来自看雪：Cocos2dlua手游 Lua解密与资源解密实战
https://mp.weixin.qq.com/s/WeYxlXZvCPv_3nGgeKdunw
Cocos2dlua 逆向相关学习，略有删减，直接进入正文
APK大致如下：
. ├── assets │ ├── res │ │ ├── ani │ │ │ └── logo │ │ │ └── logo.png │ ├── src │ │ ├── main.lua │ │ └── main.lua64 ├── lib │ ├── arm64-v8a │ │ ├── libBugly.so │ │ └── libcocos2dlua.so │ └── armeabi-v7a │ ├── libBugly.so │ └── libcocos2dlua.so └── stamp-cert-sha256
其中.lua64为标准LuaJit文件，而.lua的文件头有点奇怪。
.lua文件头：abcd，再看资源文件.png，发现也是加密的：
综上，我们需要实现的目标：1、解密.lua文件；2、解密.png文件。
这个不多介绍了窝，在理论篇中已经提到了。对于此样本的LuaJit的版本是2.1.0-Beta2，并且没有魔改Opcode。
Lua文件加载流程：想要解密.lua文件，了解coco2d-x加载Lua的流程必不可少。
Cocos2d-x环境搭建：参考官方Docs，搭建所需环境：
由于Android的应用层是从Activity开始的，也就是创建完一个Cocos2dx后src文件夹下的Java文件，其中主要看Activity创建时的操作。
package org.cocos2dx.lua;
import android.os.Bundle;
import org.cocos2dx.lib.Cocos2dxActivity;
public class AppActivity extends Cocos2dxActivity{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.setEnableVirtualButton(false);
super.onCreate(savedInstanceState);
// Workaround in https://stackoverflow.com/questions/16283079/re-launch-of-activity-on-home-button-but-only-the-first-time/16447508
if (!isTaskRoot()) {
// Android launched another instance of the root activity into an existing task
// so just quietly finish and go away, dropping the user back into the activity
// at the top of the stack (ie: the last state of this task)
// Don't need to finish it again since it's finished in super.onCreate .
return;
}
// DO OTHER INITIALIZATION BELOW
}
}
这个方法很简单，就只调用了父类Cocos2dxActivity的onCreate方法：
@Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Workaround in https://stackoverflow.com/questions/16283079/re-launch-of-activity-on-home-button-but-only-the-first-time/16447508
if (!isTaskRoot()) {
// Android launched another instance of the root activity into an existing task
// so just quietly finish and go away, dropping the user back into the activity
// at the top of the stack (ie: the last state of this task)
finish();
Log.w(TAG, "[Workaround] Ignore the activity started from icon!");
return;
}
this.hideVirtualButton();
onl oadNativeLibraries();
sContext = this;
this.mHandler = new Cocos2dxHandler(this);
Cocos2dxHelper.init(this);
this.mGLContextAttrs = getGLContextAttrs();
this.init();
if (mVideoHelper == null) {
mVideoHelper = new Cocos2dxVideoHelper(this, mFrameLayout);
}
if(mWebViewHelper == null){
mWebViewHelper = new Cocos2dxWebViewHelper(mFrameLayout);
}
if(mEditBoxHelper == null){
mEditBoxHelper = new Cocos2dxEditBoxHelper(mFrameLayout);
}
Window window = this.getWindow();
window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
// Audio configuration
this.setVolumeControlStream(AudioManager.STREAM_MUSIC);
}
在这个方法中主要看Cocos2dxActivity的初始化方法init，Cocos2dxHandler是工具辅助类，不是重点。
public Cocos2dxGLSurfaceView onCreateView() {
Cocos2dxGLSurfaceView glSurfaceView = new Cocos2dxGLSurfaceView(this);
//this line is need on some device if we specify an alpha bits
// FIXME: is it needed? And it will cause afterimage.
// if(this.mGLContextAttrs[3] > 0) glSurfaceView.getHolder().setFormat(PixelFormat.TRANSLUCENT);
// use custom EGLConfigureChooser
Cocos2dxEGLConfigChooser chooser = new Cocos2dxEGLConfigChooser(this.mGLContextAttrs);
glSurfaceView.setEGLConfigChooser(chooser);
return glSurfaceView;
}
// ......
public void init() {
// FrameLayout 初始化窗口布局
ViewGroup.LayoutParams framelayout_params =
new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT);
mFrameLayout = new ResizeLayout(this);
mFrameLayout.setLayoutParams(framelayout_params);
// Cocos2dxEditText layout 初始化Cocos2dx的文本编辑布局
ViewGroup.LayoutParams edittext_layout_params =
new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
Cocos2dxEditBox edittext = new Cocos2dxEditBox(this);
edittext.setLayoutParams(edittext_layout_params);
mFrameLayout.addView(edittext);
// Cocos2dxGLSurfaceView 初始化Cocos2dx视图
this.mGLSurfaceView = this.onCreateView();
// ...add to FrameLayout 将Cocos2dxGLSurfaceView加入到当前的窗口布局中
mFrameLayout.addView(this.mGLSurfaceView);
// Switch to supported OpenGL (ARGB888) mode on emulator
// this line dows not needed on new emulators and also it breaks stencil buffer
//if (isAndroidEmulator()) // 在模拟器中切换支持OpenGL模式的渲染(ARGB888)
// this.mGLSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
// 设置Cocos2dx的渲染器
this.mGLSurfaceView.setCocos2dxRenderer(new Cocos2dxRenderer());
//设置Cocos2dx的文本编辑
this.mGLSurfaceView.setCocos2dxEditText(edittext);
// Set framelayout as the content view
// 把显示布局（即Cocos2dx的视图）绑定到Activity上，建立显示窗口
setContentView(mFrameLayout);
}
首先在init中先看this.mGLSurfaceView = this.onCreateView();this.mGLSurfaceView是一个Cocos2dxGLSurfaceView类。 进入到Cocos2dxGLSurfaceView这个类，可以看到时继承于GLSurfaceView（可以把GLSurfaceView看成一个视图，里面有个方法设置了这个视图的渲染器，然后通过这个渲染器来进行画面的渲染）。
在Android中，GLSurfaceView是一个支持OpenGL的渲染视图，通过继承SurfaceView中的surface来渲染OpenGL。
并提供了以下特性（来源于网上）：
- 管理一个surface，这个surface就是一块特殊的内存，能直接排版到android的视图view上
- 管理一个EGL display，它能让opengl把内容渲染到上述的surface上
- 用户自定义渲染器(render)
- 让渲染器在独立的线程里运作，和UI线程分离
- 支持按需渲染(on-demand)和连续渲染(continuous)
- 一些可选工具，如调试
重点是自定义的渲染器，也就是Cocos2dx引擎封装的渲染器。 进入Cocos2dxRenderer类，看到他是继承GLSurfaceView.Renderer接口，这个接口定义了三个方法：
- onSurfaceCreated: 创建GLSurfaceView时被调用，只调用一次，做初始化工作
- onSurfaceChanged: 当GLSurfaceView的几何体被改变时被调用
- onDrawFrame: 绘制渲染GLSurfaceView
onSurfaceCreated：
@Override
public void onSurfaceCreated(final GL10 GL10, final EGLConfig EGLConfig) {
Cocos2dxRenderer.nativeInit(this.mScreenWidth, this.mScreenHeight);
this.mLastTickInNanoSeconds = System.nanoTime();
mNativeInitCompleted = true;
}
nativeInit是一个Native函数：
private static native void nativeInit(final int width, final int height);
具体实现在frameworks\cocos2d-x\cocos\platform\android\javaactivity-android.cpp中：
JNIEXPORT void Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeInit(JNIEnv* env, jobject thiz, jint w, jint h)
{
auto director = cocos2d::Director::getInstance();
auto glview = director->getOpenGLView();
if (!glview)
{
glview = cocos2d::GLViewImpl::create("Android app");
glview->setFrameSize(w, h);
director->setOpenGLView(glview);
cocos2d::Application::getInstance()->run();
}
else
{
cocos2d::Director::getInstance()->resetMatrixStack();
cocos2d::EventCustom recreatedEvent(EVENT_RENDERER_RECREATED);
director->getEventDispatcher()->dispatchEvent(&recreatedEvent);
director->setGLDefaultValues();
cocos2d::VolatileTextureMgr::reloadAllTextures();
}
cocos2d::network::_preloadJavaDownloaderClass();
}
重点是cocos2d::Application::getInstance()->run()。
int Application::run()
{
// Initialize instance and cocos2d.
