, the reference count of it is 1
, m_uAutoReleaseCount(0)
{
static unsigned int uObjectCount = 0;
m_uID = ++uObjectCount;
}CCObject::~CCObject(void)
{
// if the object is managed, we should remove it
// from pool manager
if (m_uAutoReleaseCount > 0)
{
CCPoolManager::sharedPoolManager()->removeObject(this);
}
// if the object is referenced by Lua engine, remove it
if (m_nLuaID)
{
CCScriptEngineManager::sharedManager()->getScriptEngine()->removeScriptObjectByCCObject(this);
}
else
{
CCScriptEngineProtocol* pEngine = CCScriptEngineManager::sharedManager()->getScriptEngine();
if (pEngine != NULL && pEngine->getScriptType() == kScriptTypeJavascript)
{
pEngine->removeScriptObjectByCCObject(this);
}
}
}
/* method: autorelease of class CCObject */
#ifndef TOLUA_DISABLE_tolua_Cocos2d_CCObject_autorelease00
static int tolua_Cocos2d_CCObject_autorelease00(lua_State* tolua_S)
{
#ifndef TOLUA_RELEASE
tolua_Error tolua_err;
if (
!tolua_isusertype(tolua_S,1,"CCObject",0,&tolua_err) ||
!tolua_isnoobj(tolua_S,2,&tolua_err)
)
goto tolua_lerror;
else
#endif
{
CCObject* self = (CCObject*) tolua_tousertype(tolua_S,1,0);
#ifndef TOLUA_RELEASE
if (!self) tolua_error(tolua_S,"invalid 'self' in function 'autorelease'", NULL);
#endif
{
CCObject* tolua_ret = (CCObject*) self->autorelease();
int nID = (tolua_ret) ? (int)tolua_ret->m_uID : -1;
int* pLuaID = (tolua_ret) ? &tolua_ret->m_nLuaID : NULL;
toluafix_pushusertype_ccobject(tolua_S, nID, pLuaID, (void*)tolua_ret,"CCObject");
}
}
return 1;
#ifndef TOLUA_RELEASE
tolua_lerror:
tolua_error(tolua_S,"#ferror in function 'autorelease'.",&tolua_err);
return 0;
#endif
}
#endif //#ifndef TOLUA_DISABLE上面代码是任选的一个导出的c api,int nID = (tolua_ret) ? (int)tolua_ret->m_uID : -1;表示函数有返回值，也就是函数如果返回userdata给lua,那么nID=m_uID,m_uID这个值是CCObject构造函数时得到的，然后有返回值就会把m_nLuaID的地址给pLuaID，接着调用toluafix_pushusertype_ccobject(tolua_S, nID, pLuaID, (void*)tolua_ret,"CCObject")，代码如下：
TOLUA_API int toluafix_pushusertype_ccobject(lua_State* L,
int refid,
int* p_refid,
void* ptr,
const char* type)
{
if (ptr == NULL || p_refid == NULL)
{
lua_pushnil(L);
return -1;
}
if (*p_refid == 0)
{
*p_refid = refid;
lua_pushstring(L, TOLUA_REFID_PTR_MAPPING);
lua_rawget(L, LUA_REGISTRYINDEX); /* stack: refid_ptr */
lua_pushinteger(L, refid); /* stack: refid_ptr refid */
lua_pushlightuserdata(L, ptr); /* stack: refid_ptr refid ptr */
lua_rawset(L, -3); /* refid_ptr[refid] = ptr, stack: refid_ptr */
lua_pop(L, 1); /* stack: - */
lua_pushstring(L, TOLUA_REFID_TYPE_MAPPING);
