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@ -1,5 +1,6 @@
# godot-cpp # godot-cpp
C++ bindings for the Godot script API
**C++ bindings for the Godot script API.**
The instructions below feature the new NativeScript 1.1 class structure and will only work for modules created for Godot 3.1 and later. Use the following branches for older implementations: The instructions below feature the new NativeScript 1.1 class structure and will only work for modules created for Godot 3.1 and later. Use the following branches for older implementations:
@ -8,18 +9,22 @@ Version | Branch
**Godot 3.0 Nativescript 1.0** | [3.0](https://github.com/GodotNativeTools/godot-cpp/tree/3.0) **Godot 3.0 Nativescript 1.0** | [3.0](https://github.com/GodotNativeTools/godot-cpp/tree/3.0)
**Godot 3.1 Nativescript 1.0** | [nativescript-1.0](https://github.com/GodotNativeTools/godot-cpp/tree/nativescript-1.0) **Godot 3.1 Nativescript 1.0** | [nativescript-1.0](https://github.com/GodotNativeTools/godot-cpp/tree/nativescript-1.0)
Index: ## Table of contents
- [**Contributing**](#contributing) - [**Contributing**](#contributing)
- [**Getting Started**](#getting-started) - [**Getting Started**](#getting-started)
- [**Creating a simple class**](#creating-a-simple-class) - [**Creating a simple class**](#creating-a-simple-class)
## Contributing ## 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 the this repo.
Rémi "Akien" Verschelde wrote an excellent bit of documentation for the main Godot project on this:
https://docs.godotengine.org/en/3.0/community/contributing/pr_workflow.html
It is advisible to also install clang-format and copy the files in `misc/hooks` into `.git/hooks` so format checking is done before your changes are submitted. 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. Rémi "Akien" Verschelde wrote an excellent bit of documentation
for the main Godot project on this:
[Pull request workflow](https://docs.godotengine.org/en/3.0/community/contributing/pr_workflow.html)
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 ## Getting Started
@ -28,29 +33,36 @@ It is advisible to also install clang-format and copy the files in `misc/hooks`
### Setting up a new project ### Setting up a new project
We recommend using git for managing your project and the instructions below assume so. Alternatively you can download the source code directly from GitHub in which case you need to download both [godot-cpp](https://github.com/GodotNativeTools/godot-cpp) and [godot_headers](https://github.com/GodotNativeTools/godot_headers). We recommend using Git for managing your project. The instructions below assume
you're using Git. Alternatively, you can download the source code directly from
GitHub. In this case, you need to download both
[godot-cpp](https://github.com/GodotNativeTools/godot-cpp) and
[godot_headers](https://github.com/GodotNativeTools/godot_headers).
``` ```bash
$ mkdir SimpleLibrary mkdir SimpleLibrary
$ cd SimpleLibrary cd SimpleLibrary
$ mkdir bin mkdir bin
$ mkdir src mkdir src
$ git clone --recursive https://github.com/GodotNativeTools/godot-cpp git clone --recursive https://github.com/GodotNativeTools/godot-cpp
``` ```
Note that if you wish to use a specific branch, add the -b option to the clone command: If you wish to use a specific branch, add the -b option to the clone command:
```
$ git clone --recursive https://github.com/GodotNativeTools/godot-cpp -b 3.0 ```bash
git clone --recursive https://github.com/GodotNativeTools/godot-cpp -b 3.0
``` ```
If your project is an existing repository, use git submodule instead: If your project is an existing repository, use a Git submodule instead:
```
$ git submodule add https://github.com/GodotNativeTools/godot-cpp ```bash
$ git submodule update --init --recursive git submodule add https://github.com/GodotNativeTools/godot-cpp
git submodule update --init --recursive
``` ```
Right now our directory structure should look like this: Right now, our directory structure should look like this:
```
```text
SimpleLibrary/ SimpleLibrary/
├─godot-cpp/ ├─godot-cpp/
| └─godot_headers/ | └─godot_headers/
@ -58,46 +70,77 @@ SimpleLibrary/
└─src/ └─src/
``` ```
### Updating the api.json ### Updating the `api.json` file
Our api.json file contains meta data of all the classes that are part of the Godot core and are needed to generate the C++ binding classes for use in GDNative modules.
This file is supplied with our godot_headers repository for your convinience but if you are running a custom build of Godot and need access to classes that have recent changes a new api.json file must be generated. You do this by starting your Godot executable with the following parameters: Our `api.json` file contains metadata for all the classes that are part of the
Godot core. This metadata is required to generate the C++ binding classes for
use in GDNative modules.