if (! applicationDidFinishLaunching())
{
return 0;
}
return -1;
}
applicationDidFinishLaunching，没错这就是游戏逻辑的入口了：
bool AppDelegate::applicationDidFinishLaunching()
{
// set default FPS
Director::getInstance()->setAnimationInterval(1.0 / 60.0f);
// register lua module
// 初始化 LuaEngine, 在 getInstance 中会初始化 LuaStack, LuaStack 初始化 Lua 环境相关
auto engine = LuaEngine::getInstance();
// 将 LuaEngine 添加到脚本引擎管理器 ScriptEngineManager 中
ScriptEngineManager::getInstance()->setScriptEngine(engine);
// 获取 Lua 环境
lua_State* L = engine->getLuaStack()->getLuaState();
// 注册额外的 C++ API 相关，比如 cocosstudio, spine, audio 相关
lua_module_register(L);
// 设置 cocos 自带的加密相关
register_all_packages();
// 在 LuaStack::executeScriptFile 执行脚本文件时，会通过 LuaStack::luaLoadBuffer 对文件进行解密
LuaStack* stack = engine->getLuaStack();
stack->setXXTEAKeyAndSign("2dxLua", strlen("2dxLua"), "XXTEA", strlen("XXTEA"));
//register custom function
//LuaStack* stack = engine->getLuaStack();
//register_custom_function(stack->getLuaState());
#if CC_64BITS
FileUtils::getInstance()->addSearchPath("src/64bit");
#endif
FileUtils::getInstance()->addSearchPath("src");
FileUtils::getInstance()->addSearchPath("res");
if (engine->executeScriptFile("main.lua"))
{
return false;
}
return true;
}
LuaEngine::getInstance();这段代码实例化了LuaEngine。 下面分析LuaEngine初始化过程：
LuaEngine* LuaEngine::getInstance(void)
{
if (!_defaultEngine)
{
_defaultEngine = new (std::nothrow) LuaEngine();
_defaultEngine->init();
}
return _defaultEngine;
}
接下来是_defaultEngine->init()：
bool LuaEngine::init(void)
{
_stack = LuaStack::create();
_stack->retain();
return true;
}
继续进入：
LuaStack *LuaStack::create()
{
LuaStack *stack = new (std::nothrow) LuaStack();
stack->init();
stack->autorelease();
return stack;
}
下面是stack->init()：
bool LuaStack::init()
{
// 初始化Lua环境并打开标准库
_state = lua_open();
luaL_openlibs(_state);
toluafix_open(_state);
// Register our version of the global "print" function
// 注册全局函数print到lua中，它会覆盖lua库中的print方法
const luaL_Reg global_functions [] = {
{"print", lua_print},
{"release_print",lua_release_print},
{nullptr, nullptr}
};
// 注册全局变量
luaL_register(_state, "_G", global_functions);
// 注册cocos2d-x引擎的API到lua环境中
g_luaType.clear();
register_all_cocos2dx(_state);
register_all_cocos2dx_backend(_state);
register_all_cocos2dx_manual(_state);
register_all_cocos2dx_module_manual(_state);
register_all_cocos2dx_math_manual(_state);
register_all_cocos2dx_shaders_manual(_state);
register_all_cocos2dx_bytearray_manual(_state);
tolua_luanode_open(_state);
register_luanode_manual(_state);
#if CC_USE_PHYSICS
// 导入使用的physics相关API
register_all_cocos2dx_physics(_state);
register_all_cocos2dx_physics_manual(_state);
#endif
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS || CC_TARGET_PLATFORM == CC_PLATFORM_MAC)
// 导入ios下调用object-c相关API
LuaObjcBridge::luaopen_luaoc(_state);
#endif
#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)
// 导入android下调用java相关API
LuaJavaBridge::luaopen_luaj(_state);
#endif
register_all_cocos2dx_deprecated(_state);
register_all_cocos2dx_manual_deprecated(_state);
tolua_script_handler_mgr_open(_state);
// add cocos2dx loader
// 添加Lua的加载器,该方法将cocos2dx_lua_loader方法添加到Lua全局变量package下的loaders成员中
// 当requires加载脚本时，Lua会使用package下的loaders中的加载器，即cocos2dx_lua_loader来加载
// 设定cocos2dx_lua_loader，可以使得我们自定义设置搜索路径相关，且拓展实现对脚本的加密解密相关
addLuaLoader(cocos2dx_lua_loader);
return true;
}
重点在cocos2dx_lua_loader方法(这个方法在frameworks\cocos2d-x\cocos\scripting\lua-bindings\manual\Cocos2dxLuaLoader.cpp)：
int cocos2dx_lua_loader(lua_State *L)
{
// 后缀为luac和lua
static const std::string BYTECODE_FILE_EXT = ".luac";
static const std::string NOT_BYTECODE_FILE_EXT = ".lua";
// require传入的要加载的文件名，例如：require("a.b") 查找文件为：a/b.lua
std::string filename(luaL_checkstring(L, 1));
size_t pos = filename.rfind(BYTECODE_FILE_EXT);
// 去掉后缀名".luac"或“.lua”
if (pos != std::string::npos && pos == filename.length() - BYTECODE_FILE_EXT.length())
filename = filename.substr(0, pos);
else
{
pos = filename.rfind(NOT_BYTECODE_FILE_EXT);
if (pos != std::string::npos && pos == filename.length() - NOT_BYTECODE_FILE_EXT.length())
filename = filename.substr(0, pos);
}
// 将 "." 替换为 "/"
pos = filename.find_first_of('.');
while (pos != std::string::npos)
{
filename.replace(pos, 1, "/");
pos = filename.find_first_of('.');
}
// search file in package.path
Data chunk;
std::string chunkName;