lua_rawget(L, LUA_REGISTRYINDEX); /* stack: refid_type */
lua_pushinteger(L, refid); /* stack: refid_type refid */
lua_pushstring(L, type); /* stack: refid_type refid type */
lua_rawset(L, -3); /* refid_type[refid] = type, stack: refid_type */
lua_pop(L, 1); /* stack: - */
//printf("[LUA] push CCObject OK - refid: %d, ptr: %x, type: %s\n", *p_refid, (int)ptr, type);
}
tolua_pushusertype_and_addtoroot(L, ptr, type);
return 0;
}/* get function: y of class CCPoint */
#ifndef TOLUA_DISABLE_tolua_get_CCPoint_y
static int tolua_get_CCPoint_y(lua_State* tolua_S)
{
CCPoint* self = (CCPoint*) tolua_tousertype(tolua_S,1,0);
#ifndef TOLUA_RELEASE
if (!self) tolua_error(tolua_S,"invalid 'self' in accessing variable 'y'",NULL);
#endif
tolua_pushnumber(tolua_S,(lua_Number)self->y);
return 1;
}
#endif //#ifndef TOLUA_DISABLE5、cocos提供的重要的与lua通信的接口
cocos为我们提供了一些接口直接调用脚本，也就是脚本事件。游戏中的每个节点可以添加脚本处理。CCNode这个类型并没有导出onEnter、onExit、
cleanup、onEnterTransitionDidFinish、OnExitTransitionDidStart这几个函数，因为他们不是供客户直接调用的，而是调用时间写死了，onEnter是在节点加入一个真正running的节点，或者加入一个非running父节点然后父节点running了这两种情况下调用的。可以继承CCNode,然后重写onEnter并且调用CCNode的onEnter，不过不推荐，可以重写init函数完成。而在lua脚本中，我们直接用c api对于的lua api创建的节点，要想给它添加节点，添加动作，我们不想直接创建，然后后面接着写添加节点跟动作的代码，因为脚本被执行时，这些代码都会被执行，假如这个节点根本没用的，代码也被执行了。要想避免这种情况可以向cocos注册脚本事件，等到这个节点真正被使用时，才会调用它的onEnter等方法。注册脚本事件代码如下：
void CCNode::registerScriptHandler(int nHandler)
{
unregisterScriptHandler();
m_nScriptHandler = nHandler;
LUALOG("[LUA] Add CCNode event handler: %d", m_nScriptHandler);
}
/* method: registerScriptHandler of class CCNode */
#ifndef TOLUA_DISABLE_tolua_Cocos2d_CCNode_registerScriptHandler00
static int tolua_Cocos2d_CCNode_registerScriptHandler00(lua_State* tolua_S)
{
#ifndef TOLUA_RELEASE
tolua_Error tolua_err;
if (
!tolua_isusertype(tolua_S,1,"CCNode",0,&tolua_err) ||
(tolua_isvaluenil(tolua_S,2,&tolua_err) || !toluafix_isfunction(tolua_S,2,"LUA_FUNCTION",0,&tolua_err)) ||
!tolua_isnoobj(tolua_S,3,&tolua_err)
)
goto tolua_lerror;
else
#endif
{
CCNode* self = (CCNode*) tolua_tousertype(tolua_S,1,0);
LUA_FUNCTION funcID = ( toluafix_ref_function(tolua_S,2,0));
#ifndef TOLUA_RELEASE
if (!self) tolua_error(tolua_S,"invalid 'self' in function 'registerScriptHandler'", NULL);
#endif
{
self->registerScriptHandler(funcID);
}
}
return 0;
#ifndef TOLUA_RELEASE
tolua_lerror:
tolua_error(tolua_S,"#ferror in function 'registerScriptHandler'.",&tolua_err);
return 0;
#endif
}
#endif //#ifndef TOLUA_DISABLE
void CCNode::onEnter()
{
//fix setTouchEnabled not take effect when called the function in onEnter in JSBinding.
