cocos2dx lua 绑定详解与实战

我们平时在开发cocos2dx lua游戏的时候的，会遇到这样的情况：

在c++层定义了一些类，我们需要将这些类导出给Lua来使用，从而完成在c++层实现起来容易的需求，这个时候就需要将整个类作为模块导出。

而Cocos2d-x正是采用的这种思想，将Cocos中的类导出供用户使用，而不是再写一套Lua代码，用户使用Cocos导出的这套接口，在Lua脚本层写游戏代码。

为了更好的理解这部分的内容，可以先了解c++中调用Lua的机制。

推荐

前面文章中，我们说到了，Lua的本质是C，不是C++，Lua提供给C用的API也都是基于面向过程的C函数来用的，要把C++类注册进Lua形成一个一个的table环境是不太容易一下子办到的事。

为了实现我们的需求，同样也是官方的需求，在Cocos 2.x版本的时候，使用的是tolua++这个工具，但是这个工具用起来相当的麻烦，耗费体力，所以现在使用的是bindings-generator工具（官方用Python写的一个工具），这个东西底层使用的也应该是tolua++。

这里只针对iOS平台，Android和其他平台在tolua中README.mdown中有具体介绍，其他步骤基本上一样！

在项目跟目录framework/cocos2d-x/cocos中创建mybinding文件夹，里面创建一个MyBinding.h文件(mybinding, MyBinding自定义)，输入如下测试代码

#include "cocos2d.h"
namespace cocos2d {

class MyBinding: public Ref {

public:
virtual bool init() {

return true;

}
void sayBinding() {

log("Hello Binding Lua");

}
MyBinding();

~MyBinding();

}

}

在framework/cocos2d-x/tools/tolua，新建一个配置文件，这里命名cocos2dx_binding.ini

输入下面代码：（处理标记修改处其他所有都一样）

[cocos2dx_binding] # 标记修改
# the prefix to be added to the generated functions. You might or might not use this in your own
# templates
prefix = cocos2dx_binding # 标记修改
 create a target namespace (in javascript, this would create some code like the equiv. to ns = ns || {})
 all classes will be embedded in that namespace
target_namespace = cc # 标记修改
 --------- ?
#android_headers = -I%(androidndkdir)s/platforms/android-19/arch-arm/usr/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.7/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.7/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.8/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.8/include

android_headers = -I%(androidndkdir)s/platforms/android-19/arch-arm/usr/lib -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/include
 --------- ?
android_flags = -D_SIZE_T_DEFINED_
#clang_headers = -I%(clangllvmdir)s/lib/clang/%(clang_version)s/include

clang_headers = -I%(clangllvmdir)s/lib64/clang/5.0/include

clang_flags = -nostdinc -x c++ -std=c++11 -U SSE
 --------- ?
 -I%(cocosdir)s/jsext -I%(cocosdir)s/jsext/system -I%(cocosdir)s/jsext/alipay  -I%(cocosdir)s/jsext/video -I%(cocosdir)s/jsext/webview -I%(cocosdir)s/jsext/umeng
cocos_headers = -I%(cocosdir)s -I%(cocosdir)s/cocos -I%(cocosdir)s/cocos/base -I%(cocosdir)s/cocos/platform/android -I%(cocosdir)s/extensions -I%(cocosdir)s/external -I%(cocosdir)s/cocos/editor-support -I%(cocosdir)s/cocos/network -I%(cocosdir)s/cocos/ui/UIEditBox -I%(cocosdir)s/cocos/ui

#cocos_headers = -I%(cocosdir)s -I%(cocosdir)s/cocos -I%(cocosdir)s/cocos/platform/android
cocos_flags = -DANDROID
cxxgenerator_headers =
 extra arguments for clang
extra_arguments = %(android_headers)s %(clang_headers)s %(cxxgenerator_headers)s %(cocos_headers)s %(android_flags)s %(clang_flags)s %(cocos_flags)s %(extra_flags)s
 what headers to parse 头文件路径
headers = %(cocosdir)s/cocos/mybinding/MyBinding.h # 标记修改
 what classes to produce code for. You can use regular expressions here. When testing the regular
 expression, it will be enclosed in "^", like this: "^Menu*".
#包含的类，新添加文件需要修改

classes = MyBinding.* # 标记修改
#需要在js里面派生的类

#classes_need_extend = MyBinding # 标记修改
 what should we skip? in the format ClassName::[function function]
 ClassName is a regular expression, but will be used like this: "^ClassName$" functions are also
 regular expressions, they will not be surrounded by "^$". If you want to skip a whole class, just
 add a single "" as functions. See bellow for several examples. A special class name is "", which
 will apply to all class names. This is a convenience wildcard to be able to skip similar named
 functions from all classes.
skip =
rename_functions =
rename_classes =
 for all class names, should we remove something when registering in the target VM?
remove_prefix =
 classes for which there will be no "parent" lookup
classes_have_no_parents =
 base classes which will be skipped when their sub-classes found them.
base_classes_to_skip = Ref
 classes that create no constructor
 Set is special and we will use a hand-written constructor
abstract_classes =
 Determining whether to use script object(js object) to control the lifecycle of native(cpp) object or the other way around. Supported values are 'yes' or 'no'.
script_control_cpp = no