FileUtils* utils = FileUtils::getInstance();
// 获取 package.path 的变量
lua_getglobal(L, "package");
lua_getfield(L, -1, "path");
// 通过 package.path 获取搜索路径相关，该路径为模版路径，格式类似于：
// ?; ?.lua; c:\Users\?; /usr/local/lua/lua/?/?.lua 以“;”作为分割符
std::string searchpath(lua_tostring(L, -1));
lua_pop(L, 1);
size_t begin = 0;
size_t next = searchpath.find_first_of(';', 0);
// 遍历 package.path 中的所有路径，查找文件是否存在，若文件存在则通过 getDataFromFile 读取文件数据
do
{
if (next == std::string::npos)
next = searchpath.length();
std::string prefix = searchpath.substr(begin, next-begin);
if (prefix[0] == '.' && prefix[1] == '/')
prefix = prefix.substr(2);
pos = prefix.rfind(BYTECODE_FILE_EXT);
if (pos != std::string::npos && pos == prefix.length() - BYTECODE_FILE_EXT.length())
{
prefix = prefix.substr(0, pos);
}
else
{
pos = prefix.rfind(NOT_BYTECODE_FILE_EXT);
if (pos != std::string::npos && pos == prefix.length() - NOT_BYTECODE_FILE_EXT.length())
prefix = prefix.substr(0, pos);
}
pos = prefix.find_first_of('?', 0);
while (pos != std::string::npos)
{
prefix.replace(pos, 1, filename);
pos = prefix.find_first_of('?', pos + filename.length() + 1);
}
chunkName = prefix + BYTECODE_FILE_EXT;
if (utils->isFileExist(chunkName)) // && !utils->isDirectoryExist(chunkName))
{
chunk = utils->getDataFromFile(chunkName);
break;
}
else
{
chunkName = prefix + NOT_BYTECODE_FILE_EXT;
if (utils->isFileExist(chunkName) ) //&& !utils->isDirectoryExist(chunkName))
{
chunk = utils->getDataFromFile(chunkName);
break;
}
else
{
chunkName = prefix;
if (utils->isFileExist(chunkName)) // && !utils->isDirectoryExist(chunkName))
{
chunk = utils->getDataFromFile(chunkName);
break;
}
}
}
// 指定搜素路径下不存在该文件, 下一个
begin = next + 1;
next = searchpath.find_first_of(';', begin);
} while (begin < searchpath.length());
// 判断文件内容是否获取成功
if (chunk.getSize() > 0)
{
// 加载文件
LuaStack* stack = LuaEngine::getInstance()->getLuaStack();
stack->luaLoadBuffer(L, reinterpret_cast<const char*>(chunk.getBytes()),
static_cast<int>(chunk.getSize()), chunkName.c_str());
}
else
{
CCLOG("can not get file data of %s", chunkName.c_str());
return 0;
}
return 1;
}
通过此处的代码，可以了解到cocos2d-x是如何搜索指定的lua文件。 同时也会明白require为何可以使用 "." 来设定文件路径了，比如：
require "cocos.cocos2d.Cocos2d" require "cocos.cocos2d.Cocos2dConstants" require "cocos.cocos2d.functions"
再来看下stack->luaLoadBuffer的实现：
int LuaStack::luaLoadBuffer(lua_State *L, const char *chunk, int chunkSize, const char *chunkName)
{
int r = 0;
// 判断是否加密，若lua脚本加密，则解密后在加载脚本文件
// luaL_loadbuffer 用于加载并编译Lua代码，并将其压入栈中
if (_xxteaEnabled && strncmp(chunk, _xxteaSign, _xxteaSignLen) == 0)
{
// decrypt XXTEA
xxtea_long len = 0;
unsigned char* result = xxtea_decrypt((unsigned char*)chunk + _xxteaSignLen,
(xxtea_long)chunkSize - _xxteaSignLen,
(unsigned char*)_xxteaKey,
(xxtea_long)_xxteaKeyLen,
&len);
unsigned char* content = result;
xxtea_long contentSize = len;
skipBOM((const char*&)content, (int&)contentSize);
r = luaL_loadbuffer(L, (char*)content, contentSize, chunkName);
free(result);
}
else
{
skipBOM(chunk, chunkSize);
r = luaL_loadbuffer(L, chunk, chunkSize, chunkName);
}
// 判定内容是否存在错误
#if defined(COCOS2D_DEBUG) && COCOS2D_DEBUG > 0
if (r)
{
switch (r)
{
case LUA_ERRSYNTAX:
// 语法错误
CCLOG("[LUA ERROR] load \"%s\", error: syntax error during pre-compilation.", chunkName);
break;
case LUA_ERRMEM:
// 内存分配错误
CCLOG("[LUA ERROR] load \"%s\", error: memory allocation error.", chunkName);
break;
case LUA_ERRFILE:
// 文件错误
CCLOG("[LUA ERROR] load \"%s\", error: cannot open/read file.", chunkName);
break;
default:
// 未知错误
CCLOG("[LUA ERROR] load \"%s\", error: unknown.", chunkName);
}
}
#endif
return r;
}
至此，Lua文件的加载流程结束。 下面是Lua文件主要加载流程图
了解了Coco2d-x Lua文件基本的加载流程，可以帮助我们很快的定位关键方法。
快速定位：由于所有的Lua文件加载必定经过cocos2d::LuaStack::luaLoadBuffer，所以可以直接定位，进行回溯。
定位至cocos2dx_lua_loader：
在luaLoadBuffer前调用了decodeLuaData，怀疑这就是解密Lua的关键方法。
下面是伪代码：
_BYTE *__fastcall decodeLuaData(cocos2d::Data *a1, int *size)
{
_BYTE *v3; // r0
_BYTE *v4; // r5
int v6; // r0
int v7; // r2
int v8; // r3
bool v9; // cc
unsigned int v10; // r1
_BYTE *v11; // r12
_BYTE *v12; // r0
char v13; // t1
_BYTE *v14; // r0
char v15[4]; // [sp+0h] [bp-18h]
v3 = (_BYTE *)cocos2d::Data::getBytes(a1);
v4 = v3;
if ( *size > 8 && *v3 == 'a' && v3[1] == 'b' && v3[2] == 'c' && v3[3] == 'd' )
{
v6 = _hexToDecimal(v3 + 4, 4);
v7 = *size;
v8 = 0;
v9 = *size <= 8;
v15[3] = v6;
v15[2] = (unsigned __int16)(v6 - 2048) >> 8;