``` This file is supplied with our
$ godot --gdnative-generate-json-api api.json [godot_headers](https://github.com/GodotNativeTools/godot_headers) repository
for your convenience. However, if you're running a custom build of Godot and
need access to classes that have recent changes, you must generate a new
`api.json` file. You do this by starting your Godot executable with the
following parameters:
```bash
godot --gdnative-generate-json-api api.json
``` ```
Now copy the api.json file into your folder structure so its easy to access. **Note** the remark below for the extra ```custom_api_file``` command line parameter needed to tell scons where to find your file. Now copy the `api.json` file into your folder structure to make it easier to
access.
### Compiling the cpp bindings library See the remark below for the extra ```custom_api_file``` SCons argument, which
The final step is to compile our cpp bindings library: is required to tell SCons where to find your file.
### Compiling the C++ bindings library
The final step is to compile our C++ bindings library:
```bash
cd godot-cpp
scons platform=<your platform> generate_bindings=yes
cd ..
``` ```
$ cd godot-cpp
$ scons platform=<your platform> generate_bindings=yes Replace `<your platform>` with either `windows`, `linux`, `osx` or `android`. If
$ cd .. you leave out `platform`, the target platform will automatically be detected
from the host platform.
The resulting library will be created in `godot-cpp/bin/`, take note of its name
as it'll differ depending on the target platform.
#### Compiling for Android
Download the latest [Android NDK](https://developer.android.com/ndk/downloads)
and set the NDK path.
```bash
scons platform=android generate_bindings=yes ANDROID_NDK_ROOT="/PATH-TO-ANDROID-NDK/" android_arch=<arch>
``` ```
For android:
Download the latest [Android NDK](https://developer.android.com/ndk/downloads) from the official website and set NDK path.
```
$ scons platform=android generate_bindings=yes ANDROID_NDK_ROOT="/PATH-TO-ANDROID-NDK/" android_arch=< >
```
`android_arch` can be `armv7, arm64v8, x86, x86_64`.
`ANDROID_NDK_ROOT` can also be set in the environment variables of your computer if you do not want to include it in your Scons call.
The value of `android_arch` can be `armv7, arm64v8, x86, x86_64`. Most Android
devices in use nowadays use an ARM architecture, so compiling for `armv7` and
`arm64v8` is often enough when distributing an application.
> Replace `<your platform>` with either `windows`, `linux`, `osx` or `android`. `ANDROID_NDK_ROOT` can also be set in the environment variables of your PC if
you don't want to include it in your SCons call.
> Include `use_llvm=yes` for using clang++ #### Compilation options
> Include `target=runtime` to build a runtime build (windows only at the moment) You can optionally add the following options to the SCons command line:
> The resulting library will be created in `godot-cpp/bin/`, take note of its name as it will be different depending on platform. - When targeting Linux, add `use_llvm=yes` to use Clang instead of GCC.
- When targeting Windows, add `use_mingw=yes` to use MinGW instead of MSVC.
> If you want to use an alternative api.json file add `use_custom_api_file=yes custom_api_file=../api.json`, be sure to specify the correct location of where you placed your file. - When targeting Windows, include `target=runtime` to build a runtime build.
- To use an alternative `api.json` file, add `use_custom_api_file=yes
custom_api_file=../api.json`. Be sure to specify the correct location where
you placed your file (it can be a relative or absolute path).
## Creating a simple class ## Creating a simple class
Create `init.cpp` under `SimpleLibrary/src/` and add the following code Create `init.cpp` under `SimpleLibrary/src/` and add the following code:
```cpp ```cpp
#include <Godot.hpp> #include <Godot.hpp>
#include <Reference.hpp> #include <Reference.hpp>
@ -109,7 +152,7 @@ class SimpleClass : public Reference {
public: public:
SimpleClass() { } SimpleClass() { }
/* _init must exist as it is called by Godot */ /** `_init` must exist as it is called by Godot. */
void _init() { } void _init() { }
void test_void_method() { void test_void_method() {
@ -127,15 +170,15 @@ public:
register_method("method", &SimpleClass::method); register_method("method", &SimpleClass::method);
/** /**
* How to register exports like gdscript * The line below is equivalent to the following GDScript export:
* export var _name = "SimpleClass" * export var _name = "SimpleClass"
**/ **/
register_property<SimpleClass, String>("base/name", &SimpleClass::_name, String("SimpleClass")); register_property<SimpleClass, String>("base/name", &SimpleClass::_name, String("SimpleClass"));
/* or alternatively with getter and setter methods */ /** Alternatively, with getter and setter methods: */
register_property<SimpleClass, int>("base/value", &SimpleClass::set_value, &SimpleClass::get_value, 0); register_property<SimpleClass, int>("base/value", &SimpleClass::set_value, &SimpleClass::get_value, 0);
/** For registering signal **/ /** Registering a signal: **/
// register_signal<SimpleClass>("signal_name"); // register_signal<SimpleClass>("signal_name");
// register_signal<SimpleClass>("signal_name", "string_argument", GODOT_VARIANT_TYPE_STRING) // register_signal<SimpleClass>("signal_name", "string_argument", GODOT_VARIANT_TYPE_STRING)
} }
@ -170,84 +213,131 @@ extern "C" void GDN_EXPORT godot_nativescript_init(void *handle) {
} }
``` ```
### Compiling ### Compiling the GDNative library
*Linux* Once you've compiled the GDNative C++ bindings (see above), you can compile the GDNative library we've just created.