注意检查一下三个头文件对应的路径及文件问题

android_headers
clang_headers
cocos_headers

说明内容：

+ •[title]：要配置将被使用的工具/ tolua的/ gengindings.py脚本的称号。一般来说，标题可以是文件名。
+ •prefix：要配置一个函数名的前缀，通常，我们还可以使用文件名作为前缀。
+ •target_namespace：要配置在脚本层模块的名字。在这里，我们使用cc作为模块名，当你想在脚本层REF的名称，您必须将一个名为前缀，CC在名称的前面。例如，CustomClass可以参考作为cc.CustomClass。
+ •headers：要配置所有需要解析的头文件和％（cocosdir）s是的Cocos2d-x的引擎的根路径。
+ •classes：要配置所有绑定所需的类。在这里，它支持正则表达式。因此，我们可以设置MyCustomClass。*在这里，用于查找多个特定的用法，你可以对照到tools/tolua/cocos2dx.ini。
+ •skip：要配置需要被忽略的功能。现在绑定发电机无法解析的void *类型，并委托类型，所以这些类型的需要进行手动绑定。而在这种情况下，你应该忽略所有这些类型，然后再手动将它们绑定。你可以对照到配置文件路径下的cocos/scripting/lua-bindings/auto 。
+ •rename_functions：要配置的功能需要在脚本层进行重命名。由于某些原因，开发者希望更多的脚本友好的API，所以配置选项就是为了这个目的。
+ •rename_classes：不在使用。
+ •remove_prefix：不在使用。
+ •classes_have_no_parents：要配置是过滤器所需要的父类。这个选项是很少修改。
+ •abstract_classes：要配置的公共构造并不需要导出的类。
+ •script_control_cpp：是的。要配置脚本层是否管理对象的生命周期。如果没有，那么C++层关心他们的生命周期。现在，它是不完善的，以控制原生对象的续航时间在脚本层。所以，你可以简单地把它设置为no

修改framework/cocos2d-x/tools/tolua里面的genbindings.py。有个cmd_args键值对的配置，增加下面代码，作为自定义绑定配置

'cocos2dx_binding.ini' : ('cocos2dx_binding', 'lua_cocos2dx_binding_auto'),

注：python注释为#，这里将cmd_args其他的元素注释掉是因为这些文件都是生成过得，没必要再生成浪费时间
这行代码表示在cocos2dx_custom中找到cocos2dx_custom的模块，然后生成lua_cocos2dx_custom_auto文件

这里要确保NDK_ROOT，和PYTHON_BIN安装切配置好了,然后在framework/cocos2d-x/tools/tolua执行

./genbindings.py

之前./genbindings.py之前，请先查看官方tolua中README文件，按照对应的流程，安装好需要的依赖，和相应的库，下面是我这边3.17最新的README

* The OSX 10.1<!--0 has a built-in python2.7 and if your os don't have python2.7 then use [Homebrew](http://brew.sh/) to install the python and use pip install the python dependencies.
<pre>
brew install python
</pre>


Install python dependices by pip.

<pre>

sudo easy_install pip

sudo pip install PyYAML

sudo pip install Cheetah

</pre>


Download NDK 64bit r10c or later from Android Ndk


Run

<pre>

export NDK_ROOT=/path/to/android-ndk-10c

./genbindings.py

</pre>–>

大概意思就是下载r10c之后版的NDK本，然后安装python(这一步一般Mac都有，但是最好安装到2.x)。

大概意思就是安装，pip， PyYAML， Cheetah

…….

执行./genbindings.py之后生成在

工程目录frameworkscocos2d-xcocosscriptinglua-bindingsauto

下便有了两个生成的文件

lua_cocos2dx_custom_auto.cpp
lua_cocos2dx_custom_auto.hpp

进入到文件夹

C:UsersuserDocumentsCocosLinkframeworkscocos2d-xcocosscriptinglua-bindingsmanual 打开CCLuaStack.cpp，添加

#include "lua_cocos2dx_custom_auto.hpp" register_all_cocos2dx_custom(_state);

期间遇到的错误

错误一

Traceback (most recent call last):

File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1799, in <module>

main()

File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1772, in main

'clang_args': (config.get(s, 'extra_arguments', 0, dict(userconfig.items('DEFAULT'))) or "").split(" "),

File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ConfigParser.py", line 623, in get

return self._interpolate(section, option, value, d)

File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ConfigParser.py", line 691, in _interpolate

self._interpolate_some(option, L, rawval, section, vars, 1)

File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ConfigParser.py", line 726, in _interpolate_some

section, map, depth + 1)

File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ConfigParser.py", line 723, in _interpolate_some

option, section, rest, var)

InterpolationMissingOptionError: Bad value substitution:

section: [cocos2dx_custom]

option : extra_arguments

key    : clang_version

rawval : /include

路径错误

#clang_headers = -I%(clangllvmdir)s/lib/clang/%(clang_version)s/include
clang_headers = -I%(clangllvmdir)s/lib64/clang/5.0/include  # --------- ?