v10 = (unsigned int)(v6 - 2048) >> 24;
v15[1] = (unsigned int)(v6 - 2048) >> 16;
v15[0] = (unsigned int)(v6 - 2048) >> 24;
if ( !v9 )
{
v11 = v4 - 1;
v12 = v4 + 7;
while ( 1 )
{
v13 = *++v12;
++v8;
*++v11 = v13 ^ v10;
v7 = *size;
if ( *size <= v8 + 8 )
break;
LOBYTE(v10) = v15[v8 & 3];
}
}
v14 = &v4[v7 - 8];
*v14 = 0;
v14[1] = 0;
v14[2] = 0;
v14[3] = 0;
v14[4] = 0;
v14[5] = 0;
v14[6] = 0;
v14[7] = 0;
*size -= 8;
}
return v4;
}
此方法首先获取文件数据，而后判断文件头，文件头正是abcd。 可以肯定这就是解密.lua的算法。如果不确定，我们可以使用Frida进行Hook验证猜想，我这里就不Hook了。
算法还原：要实现算法的还原，我们就要依据伪代码或是汇编代码翻译成可用代码，可以发现IDA所反汇编的伪代码中包含了一些特定的宏，例如：LOBYTE
要了解这些宏的用途，我们可以参考ida_root/plugins/def.h
我这里使用了Python：
import struct
from loguru import logger
def _hexToDecimal(data, offset):
if offset <= 0:
return 0
return struct.unpack(">I", data[:offset])[0]
def LOBYTE(d):
return d & 0xff
def decodeLuaData(data, size):
v4 = bytearray(data)
v15 = [0] * 4
if size > 8 and data[0] == ord('a') and data[1] == ord('b') and data[2] == ord('c') and data[3] == ord('d'):
logger.info("find special exts")
v6 = _hexToDecimal(data[4:], 4)
v15[3] = v6
v15[2] = (v6 - 2048) >> 8
v10 = (v6 - 2048) >> 24
v15[1] = (v6 - 2048) >> 16
v15[0] = (v6 - 2048) >> 24
if size > 8:
i = 0
while 1:
v13 = v4[8 + i]
v4[i] = v13 ^ v10
i += 1
if size <= i + 8:
break
v10 = LOBYTE(v15[i & 3])
size -= 8
return v4[:-8]
解密后，发现还是LuaJit，那么直接类同.lua64反汇编即可。
回到Lua文件加载流程分析时提到的LuaStack::init()方法中，调用了：register_all_cocos2dx
TOLUA_API int register_all_cocos2dx(lua_State* tolua_S)
{
tolua_open(tolua_S);
tolua_module(tolua_S,"cc",0);
tolua_beginmodule(tolua_S,"cc");
lua_register_cocos2dx_Ref(tolua_S);
lua_register_cocos2dx_Material(tolua_S);
lua_register_cocos2dx_Console(tolua_S);
lua_register_cocos2dx_Node(tolua_S);
lua_register_cocos2dx_Scene(tolua_S);
lua_register_cocos2dx_TransitionScene(tolua_S);
lua_register_cocos2dx_TransitionEaseScene(tolua_S);
lua_register_cocos2dx_TransitionMoveInL(tolua_S);
lua_register_cocos2dx_TransitionMoveInB(tolua_S);
lua_register_cocos2dx_AtlasNode(tolua_S);
lua_register_cocos2dx_TileMapAtlas(tolua_S);
lua_register_cocos2dx_TransitionMoveInT(tolua_S);
lua_register_cocos2dx_TMXTilesetInfo(tolua_S);
lua_register_cocos2dx_TransitionMoveInR(tolua_S);
lua_register_cocos2dx_Action(tolua_S);
lua_register_cocos2dx_FiniteTimeAction(tolua_S);
lua_register_cocos2dx_ActionInstant(tolua_S);
lua_register_cocos2dx_Hide(tolua_S);
lua_register_cocos2dx_ParticleSystem(tolua_S);
lua_register_cocos2dx_ParticleSystemQuad(tolua_S);
lua_register_cocos2dx_ParticleSpiral(tolua_S);
lua_register_cocos2dx_GridBase(tolua_S);
lua_register_cocos2dx_AnimationCache(tolua_S);
lua_register_cocos2dx_ActionInterval(tolua_S);
lua_register_cocos2dx_ActionCamera(tolua_S);
lua_register_cocos2dx_ProgressFromTo(tolua_S);
lua_register_cocos2dx_MoveBy(tolua_S);
lua_register_cocos2dx_MoveTo(tolua_S);
lua_register_cocos2dx_JumpBy(tolua_S);
lua_register_cocos2dx_EventListener(tolua_S);
lua_register_cocos2dx_EventListenerKeyboard(tolua_S);
lua_register_cocos2dx_EventListenerMouse(tolua_S);
lua_register_cocos2dx_TransitionRotoZoom(tolua_S);
lua_register_cocos2dx_Event(tolua_S);
lua_register_cocos2dx_EventController(tolua_S);
lua_register_cocos2dx_Director(tolua_S);
lua_register_cocos2dx_Scheduler(tolua_S);
lua_register_cocos2dx_ActionEase(tolua_S);
lua_register_cocos2dx_EaseElastic(tolua_S);
lua_register_cocos2dx_EaseElasticOut(tolua_S);
lua_register_cocos2dx_EaseQuadraticActionInOut(tolua_S);
lua_register_cocos2dx_EaseBackOut(tolua_S);
lua_register_cocos2dx_Texture2D(tolua_S);
lua_register_cocos2dx_TransitionSceneOriented(tolua_S);
lua_register_cocos2dx_TransitionFlipX(tolua_S);
lua_register_cocos2dx_CameraBackgroundBrush(tolua_S);
lua_register_cocos2dx_CameraBackgroundDepthBrush(tolua_S);
lua_register_cocos2dx_CameraBackgroundColorBrush(tolua_S);
lua_register_cocos2dx_GridAction(tolua_S);
lua_register_cocos2dx_TiledGrid3DAction(tolua_S);
lua_register_cocos2dx_FadeOutTRTiles(tolua_S);
lua_register_cocos2dx_FadeOutUpTiles(tolua_S);
lua_register_cocos2dx_FadeOutDownTiles(tolua_S);
lua_register_cocos2dx_StopGrid(tolua_S);
lua_register_cocos2dx_Technique(tolua_S);
lua_register_cocos2dx_SkewTo(tolua_S);
lua_register_cocos2dx_SkewBy(tolua_S);
lua_register_cocos2dx_EaseQuadraticActionOut(tolua_S);
lua_register_cocos2dx_TransitionProgress(tolua_S);
lua_register_cocos2dx_TransitionProgressVertical(tolua_S);
