CMake Build Scripts for GDNative C++ Bindings
This repo contains CMake scripts to ease cross-platform building of GDNative C++ bindings.
Supported platforms:
- Windows & Linux
- Android (Android NDK)
- WebAssembly (Emscripten)
Requires at least Godot Engine 3.1 with support for NativeScript 1.1, but may work with older Godot Engine releases.
Clone this repo with --recurse-submodules option. It'll clone this repo with all required dependencies such as godot-cpp and godot_headers direct from github's repository.
Prerequisites
Before start building, you need CMake 3.10+ build scripts generator, Python for GDNative C++ bindings' generator and Android SDK with NDK bundle installed. Optionally, you can use Ninja build system - my personal choice - but these CMake scripts should work with any build system supported by your environment.
Compiling
It's advisable to create separate subdirectories for each target platforms inside /build directory. For example, for Windows x64 build, name the subdirectory as win64 and open it within Command Prompt (or Terminal, depends on your OS). For MSVC build, use MSVC's Native Command Prompt (x86 or x64). After the preparation, generate build scripts being inside the platform build directory using CMake as:
cd build\win64
cmake -G Ninja ..\.. -DGODOT_API_JSON=C:\Path\To\godot_api.json
This should work with Linux the same way. But for Android, it isn't more complicated. Bur first, you should ensure that you're having the latest NDK (tested on r19) version installed on your system with CMake toolchain file bundled. Assuming you have configured Android SDK properly, you can run the CMake tool with specified definitions:
cd build\android
cmake -G Ninja ..\.. -DCMAKE_SYSTEM_NAME=Android -DGODOT_API_JSON=C:\Path\To\godot_api.json
For Android build, CMake's script tries to find Android NDK's CMake Toolchain automatically using ANDROID_NDK_ROOT environment variable. Ensure first, that it's available on your system. Also remember to use -DCMAKE_SYSTEM_NAME=Android flag, as it does Android build scripts preparation.
Experimental Emscripten build is also available, but GDNative on JavaScript platform is currently not officialy supported by Godot Engine developers. To generate build scripts for Emscripten, use -DCMAKE_SYSTEM_NAME=Emscripten flag. As like for Android target, CMake's script will try to find Emscripten's toolchain using EMSCRIPTEN environment variable.
If you wish, you can supply toolchain file manually by defining CMAKE_TOOLCHAIN_FILE variable yourself.
To generate build scripts for release (optimized) targets, use CMake's -DCMAKE_BUILD_TYPE option as -DCMAKE_BUILD_TYPE=Release. Built libraries should be located under /lib root directory. Emscripten have special MinSizeRel build type, as it builds the library in favour of minimizing the library size also the performance loss is minimal.
Troubleshooting
If you don't know how to obtain the godot_api.json file, just run Godot.exe within Command Prompt with --gdnative-generate-json-api option, just like:
Godot.exe --gdnative-generate-json-api godot_api.json
Generated godot_api.json file should be located inside the same directtory as Godot executable.