错误二

Traceback (most recent call last): File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1799, in <module> main() File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1795, in main generator.generate_code() File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1444, in generate_code self._parse_headers() File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1487, in _parse_headers raise Exception("Fatal error in parsing headers") Exception: Fatal error in parsing headers Generating lua bindings fails.

C++语法错误

错误三

Generating bindings for cocos2dx_custom... Using userconfig [('androidndkdir', '/Users/iCocos/tools/android-ndk-r16b'), ('clangllvmdir', '/Users/iCocos/tools/android-ndk-r16b/toolchains/llvm/prebuilt/darwin-x86_64'), ('gcc_toolchain_dir', '/Users/iCocos/tools/android-ndk-r16b/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64'), ('cocosdir', '/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x'), ('cxxgeneratordir', '/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator'), ('extra_flags', '')] … Generating bindings for target lua … … Processing section cocos2dx_custom Traceback (most recent call last): File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1799, in <module> main() File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1795, in main generator.generate_code() File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1444, in generate_code self._parse_headers() File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/generator.py", line 1478, in _parse_headers tu = self.index.parse(header, self.clang_args) File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/clang/cindex.py", line 2602, in parse self) File "/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/tools/bindings-generator/clang/cindex.py", line 2714, in from_source raise TranslationUnitLoadError("Error parsing translation unit.") TranslationUnitLoadError: Error parsing translation unit. Generating lua bindings fails.

路径错误

#android_headers = -I%(androidndkdir)s/platforms/android-19/arch-arm/usr/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.7/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.7/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.8/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.8/include
android_headers = -I%(androidndkdir)s/platforms/android-19/arch-arm/usr/lib -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi-v7a/include -I%(androidndkdir)s/sources/cxx-stl/gnu-libstdc++/4.9/include

错误四

====
Errors in parsing headers:


<severity = Fatal,

location = <SourceLocation file '/Users/iCocos/Desktop/cocos2d/Products/cocos2dx-demo/SingleLua/frameworks/cocos2d-x/cocos/platform/android/CCPlatformDefine-android.h', line 33, column 10>,

details = "'android/log.h' file not found">

====

……

提示成功

---------------------------------
Generating lua bindings succeeds.
---------------------------------

拓展推荐

lua： http://www.lua.org/
- lua是个脚本语言，脚本语言！！就是脚本文件加解释器。之后你就可以看效果了。可是呢，lua如果正是靠自己独立完成点事情，那就是大材小用，需要和其他东西结合起来，比如C/C++.貌似主要也就是C/C++。
tolua++： http://www.codenix.com/~tolua/#news
- tolua++：首先看名字“到、lua、++”，就是把其他语言（C/C++函数对象转化为lua能调用形式，++这里理解为增强版），有了这个工具，我们就可以快速的将我们现成的C/C++代码封装成Lua接口形式。
luajit： http://luajit.org/luajit.html
- LuaJIT：LuaJIT is a Just-In-Time Compiler (JIT) for the Lua programming language. 。。。。。。说了半天就一个lua的高效率版本。
lua for windows： http://luaforge.net/projects/luaforwindows/
- lua for windows：lua在windows下的打包版本，除了最基本的lua解释器，还包括了可用于和C/C++集成开发的【动态链接库、静态链接库、头文件】、文本编辑器、常用的lua module，帮助说明文档。

cocos2dx lua 绑定详解与实战

推荐

create a target namespace (in javascript, this would create some code like the equiv. to `ns = ns || {}`)

all classes will be embedded in that namespace

--------- ?

--------- ?

--------- ?

-I%(cocosdir)s/jsext -I%(cocosdir)s/jsext/system -I%(cocosdir)s/jsext/alipay -I%(cocosdir)s/jsext/video -I%(cocosdir)s/jsext/webview -I%(cocosdir)s/jsext/umeng

extra arguments for clang

what headers to parse 头文件路径

what classes to produce code for. You can use regular expressions here. When testing the regular

expression, it will be enclosed in "^", like this: "^Menu*".

what should we skip? in the format ClassName::[function function]

ClassName is a regular expression, but will be used like this: "^ClassName$" functions are also

regular expressions, they will not be surrounded by "^$". If you want to skip a whole class, just

add a single "" as functions. See bellow for several examples. A special class name is "", which

will apply to all class names. This is a convenience wildcard to be able to skip similar named

functions from all classes.

for all class names, should we remove something when registering in the target VM?

classes for which there will be no "parent" lookup

base classes which will be skipped when their sub-classes found them.

classes that create no constructor

Set is special and we will use a hand-written constructor

Determining whether to use script object(js object) to control the lifecycle of native(cpp) object or the other way around. Supported values are 'yes' or 'no'.

说明内容：

期间遇到的错误

错误一

错误二

Generating lua bindings fails.

错误三

Generating lua bindings fails.

错误四

提示成功

拓展推荐

致谢：