lua_register_cocos2dx_Layer(tolua_S);
lua_register_cocos2dx_TMXTiledMap(tolua_S);
lua_register_cocos2dx_Grid3DAction(tolua_S);
lua_register_cocos2dx_BaseLight(tolua_S);
lua_register_cocos2dx_SpotLight(tolua_S);
lua_register_cocos2dx_FadeTo(tolua_S);
lua_register_cocos2dx_FadeIn(tolua_S);
lua_register_cocos2dx_DirectionLight(tolua_S);
lua_register_cocos2dx_EventListenerCustom(tolua_S);
lua_register_cocos2dx_FlipX3D(tolua_S);
lua_register_cocos2dx_FlipY3D(tolua_S);
lua_register_cocos2dx_EaseSineInOut(tolua_S);
lua_register_cocos2dx_TransitionFlipAngular(tolua_S);
lua_register_cocos2dx_EaseElasticInOut(tolua_S);
lua_register_cocos2dx_EaseBounce(tolua_S);
lua_register_cocos2dx_Show(tolua_S);
lua_register_cocos2dx_FadeOut(tolua_S);
lua_register_cocos2dx_CallFunc(tolua_S);
lua_register_cocos2dx_EventMouse(tolua_S);
lua_register_cocos2dx_GLView(tolua_S);
lua_register_cocos2dx_EaseBezierAction(tolua_S);
lua_register_cocos2dx_ParticleFireworks(tolua_S);
lua_register_cocos2dx_MenuItem(tolua_S);
lua_register_cocos2dx_MenuItemSprite(tolua_S);
lua_register_cocos2dx_MenuItemImage(tolua_S);
lua_register_cocos2dx_AutoPolygon(tolua_S);
lua_register_cocos2dx_ParticleSmoke(tolua_S);
lua_register_cocos2dx_TransitionZoomFlipAngular(tolua_S);
lua_register_cocos2dx_EaseRateAction(tolua_S);
lua_register_cocos2dx_EaseIn(tolua_S);
lua_register_cocos2dx_EaseExponentialInOut(tolua_S);
lua_register_cocos2dx_CardinalSplineTo(tolua_S);
lua_register_cocos2dx_CatmullRomTo(tolua_S);
lua_register_cocos2dx_Waves3D(tolua_S);
lua_register_cocos2dx_EaseExponentialOut(tolua_S);
lua_register_cocos2dx_Label(tolua_S);
lua_register_cocos2dx_Application(tolua_S);
lua_register_cocos2dx_DelayTime(tolua_S);
lua_register_cocos2dx_LabelAtlas(tolua_S);
lua_register_cocos2dx_EaseCircleActionOut(tolua_S);
lua_register_cocos2dx_SpriteBatchNode(tolua_S);
lua_register_cocos2dx_TMXLayer(tolua_S);
lua_register_cocos2dx_AsyncTaskPool(tolua_S);
lua_register_cocos2dx_ParticleSnow(tolua_S);
lua_register_cocos2dx_EaseElasticIn(tolua_S);
lua_register_cocos2dx_EaseCircleActionInOut(tolua_S);
lua_register_cocos2dx_TransitionFadeTR(tolua_S);
lua_register_cocos2dx_EaseQuarticActionOut(tolua_S);
lua_register_cocos2dx_EventAcceleration(tolua_S);
lua_register_cocos2dx_EaseCubicActionIn(tolua_S);
lua_register_cocos2dx_TextureCache(tolua_S);
lua_register_cocos2dx_ActionTween(tolua_S);
lua_register_cocos2dx_TransitionFadeDown(tolua_S);
lua_register_cocos2dx_ParticleSun(tolua_S);
lua_register_cocos2dx_TransitionProgressHorizontal(tolua_S);
lua_register_cocos2dx_ParticleFire(tolua_S);
lua_register_cocos2dx_FlipX(tolua_S);
lua_register_cocos2dx_FlipY(tolua_S);
lua_register_cocos2dx_EventKeyboard(tolua_S);
lua_register_cocos2dx_TransitionSplitCols(tolua_S);
lua_register_cocos2dx_Timer(tolua_S);
lua_register_cocos2dx_RepeatForever(tolua_S);
lua_register_cocos2dx_Place(tolua_S);
lua_register_cocos2dx_EventListenerAcceleration(tolua_S);
lua_register_cocos2dx_TiledGrid3D(tolua_S);
lua_register_cocos2dx_EaseBounceOut(tolua_S);
lua_register_cocos2dx_RenderTexture(tolua_S);
lua_register_cocos2dx_TintBy(tolua_S);
lua_register_cocos2dx_TransitionShrinkGrow(tolua_S);
lua_register_cocos2dx_ClippingNode(tolua_S);
lua_register_cocos2dx_ActionFloat(tolua_S);
lua_register_cocos2dx_ParticleFlower(tolua_S);
lua_register_cocos2dx_EaseCircleActionIn(tolua_S);
lua_register_cocos2dx_Image(tolua_S); // 加载图片资源
lua_register_cocos2dx_LayerMultiplex(tolua_S);
lua_register_cocos2dx_Blink(tolua_S);
lua_register_cocos2dx_ShaderCache(tolua_S);
lua_register_cocos2dx_JumpTo(tolua_S);
lua_register_cocos2dx_ParticleExplosion(tolua_S);
lua_register_cocos2dx_TransitionJumpZoom(tolua_S);
lua_register_cocos2dx_Pass(tolua_S);
lua_register_cocos2dx_Touch(tolua_S);
lua_register_cocos2dx_CardinalSplineBy(tolua_S);
lua_register_cocos2dx_CatmullRomBy(tolua_S);
lua_register_cocos2dx_NodeGrid(tolua_S);
lua_register_cocos2dx_TMXLayerInfo(tolua_S);
lua_register_cocos2dx_EaseSineIn(tolua_S);
lua_register_cocos2dx_EaseBounceIn(tolua_S);
lua_register_cocos2dx_Camera(tolua_S);
lua_register_cocos2dx_TMXObjectGroup(tolua_S);
lua_register_cocos2dx_FastTMXTiledMap(tolua_S);
lua_register_cocos2dx_ParticleGalaxy(tolua_S);
lua_register_cocos2dx_Twirl(tolua_S);
lua_register_cocos2dx_MenuItemLabel(tolua_S);
lua_register_cocos2dx_EaseQuinticActionIn(tolua_S);
lua_register_cocos2dx_LayerColor(tolua_S);
