godot-cpp

[!WARNING]

This repository's master branch is only usable with GDExtension from Godot's master branch.

For users of stable branches, switch to the branch matching your target Godot version:

• 4.2
• 4.1
• 4.0

Or check out the Git tag matching your Godot version (e.g. godot-4.1.1-stable).

For GDNative users (Godot 3.x), switch to the 3.x or the 3.5 branch.

This repository contains the C++ bindings for the Godot Engine's GDExtensions API.

• Versioning
• Compatibility
• Contributing
• Getting started
• Examples and templates

Versioning

This repositories follows the same branch versioning as the main Godot Engine repository:

• master tracks the current GDExtension development branch for the next Godot 4.x minor release.
• 3.x tracks the development of the GDNative plugin for the next 3.x minor release.
• Other versioned branches (e.g. 4.0, 3.5) track the latest stable release in the corresponding branch.

Stable releases are also tagged on this repository: Tags.

For any project built against a stable release of Godot, we recommend using this repository as a Git submodule, checking out the specific tag matching your Godot version.

As the master branch of Godot is constantly getting updated, if you are using godot-cpp against a more current version of Godot, see the instructions in the gdextension folder to update the relevant files.

Compatibility

[!WARNING]

The GDExtension API is brand new in Godot 4.0, and is still considered in beta stage, despite Godot 4.0 itself being released.

This applies to both the GDExtension interface header, the API JSON, and this first-party godot-cpp extension.

Some compatibility breakage is to be expected as GDExtension and godot-cpp get more used, documented, and critical issues get resolved. See the Godot issue tracker and the godot-cpp issue tracker for a list of known issues, and be sure to provide feedback on issues and PRs which affect your use of this extension.

Contributing

We greatly appreciate help in maintaining and extending this project. If you wish to help out, ensure you have an account on GitHub and create a "fork" of this repository. See Pull request workflow for instructions.

Please install clang-format and copy the files in misc/hooks into .git/hooks so formatting is done before your changes are submitted.

Getting started

You need the same C++ pre-requisites installed that are required for the godot repository. Follow the official build instructions for your target platform.

Getting started with GDExtensions is a bit similar to what it was for 3.x but also a bit different.

This new approach is much more akin to how core Godot modules are structured.

Compiling this repository generates a static library to be linked with your shared lib, just like before.

To use the shared lib in your Godot project you'll need a .gdextension file, which replaces what was the .gdnlib before. See example.gdextension used in the test project:

[configuration]

entry_symbol = "example_library_init"
compatibility_minimum = "4.1"

[libraries]

macos.debug = "res://bin/libgdexample.macos.debug.framework"
macos.release = "res://bin/libgdexample.macos.release.framework"
windows.debug.x86_64 = "res://bin/libgdexample.windows.debug.x86_64.dll"
windows.release.x86_64 = "res://bin/libgdexample.windows.release.x86_64.dll"
linux.debug.x86_64 = "res://bin/libgdexample.linux.debug.x86_64.so"
linux.release.x86_64 = "res://bin/libgdexample.linux.release.x86_64.so"
# Repeat for other architectures to support arm64, rv64, etc.

The entry_symbol is the name of the function that initializes your library. It should be similar to following layout:

extern "C" {

// Initialization.

GDExtensionBool GDE_EXPORT example_library_init(GDExtensionInterfaceGetProcAddress p_get_proc_address, GDExtensionClassLibraryPtr p_library, GDExtensionInitialization *r_initialization) {
	godot::GDExtensionBinding::InitObject init_obj(p_get_proc_address, p_library, r_initialization);

	init_obj.register_initializer(initialize_example_module);
	init_obj.register_terminator(uninitialize_example_module);
	init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);

	return init_obj.init();
}
}

The initialize_example_module() should register the classes in ClassDB, very like a Godot module would do.

using namespace godot;
void initialize_example_module(ModuleInitializationLevel p_level) {
	if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
		return;
	}
	GDREGISTER_CLASS(Example);
}

Any node and resource you register will be available in the corresponding Create... dialog. Any class will be available to scripting as well.

Examples and templates

See the godot-cpp-template project for a generic reusable template.

Or checkout the code for the Summator example as shown in the official documentation.

Godot and Godot Cpp Compatibility

If you intend to target both building as a GDExtension and as a module using godot repo, you can generate compatibility includes that will target either GDExtension or module, based on the GODOT_MODULE define.

If you want such headers, when running the build command, scons, pass the godot_repo param with the path to the godot repository. Eg. if you have the godot repository cloned at path ../godot, then do:

scons godot_repo="../godot"

This will generate something like this:

gen/include/godot_cpp/..
gen/include/godot_compat/..

Now, all you need to do is when writing your addon/module, replace includes like these:

#include <godot_cpp/classes/a_star_grid2d.hpp>

with

#include <godot_compat/classes/a_star_grid2d.hpp>

Inside, this file will have code for both godot and godot-cpp:

#ifdef GODOT_MODULE
#include <core/math/a_star_grid_2d.h>
#else
#include <godot_cpp/classes/a_star_grid2d.hpp>
#endif

Manually generate mapping files

The mappings can be manually generated by running the compat_generator.py script.

Example of how to run compat_generator.py:

git clone godotengine/godot
python compat_generator.py godot

The first argument of compat_generator.py is the folder where the repo is (can be godot or godot-cpp repo). If this folder is not given, the current directory is assumed. The output of this is either output_header_mapping_godot.json or output_header_mapping_godot_cpp.json

Manually match the mapping files

If you want to manually match the godot mapping file with the godot-cpp one, you can do that by running:

python header_matcher.py

This will generate the header_matches.json file with matches from godot and godot_cpp repo.