m_bRunning = true;
if (m_eScriptType != kScriptTypeNone)
{
CCScriptEngineManager::sharedManager()->getScriptEngine()->executeNodeEvent(this, kCCNodeOnEnter);
}
//Judge the running state for prevent called onEnter method more than once,it's possible that this function called by addChild
if (m_pChildren && m_pChildren->count() > 0)
{
CCObject* child;
CCNode* node;
CCARRAY_FOREACH(m_pChildren, child)
{
node = (CCNode*)child;
if (!node->isRunning())
{
node->onEnter();
}
}
}
this->resumeSchedulerAndActions();
}
int CCLuaEngine::executeNodeEvent(CCNode* pNode, int nAction)
{
int nHandler = pNode->getScriptHandler();
if (!nHandler) return 0;
switch (nAction)
{
case kCCNodeOnEnter:
m_stack->pushString("enter");
break;
case kCCNodeOnExit:
m_stack->pushString("exit");
break;
case kCCNodeOnEnterTransitionDidFinish:
m_stack->pushString("enterTransitionFinish");
break;
case kCCNodeOnExitTransitionDidStart:
m_stack->pushString("exitTransitionStart");
break;
case kCCNodeOnCleanup:
m_stack->pushString("cleanup");
break;
default:
return 0;
}
int ret = m_stack->executeFunctionByHandler(nHandler, 1);
m_stack->clean();
return ret;
}
function eventHandle(event)
if event = "enter" then
-- call enter handler
elseif event = "exit" then
-- call exit handler
elseif event = "enterTransitionFinish" then
-- call enterTransitionFinish handler
elseif event = "exitTransitionStart" then
-- call exitTransitionStart handler
elseif event = "cleanup" then
-- call cleanup handler
end
endvoid CCNode::scheduleUpdateWithPriorityLua(int nHandler, int priority)
{
unscheduleUpdate();
m_nUpdateScriptHandler = nHandler;
m_pScheduler->scheduleUpdateForTarget(this, priority, !m_bRunning);
}// Draw the Scene
void CCDirector::drawScene(void)
{
// calculate "global" dt
calculateDeltaTime();
//tick before glClear: issue #533
if (! m_bPaused)
{
m_pScheduler->update(m_fDeltaTime);
}// main loop
void CCScheduler::update(float dt)
{
m_bUpdateHashLocked = true;
if (m_fTimeScale != 1.0f)
{
dt *= m_fTimeScale;
}
// Iterate over all the Updates' selectors
tListEntry *pEntry, *pTmp;
// updates with priority < 0
DL_FOREACH_SAFE(m_pUpdatesNegList, pEntry, pTmp)
{
if ((! pEntry->paused) && (! pEntry->markedForDeletion))
{
pEntry->target->update(dt);
}
}
// updates with priority == 0
DL_FOREACH_SAFE(m_pUpdates0List, pEntry, pTmp)
{
if ((! pEntry->paused) && (! pEntry->markedForDeletion))
{
pEntry->target->update(dt);
}
}
// updates with priority > 0
DL_FOREACH_SAFE(m_pUpdatesPosList, pEntry, pTmp)
{
if ((! pEntry->paused) && (! pEntry->markedForDeletion))
{
pEntry->target->update(dt);
}
}
// override me
void CCNode::update(float fDelta)
{
if (m_nUpdateScriptHandler)
{
CCScriptEngineManager::sharedManager()->getScriptEngine()->executeSchedule(m_nUpdateScriptHandler, fDelta, this);
}
if (m_pComponentContainer && !m_pComponentContainer->isEmpty())
{
m_pComponentContainer->visit(fDelta);
}
}OK差不多了。本文研究了c/c++与lua的相互调用，cocos如何使用tolua++导出c api供lua使用,如何使用cocos进行lua脚本编程，cocos的CCNode提供了哪些重要的调用lua脚本的接口
本文有的地方没有深入，需要进一步研究lua的c api、辅助库、以及lua functions, 进一步研究tolua++怎么包装lua的，然后再更深入挖掘cocos的lua的使用，比如cocos怎么定制tolua++的，相关的toluafix前缀的函数具体干了什么可以仔细研究下。还有lua与oc的桥接，lua与java的桥接可以研究等等。有些代码看了部分知道了做了什么，但是不代表知道具体的设计思想。读代码读的更是一种思想，可以启发写出好代码。