lua_register_cocos2dx_FadeOutBLTiles(tolua_S);
lua_register_cocos2dx_LayerGradient(tolua_S);
lua_register_cocos2dx_EventListenerTouchAllAtOnce(tolua_S);
lua_register_cocos2dx_GLViewImpl(tolua_S);
lua_register_cocos2dx_ToggleVisibility(tolua_S);
lua_register_cocos2dx_Repeat(tolua_S);
lua_register_cocos2dx_TransitionFlipY(tolua_S);
lua_register_cocos2dx_TurnOffTiles(tolua_S);
lua_register_cocos2dx_TintTo(tolua_S);
lua_register_cocos2dx_EaseBackInOut(tolua_S);
lua_register_cocos2dx_TransitionFadeBL(tolua_S);
lua_register_cocos2dx_TargetedAction(tolua_S);
lua_register_cocos2dx_DrawNode(tolua_S);
lua_register_cocos2dx_TransitionTurnOffTiles(tolua_S);
lua_register_cocos2dx_RotateTo(tolua_S);
lua_register_cocos2dx_TransitionSplitRows(tolua_S);
lua_register_cocos2dx_Device(tolua_S);
lua_register_cocos2dx_TransitionProgressRadialCCW(tolua_S);
lua_register_cocos2dx_ScaleTo(tolua_S);
lua_register_cocos2dx_TransitionPageTurn(tolua_S);
lua_register_cocos2dx_RenderState(tolua_S);
lua_register_cocos2dx_Properties(tolua_S);
lua_register_cocos2dx_BezierBy(tolua_S);
lua_register_cocos2dx_BezierTo(tolua_S);
lua_register_cocos2dx_ParticleMeteor(tolua_S);
lua_register_cocos2dx_SpriteFrame(tolua_S);
lua_register_cocos2dx_Liquid(tolua_S);
lua_register_cocos2dx_UserDefault(tolua_S);
lua_register_cocos2dx_FastTMXLayer(tolua_S);
lua_register_cocos2dx_TransitionZoomFlipX(tolua_S);
lua_register_cocos2dx_EventFocus(tolua_S);
lua_register_cocos2dx_TransitionFade(tolua_S);
lua_register_cocos2dx_EaseQuinticActionInOut(tolua_S);
lua_register_cocos2dx_SpriteFrameCache(tolua_S);
lua_register_cocos2dx_PointLight(tolua_S);
lua_register_cocos2dx_TransitionCrossFade(tolua_S);
lua_register_cocos2dx_Ripple3D(tolua_S);
lua_register_cocos2dx_Lens3D(tolua_S);
lua_register_cocos2dx_EventListenerFocus(tolua_S);
lua_register_cocos2dx_Spawn(tolua_S);
lua_register_cocos2dx_EaseQuarticActionInOut(tolua_S);
lua_register_cocos2dx_ShakyTiles3D(tolua_S);
lua_register_cocos2dx_PageTurn3D(tolua_S);
lua_register_cocos2dx_PolygonInfo(tolua_S);
lua_register_cocos2dx_TransitionSlideInL(tolua_S);
lua_register_cocos2dx_TransitionSlideInT(tolua_S);
lua_register_cocos2dx_Grid3D(tolua_S);
lua_register_cocos2dx_EventListenerController(tolua_S);
lua_register_cocos2dx_TransitionProgressInOut(tolua_S);
lua_register_cocos2dx_EaseCubicActionInOut(tolua_S);
lua_register_cocos2dx_ParticleData(tolua_S);
lua_register_cocos2dx_EaseBackIn(tolua_S);
lua_register_cocos2dx_SplitRows(tolua_S);
lua_register_cocos2dx_Follow(tolua_S);
lua_register_cocos2dx_Animate(tolua_S);
lua_register_cocos2dx_ShuffleTiles(tolua_S);
lua_register_cocos2dx_CameraBackgroundSkyBoxBrush(tolua_S);
lua_register_cocos2dx_ProgressTimer(tolua_S);
lua_register_cocos2dx_EaseQuarticActionIn(tolua_S);
lua_register_cocos2dx_Menu(tolua_S);
lua_register_cocos2dx_EaseInOut(tolua_S);
lua_register_cocos2dx_TransitionZoomFlipY(tolua_S);
lua_register_cocos2dx_ScaleBy(tolua_S);
lua_register_cocos2dx_EventTouch(tolua_S);
lua_register_cocos2dx_Animation(tolua_S);
lua_register_cocos2dx_TMXMapInfo(tolua_S);
lua_register_cocos2dx_EaseExponentialIn(tolua_S);
lua_register_cocos2dx_ReuseGrid(tolua_S);
lua_register_cocos2dx_EaseQuinticActionOut(tolua_S);
lua_register_cocos2dx_EventDispatcher(tolua_S);
lua_register_cocos2dx_MenuItemAtlasFont(tolua_S);
lua_register_cocos2dx_ActionManager(tolua_S);
lua_register_cocos2dx_OrbitCamera(tolua_S);
lua_register_cocos2dx_ClippingRectangleNode(tolua_S);
lua_register_cocos2dx_EventCustom(tolua_S);
lua_register_cocos2dx_ParticleBatchNode(tolua_S);
lua_register_cocos2dx_Component(tolua_S);
lua_register_cocos2dx_EaseCubicActionOut(tolua_S);
lua_register_cocos2dx_EventListenerTouchOneByOne(tolua_S);
lua_register_cocos2dx_Renderer(tolua_S);
lua_register_cocos2dx_ParticleRain(tolua_S);
lua_register_cocos2dx_Waves(tolua_S);
lua_register_cocos2dx_ComponentLua(tolua_S);
lua_register_cocos2dx_MotionStreak3D(tolua_S);
lua_register_cocos2dx_EaseOut(tolua_S);
lua_register_cocos2dx_MenuItemFont(tolua_S);
lua_register_cocos2dx_TransitionFadeUp(tolua_S);
lua_register_cocos2dx_LayerRadialGradient(tolua_S);
lua_register_cocos2dx_EaseSineOut(tolua_S);
lua_register_cocos2dx_JumpTiles3D(tolua_S);
lua_register_cocos2dx_MenuItemToggle(tolua_S);
lua_register_cocos2dx_RemoveSelf(tolua_S);
lua_register_cocos2dx_SplitCols(tolua_S);
lua_register_cocos2dx_ProtectedNode(tolua_S);
