About

The Greenfield SDK allows for native Wayland applications to be compiled to WebAssembly. The SDK is based on Emscripten and adds support for Wayland and blocking poll/epoll.

Installation

Clone the repository if you haven’t already.

git clone https://github.com/udevbe/greenfield.git

The SDK is located inside directory sdk. To use the SDK, we first need to build it.

Make sure all required Greenfield packages are installed. These are listed in Greenfield Getting Started

./build.sh

This will build a sysroot with number of commonly used graphics libraries. If all went well there should be 3 additional directories. build-sysroot has native binaries that are required to build and use the Greenfield SDK. emsdk is the Emscripten SDK which the Greenfield SDK uses. sysroot is a cross-compilation sysroot which contains the libraries we just build.

You only need to build the SDK once.

Usage

Add the SDK binaries to the PATH of your current running shell.

source sdk_env.sh

This makes following programs available. Arguments for each of these are the same as in Emscripten, except for wayland-scanner.

gf++
gf_file_packager
gfar
gfcc
gfnm
gfranlib
wayland-scanner

There are also two Meson --cross-file available. These need to be specified in-order when using Meson.

--cross-file "$SDK_DIR/toolkit/meson-gf-cross.ini" --cross-file "$SDK_DIR/toolkit/meson-gf-toolchain.ini"

More examples are available in examples/sdk.

Limitations

Emscripten

The Greenfield SDK is an extension of the Emscripten SDK. Emscripten is a web POSIX compatibility layer, but is not Linux compatibility layer. This can be problematic as Wayland applications are by definition Linux applications. These Linux applications can depend on much more functionality than what is provided by Emscripten.

A possible solution is to compile the Linux kernel to WASM and run it directly in the browser. This allows for a userland stack that is completely compatible with Linux system calls which greatly improves the compatibility of LinuxWayland WASM applications.

File System

File system support is currently limited to what is supported by Emscripten until a shared file system is implemented.