#### Linux
```bash
cd SimpleLibrary
clang -fPIC -o src/init.os -c src/init.cpp -g -O3 -std=c++14 -Igodot-cpp/include -Igodot-cpp/include/core -Igodot-cpp/include/gen -Igodot-cpp/godot_headers
clang -o bin/libtest.so -shared src/init.os -Lgodot-cpp/bin -l<name of the godot-cpp>
``` ```
$ cd SimpleLibrary
$ clang -fPIC -o src/init.os -c src/init.cpp -g -O3 -std=c++14 -Igodot-cpp/include -Igodot-cpp/include/core -Igodot-cpp/include/gen -Igodot-cpp/godot_headers You'll need to replace `<name of the godot-cpp>` with the file that was created in [**Compiling the cpp bindings library**](#compiling-the-cpp-bindings-library).
$ clang -o bin/libtest.so -shared src/init.os -Lgodot-cpp/bin -l<name of the godot-cpp>
This creates the file `libtest.so` in your `SimpleLibrary/bin` directory.
#### Windows
```bash
cd SimpleLibrary
cl /Fosrc/init.obj /c src/init.cpp /nologo -EHsc -DNDEBUG /MDd /Igodot-cpp\include /Igodot-cpp\include\core /Igodot-cpp\include\gen /Igodot-cpp\godot_headers
link /nologo /dll /out:bin\libtest.dll /implib:bin\libsimple.lib src\init.obj godot-cpp\bin\<name of the godot-cpp>
``` ```
> This creates the file `libtest.so` in your `SimpleLibrary/bin` directory.
> You will need to replace `<name of the godot-cpp>` with the file that was created in [**Compiling the cpp bindings library**](#compiling-the-cpp-bindings-library) You'll need to replace `<name of the godot-cpp>` with the file that was created
in [**Compiling the cpp bindingslibrary**](#compiling-the-cpp-bindings-library).
Replace `/MDd` with `/MD` to create a release build, which will run faster and
be smaller.
*Windows* This creates the file `libtest.dll` in your `SimpleLibrary/bin` directory.
#### macOS
For macOS, you'll need to find out which compiler flags need to be used. These
are likely similar to Linux when using Clang, but may not be identical.
If you find suitable compiler flags for this example library, feel free to
submit a pull request :slightly_smiling_face:
#### Android
```bash
cd SimpleLibrary
aarch64-linux-android29-clang -fPIC -o src/init.os -c src/init.cpp -g -O3 -std=c++14 -Igodot-cpp/include -Igodot-cpp/include/core -Igodot-cpp/include/gen -Igodot-cpp/godot_headers
aarch64-linux-android29-clang -o bin/libtest.so -shared src/init.os -Lgodot-cpp/bin -l<name of the godot-cpp>
``` ```
$ cd SimpleLibrary
$ cl /Fosrc/init.obj /c src/init.cpp /nologo -EHsc -DNDEBUG /MDd /Igodot-cpp\include /Igodot-cpp\include\core /Igodot-cpp\include\gen /Igodot-cpp\godot_headers
$ link /nologo /dll /out:bin\libtest.dll /implib:bin\libsimple.lib src\init.obj godot-cpp\bin\<name of the godot-cpp>
```
> This creates the file `libtest.dll` in your `SimpleLibrary/bin` directory.
> You will need to replace `<name of the godot-cpp>` with the file that was created in [**Compiling the cpp bindings library**](#compiling-the-cpp-bindings-library) You'll need to replace `<name of the godot-cpp>` with the file that was created in [**Compiling the cpp bindings library**](#compiling-the-cpp-bindings-library). The command above targets `arm64v8`. To target `armv7`, use `armv7a-linux-androideabi29-clang` instead of `aarch64-linux-android29-clang`.
> Finally replace `/MDd` with `/MD` if you're generated a runtime build. This creates the file `libtest.so` in your `SimpleLibrary/bin` directory.
*macOS* #### iOS
For OSX you need to find out what compiler flags need to be used.
*Android* GDNative isn't supported on iOS yet. This is because iOS only allows linking
``` static libraries, not dynamic libraries. In theory, it would be possible to link
$ cd SimpleLibrary a GDNative library statically, but some of GDNative's convenience would be lost
$ aarch64-linux-android29-clang -fPIC -o src/init.os -c src/init.cpp -g -O3 -std=c++14 -Igodot-cpp/include -Igodot-cpp/include/core -Igodot-cpp/include/gen -Igodot-cpp/godot_headers in the process as one would have to recompile the engine on every change. See
$ aarch64-linux-android29-clang -o bin/libtest.so -shared src/init.os -Lgodot-cpp/bin -l<name of the godot-cpp> [issue #30](https://github.com/GodotNativeTools/godot_headers/issues/30) in the
``` Godot headers repository for more information.