lua_register_cocos2dx_MotionStreak(tolua_S);
lua_register_cocos2dx_RotateBy(tolua_S);
lua_register_cocos2dx_FileUtils(tolua_S);
lua_register_cocos2dx_Sprite(tolua_S);
lua_register_cocos2dx_ProgressTo(tolua_S);
lua_register_cocos2dx_TransitionProgressOutIn(tolua_S);
lua_register_cocos2dx_AnimationFrame(tolua_S);
lua_register_cocos2dx_Sequence(tolua_S);
lua_register_cocos2dx_Shaky3D(tolua_S);
lua_register_cocos2dx_TransitionProgressRadialCW(tolua_S);
lua_register_cocos2dx_EaseBounceInOut(tolua_S);
lua_register_cocos2dx_TransitionSlideInR(tolua_S);
lua_register_cocos2dx_AmbientLight(tolua_S);
lua_register_cocos2dx_ParallaxNode(tolua_S);
lua_register_cocos2dx_EaseQuadraticActionIn(tolua_S);
lua_register_cocos2dx_WavesTiles3D(tolua_S);
lua_register_cocos2dx_TransitionSlideInB(tolua_S);
lua_register_cocos2dx_Speed(tolua_S);
lua_register_cocos2dx_ShatteredTiles3D(tolua_S);
tolua_endmodule(tolua_S);
return 1;
}
在大量注册函数中寻找到关键方法lua_register_cocos2dx_Image：
int lua_register_cocos2dx_Image(lua_State* tolua_S)
{
tolua_usertype(tolua_S,"cc.Image");
tolua_cclass(tolua_S,"Image","cc.Image","cc.Ref",nullptr);
tolua_beginmodule(tolua_S,"Image");
tolua_function(tolua_S,"new",lua_cocos2dx_Image_constructor);
tolua_function(tolua_S,"hasPremultipliedAlpha",lua_cocos2dx_Image_hasPremultipliedAlpha);
tolua_function(tolua_S,"reversePremultipliedAlpha",lua_cocos2dx_Image_reversePremultipliedAlpha);
tolua_function(tolua_S,"isCompressed",lua_cocos2dx_Image_isCompressed);
tolua_function(tolua_S,"hasAlpha",lua_cocos2dx_Image_hasAlpha);
tolua_function(tolua_S,"getPixelFormat",lua_cocos2dx_Image_getPixelFormat);
tolua_function(tolua_S,"getHeight",lua_cocos2dx_Image_getHeight);
tolua_function(tolua_S,"premultiplyAlpha",lua_cocos2dx_Image_premultiplyAlpha);
tolua_function(tolua_S,"initWithImageFile",lua_cocos2dx_Image_initWithImageFile); // 初始化图片文件
tolua_function(tolua_S,"getWidth",lua_cocos2dx_Image_getWidth);
tolua_function(tolua_S,"getBitPerPixel",lua_cocos2dx_Image_getBitPerPixel);
tolua_function(tolua_S,"getFileType",lua_cocos2dx_Image_getFileType);
tolua_function(tolua_S,"getFilePath",lua_cocos2dx_Image_getFilePath);
tolua_function(tolua_S,"getNumberOfMipmaps",lua_cocos2dx_Image_getNumberOfMipmaps);
tolua_function(tolua_S,"saveToFile",lua_cocos2dx_Image_saveToFile);
tolua_function(tolua_S,"setPVRImagesHavePremultipliedAlpha", lua_cocos2dx_Image_setPVRImagesHavePremultipliedAlpha);
tolua_function(tolua_S,"setPNGPremultipliedAlphaEnabled", lua_cocos2dx_Image_setPNGPremultipliedAlphaEnabled);
tolua_endmodule(tolua_S);
std::string typeName = typeid(cocos2d::Image).name();
g_luaType[typeName] = "cc.Image";
g_typeCast["Image"] = "cc.Image";
return 1;
}
lua_cocos2dx_Image_initWithImageFile加载了我们的图片文件。
int lua_cocos2dx_Image_initWithImageFile(lua_State* tolua_S)
{
int argc = 0;
cocos2d::Image* cobj = nullptr;
bool ok = true;
#if COCOS2D_DEBUG >= 1
tolua_Error tolua_err;
#endif
#if COCOS2D_DEBUG >= 1
if (!tolua_isusertype(tolua_S,1,"cc.Image",0,&tolua_err)) goto tolua_lerror;
#endif
cobj = (cocos2d::Image*)tolua_tousertype(tolua_S,1,0);
#if COCOS2D_DEBUG >= 1
if (!cobj)
{
tolua_error(tolua_S,"invalid 'cobj' in function 'lua_cocos2dx_Image_initWithImageFile'", nullptr);
return 0;
}
#endif
argc = lua_gettop(tolua_S)-1;
if (argc == 1)
{
std::string arg0;
ok &= luaval_to_std_string(tolua_S, 2,&arg0, "cc.Image:initWithImageFile");
if(!ok)
{
tolua_error(tolua_S,"invalid arguments in function 'lua_cocos2dx_Image_initWithImageFile'", nullptr);
return 0;
}
bool ret = cobj->initWithImageFile(arg0);
tolua_pushboolean(tolua_S,(bool)ret);
return 1;
}
luaL_error(tolua_S, "%s has wrong number of arguments: %d, was expecting %d \n", "cc.Image:initWithImageFile",argc, 1);
return 0;
#if COCOS2D_DEBUG >= 1
tolua_lerror:
tolua_error(tolua_S,"#ferror in function 'lua_cocos2dx_Image_initWithImageFile'.",&tolua_err);
#endif
return 0;
}
下面看cobj->initWithImageFile：
bool Image::initWithImageFile(const std::string& path)
{
bool ret = false;
_filePath = FileUtils::getInstance()->fullPathForFilename(path);
Data data = FileUtils::getInstance()->getDataFromFile(_filePath); // 获取文件数据
if (!data.isNull())
{
ret = initWithImageData(data.getBytes(), data.getSize()); // 解码/解密 处理文件数据
}
return ret;
}
下面是图片数据格式解码方法initWithImageData
bool Image::initWithImageData(const unsigned char * data, ssize_t dataLen)
