GDevelop.js

These are the bindings of GDevelop core classes to WebAssembly+JavaScript. This allows GDevelop Core libraries to run in a browser or on Node.js.

How to build

👋 Usually, if you're working on the GDevelop editor or extensions in JavaScript, you don't need to rebuild GDevelop.js. If you want to make changes in C++ extensions or classes, read this section.

Prerequisite tools installed:
- CMake 3.17+ (3.5+ should work on Linux/macOS). On macOS, you can install it via Homebrew (recommended for Apple M1 Architectures).
- Node.js. (We recommend using nvm to be able to switch between Node versions easily).
- Python (via pyenv for versions management).

Install Emscripten version 3.1.21, as explained below or on the Emscripten installation instructions:

git clone https://github.com/emscripten-core/emsdk/
cd emsdk
git pull
./emsdk install 3.1.21
./emsdk activate 3.1.21

# On Windows, also install an additional Python package:
pip install setuptools

Whenever you try to build GDevelop.js in the future, you will have to load the emsdk environement into your terminal window again by running:

Linux/macOS Windows (Powershell) Windows (cmd.exe)

source ./emsdk_env.sh ./emsdk_env.ps1 ./emsdk_env.bat
With the emscripten environement loaded into your terminal, launch the build from GDevelop.js folder:
```
cd GDevelop.js
npm install # Only the first time.
npm run build # After any C++ changes.
```
⏱ The linking (last step) of the build can be made a few seconds faster, useful for development: npm run build -- --variant=dev.
You can then launch GDevelop 5 that will use your build of GDevelop.js:
```
cd ..
cd newIDE/app
npm install
npm start
```

More information in GDevelop 5 README.

Tests

npm test

Debugging

You can build the library with various level of debugging and memory checks.

npm run build -- --variant=debug # Build with debugging information (useful for stacktraces)
npm run build -- --variant=debug-assertions # Build with assertions and "SAFE_HEAP=1", useful to find memory bugs.
npm run build -- --variant=debug-sanitizers # Build with memory sanitizers. Will be very slow.

It's then recommended to run the tests (npm test) to check if there are any obvious memory bugs found.

About the internal steps of compilation

The npm build task:

Creates Binaries/embuild directory,
Launches CMake inside to compile GDevelop with emconfigure to use Emscripten toolchain,
Updates the glue.cpp and glue.js from Bindings.idl using Emscripten WebIDL Binder,
Launches the compilation with make (or ninja on Windows with CMake 3.17+) (you can also compile using MinGW-32 using npm run build-with-MinGW).

See the CMakeLists.txt for the arguments passed to the Emscripten linker. For instance, if you want to see the function names in stacks or for profiling, the compilation flags can be changed.

Documentation

The file Bindings.idl describes all the classes available in GDevelop.js.
Refer to GDevelop documentation for detailed documentation of the original C++ classes.