> use `armv7a-linux-androideabi29-clang` for 32 bit armeabi-v7a library
> This creates the file `libtest.so` in your `SimpleLibrary/bin` directory. #### HTML5
> You will need to replace `<name of the godot-cpp>` with the file that was created in [**Compiling the cpp bindings library**](#compiling-the-cpp-bindings-library)
GDNative isn't supported on the HTML5 platform yet. Support is being tracked on
[issue #12243](https://github.com/godotengine/godot/issues/12243) in the main
Godot repository.
### Creating `.gdnlib` and `.gdns` files ### Creating `.gdnlib` and `.gdns` files
follow [godot_header/README.md](https://github.com/GodotNativeTools/godot_headers/blob/master/README.md#how-do-i-use-native-scripts-from-the-editor) to create the `.gdns`
### Implementing with gdscript Follow the instructions in
[godot_header/README.md](https://github.com/GodotNativeTools/godot_headers/blob/master/README.md#how-do-i-use-native-scripts-from-the-editor)
to create the `.gdns` file. This file contains paths to GDNative libraries for
various platforms. This makes the library usable from Godot in a
platform-independent manner.
### Implementing with GDScript
Once your GDNative library is compiled and referenced in a `.gdns` file, you can use it in GDScript or C#. Here's an example with GDScript:
```gdscript ```gdscript
var simpleclass = load("res://simpleclass.gdns").new(); var simpleclass = load("res://simpleclass.gdns").new();
simpleclass.method("Test argument"); simpleclass.method("Test argument");
``` ```
### Using Godot classes in C++ ### Using Godot classes in C++
Godot expects you to manage its classes the same way the engine does. These rules apply to all Godot classes, including your NativeScripts, but not to any normal C++ classes used in your library. Godot expects you to manage its classes the same way the engine does. These rules apply to all Godot classes, including your NativeScripts, but not to any normal C++ classes used in your library.
- Instantiate Objects using `_new()`, not C++'s `new` operator. - Instantiate Objects using `_new()`, not C++'s `new` operator.
```cpp ```cpp
Sprite *sprite = Sprite::_new(); Sprite *sprite = Sprite::_new();
``` ```
- Destroy Nodes using `queue_free()`, not C++'s `delete` operator. - Destroy Nodes using `queue_free()`, not C++'s `delete` operator.
```cpp ```cpp
some_old_node->queue_free(); some_old_node->queue_free();
``` ```
- Wrap References in `Ref` instead of passing around raw pointers. They are ref-counted and do not need to be freed manually.
- Wrap References in `Ref` instead of passing around raw pointers. They are reference-counted and don't need to be freed manually.
```cpp ```cpp
Ref<Texture> texture = resource_loader->load("res://icon.png"); Ref<Texture> texture = resource_loader->load("res://icon.png");
``` ```
- Pass core types that do *not* inherit Object by value. The containers (Array, Dictionary, PoolArray, String) manage their own memory and do not need to be explicitly initialized or freed. - Pass core types that do *not* inherit Object by value. The containers (Array, Dictionary, PoolArray, String) manage their own memory and do not need to be explicitly initialized or freed.
```cpp ```cpp
Array ints; Array ints;
ints.append(123); ints.append(123);
return ints; return ints;
``` ```
- Initialize your NativeScript classes in their `_init()` method, not their constructor. The constructor can't access the base class's methods. - Initialize your NativeScript classes in their `_init()` method, not their constructor. The constructor can't access the base class's methods.
- Cast objects using `Object::cast_to`, not unsafe C-style casts or `static_cast`. - Cast objects using `Object::cast_to`, not unsafe C-style casts or `static_cast`.
```cpp ```cpp
MeshInstance *m = Object::cast_to<MeshInstance>(get_node("ChildNode")); MeshInstance *m = Object::cast_to<MeshInstance>(get_node("ChildNode"));
// m will be null if it's not a MeshInstance // `m` will be null if it's not a MeshInstance
if (m) { ... } if (m) { ... }
``` ```
- Never use Godot types in static or global variables. The Godot API is not loaded until after their constructors are called.
- **Never** use Godot types in static or global variables. The Godot API isn't loaded until after their constructors are called.
```cpp ```cpp
String s; // crashes String s; // crashes
class SomeClass { class SomeClass {
@ -257,4 +347,3 @@ class SomeClass {
static Node *node_b = Node::_new(); // crashes static Node *node_b = Node::_new(); // crashes
}; };
``` ```