{
bool ret = false;
do
{
CC_BREAK_IF(! data || dataLen <= 0);
unsigned char* unpackedData = nullptr;
ssize_t unpackedLen = 0;
//detect and unzip the compress file
if (ZipUtils::isCCZBuffer(data, dataLen))
{
unpackedLen = ZipUtils::inflateCCZBuffer(data, dataLen, &unpackedData);
}
else if (ZipUtils::isGZipBuffer(data, dataLen))
{
unpackedLen = ZipUtils::inflateMemory(const_cast<unsigned char*>(data), dataLen, &unpackedData);
}
else
{
unpackedData = const_cast<unsigned char*>(data);
unpackedLen = dataLen;
}
_fileType = detectFormat(unpackedData, unpackedLen);
switch (_fileType)
{
case Format::PNG:
ret = initWithPngData(unpackedData, unpackedLen);
break;
case Format::JPG:
ret = initWithJpgData(unpackedData, unpackedLen);
break;
case Format::WEBP:
ret = initWithWebpData(unpackedData, unpackedLen);
break;
case Format::PVR:
ret = initWithPVRData(unpackedData, unpackedLen);
break;
case Format::ETC:
ret = initWithETCData(unpackedData, unpackedLen);
break;
case Format::S3TC:
ret = initWithS3TCData(unpackedData, unpackedLen);
break;
case Format::ATITC:
ret = initWithATITCData(unpackedData, unpackedLen);
break;
default:
{
// load and detect image format
tImageTGA* tgaData = tgaLoadBuffer(unpackedData, unpackedLen);
if (tgaData != nullptr && tgaData->status == TGA_OK)
{
ret = initWithTGAData(tgaData);
}
else
{
CCLOG("cocos2d: unsupported image format!");
}
free(tgaData);
break;
}
}
if(unpackedData != data)
{
free(unpackedData);
}
} while (0);
return ret;
}
图片资源的加载到这里就结束了。
快速定位：根据调用流程，我们可以直接定位方法cocos2d::Image::initWithImageData。
向上可以追溯到cocos2d::Image::initWithImageFile：
看到了可疑函数cocos2d::Image::decodePngData
cocos2d *__fastcall cocos2d::Image::decodePngData(cocos2d::Image *this, cocos2d::Data *a2)
{
_BYTE *v4; // r7
int v5; // r5
signed int v6; // r0
bool v7; // cc
int v8; // r4
void *v9; // r0
int v10; // r2
int v12; // r6
int v13; // r4
int v14; // r9
int v15; // r2
int v16; // r0
int v17; // r3
_BYTE *v18; // r5
unsigned int *v19; // r2
int v20; // r3
int v21; // [sp+8h] [bp-28h] BYREF
v4 = (_BYTE *)cocos2d::Data::getBytes(a2);
v5 = cocos2d::Data::getSize(a2);
sub_FBDCA8(&v21, (int *)this + 47);
v6 = sub_FBC854((int)&v21, ".png", 0, 4u);
v7 = v6 <= -1;
if ( v6 != -1 )
v7 = v5 <= 24;
v8 = !v7;
v9 = (void *)(v21 - 12);
if ( (int *)(v21 - 12) != &dword_12F6978 )
{
if ( &pthread_create )
{
v19 = (unsigned int *)(v21 - 4);
__dmb(0xFu);
do
v20 = __ldrex(v19);
while ( __strex(v20 - 1, v19) );
__dmb(0xFu);
}
else
{
v20 = *(_DWORD *)(v21 - 4);
*(_DWORD *)(v21 - 4) = v20 - 1;
}
if ( v20 <= 0 )
operator delete(v9);
}
if ( v8 && memcmp(&unk_11CBE0C, v4, 8u) ) // PNG Header
{
v12 = v5 - 4;
v13 = v5 - 8;
v14 = cocos2d::hexToDecimal((cocos2d *)&v4[v5 - 4], (unsigned __int8 *)&byte_4, v10);
v16 = cocos2d::hexToDecimal((cocos2d *)&v4[v5 - 8], (unsigned __int8 *)&byte_4, v15);
if ( v5 >= v16 )
cocos2d::decodePng(v4, (unsigned __int8 *)(v14 - 2048), v16, v17);
v18 = &v4[v5];
*(v18 - 1) = 130;
*(v18 - 2) = 96;
*(v18 - 3) = 66;
v4[v12] = 174;
*(v18 - 5) = 68;
*(v18 - 6) = 78;
*(v18 - 7) = 69;
v4[v13] = 73;
}
return (cocos2d *)v4;
}
明显是一个算法函数，看方法cocos2d::decodePng：
_BYTE *__fastcall cocos2d::decodePng(_BYTE *this, unsigned __int8 *a2, int a3, int a4)
{
char v4; // r12
unsigned int v5; // r1
int v6; // r12
char v7[4]; // [sp+0h] [bp-10h]
v7[1] = BYTE2(a2);
v4 = BYTE1(a2);
v7[3] = (char)a2;
v5 = (unsigned int)a2 >> 24;
v7[2] = v4;
v6 = 0;
v7[0] = v5;
if ( a3 > 0 )
{
while ( 1 )
{
++v6;
*this++ ^= v5;
if ( v6 == a3 )
break;
LOBYTE(v5) = v7[v6 % 4];
}
}
return this;
}
这里也可以尝试Frida Hook验证猜想，同样的，我就不Hook了。算法还原
def _hexToDecimal(data, offset):
if offset <= 0:
return 0
return struct.unpack(">I", data[:offset])[0]
def LOBYTE(d):
return d & 0xff
def _decodePng(data, magic, rounds):
dthis = bytearray(data)
v7 = [0] * 4
a2 = struct.pack("<i", magic)
v7[1] = a2[2]
v7[3] = a2[0]
v7[0] = v5 = magic >> 24
v7[2] = a2[1]
i = 0
if rounds > 0:
while 1:
i += 1
dthis[i-1] ^= v5
if i == rounds:
break
v5 = LOBYTE(v7[i % 4])
return dthis
def decodePng(data, size):
v14 = _hexToDecimal(data[-4:], 4)
v16 = _hexToDecimal(data[-8:], 4)
if size >= v16:
ret = _decodePng(data, v14 - 2048, v16)
ret[-1] = 130
ret[-2] = 96
ret[-3] = 66
ret[-4] = 174
ret[-5] = 68
ret[-6] = 78
ret[-7] = 69
ret[-8] = 73
return ret
解密结果：
标签：cocos2dx,lua,int,Image,register,解密,Lua,Cocos2dlua,tolua From： https://www.cnblogs.com/sevck/p/18181632