Revision Difference
Creating_Binary_Modules#514147
<cat>Dev</cat>⤶
Binary modules allow you to extend Lua's functionality using C++. ⤶
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# Headers⤶
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The headers you need and an example are [available here](https://github.com/Facepunch/gmod-module-base/tree/development). ⤶
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# Building⤶
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To turn the example into a visual studio project you should download [premake4](https://github.com/premake/premake-core), place the premake5.exe file in the same directory as BuildProjects.bat (or ideally in your main windows folder), and then run BuildProjects.bat. ⤶
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This will then create a folder called "windows-vs2010", which contains the Visual Studio project file.⤶
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Read up on how to use [Premake](https://github.com/premake/premake-core/wiki) to compile your modules for osx/linux.⤶
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# A note on userdata & metatables⤶
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Userdata and metatables are handled differently in Garry's Mod. This helps the engine determine userdata type much faster.⤶
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First create your metatable (ideally in GMOD_MODULE_OPEN), then create a reference to it and store it globally in a variable.⤶
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```⤶
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LUA->CreateTable();⤶
```⤶
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```⤶
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LUA->PushCFunction(gcDeleteWrapper);⤶
LUA->SetField(-2, "__gc");⤶
```⤶
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```⤶
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LUA->PushCFunction(toStringWrapper);⤶
LUA->SetField(-2, "__tostring");⤶
```⤶
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```⤶
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LUA->PushCFunction(indexWrapper);⤶
LUA->SetField(-2, "__index");⤶
```⤶
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```⤶
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LUA->PushCFunction(newIndexWrapper);⤶
LUA->SetField(-2, "__newindex");⤶
```⤶
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```⤶
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metatable = LUA->ReferenceCreate();⤶
```⤶
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To push your userdata to the stack:⤶
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```⤶
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GarrysMod::Lua::UserData* ud = ( GarrysMod::Lua::UserData* )LUA->NewUserdata( sizeof( GarrysMod::Lua::UserData ) );⤶
ud->data = pointer_to_your_c_class;⤶
ud->type = your_type_id;⤶
LUA->ReferencePush( metatable );⤶
LUA->SetMetaTable(-2);⤶
```⤶
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To get your userdata from the stack:⤶
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```⤶
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GarrysMod::Lua::UserData* obj = (GarrysMod::Lua::UserData* )LUA->GetUserdata(position);⤶
your_c_class* var = (your_c_class*)(obj->data);⤶
```⤶
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# Naming & Location⤶
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The module files should be placed in the garrysmod/lua/bin/ folder.⤶
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The names differ between platform and Lua realm.⤶
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* gmcl_example_win32.dll - windows clientside module⤶
* gmsv_example_win32.dll - windows serverside/menu state module⤶
* gmcl_example_osx.dll - osx clientside module⤶
* gmsv_example_linux.dll - linux serverside/menu state module⤶
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# Converting From GMod 12⤶
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The interface in GMod 13 is very different to that of GMod 12 - the handy object wrappers are gone and the interface is very very similar to the standard Lua C API. Infact, nearly all of the functions in the interface work exactly the same way as their equivalents in the Lua C API, they're just named slightly differently.⤶
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You should be able to work out what most of the functions do from the example and the [Lua C API Documentation](http://www.lua.org/manual/5.2/manual.html#4.8). ⤶
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If you find this kind of stack-level programming too hard, BlackAwps has created some "backwards headers", which should work exactly how the GMod 12 interface worked, you can find them [here](https://bitbucket.org/breakpointservers/bkacjios-glua-modules/src).⤶
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