Godot is a full 2D and 3D game engine with editor.

wget https://github.com/godotengine/godot/releases/download/4.0.4-stable/godot-4.0.4-stable.tar.xz
tar xf godot-4.0.4-stable.tar.xz
cd godot-4.0.4-stable/platform/
git clone https://github.com/Cebion/frt.git
cd ../
scons target=template_release frt_std=c++17 optimize=speed debug_symbols=no platform=frt use_llvm=yes -j8

wget https://github.com/godotengine/godot/releases/download/4.1.3-stable/godot-4.1.3-stable.tar.xz
tar xf godot-4.1.3-stable.tar.xz
cd godot-4.1.3-stable/platform/
git clone https://github.com/Cebion/frt.git
cd ../
scons target=template_release frt_std=c++17 optimize=speed debug_symbols=no platform=frt use_llvm=yes vulkan=false openxr=false use_volk=false arch=arm64 -j10

FRT is a Godot "platform" targeting single board computers. In plain English, you can export a Godot game to most of them by using FRT binaries, as long as the game has been designed with the limitation of the hardware in mind.

Godot comes with a generic X11 platform that works very well on most modern single board computer. So, if you are using X11, it is probably better to compile the official engine for ARM and use that.

If your distro uses something other than X11, you can try if FRT works for you. KMS/DRM and FBDEV are common display technologies, but Wayland is also slowly becoming more popular.

First, you need to export a game from the official Godot editor. The platform where you run the editor doesn't matter.

One option is to use precompiled binaries from here:

https://sourceforge.net/projects/frt/files/

as custom templates. Another option is to export a .PCK file and use the FRT binary to run it. Details vary, but the end result is usually a script with a command that looks something like this:

./frt_200_342_arm64v8.bin --main-pack MyGame.pck

There are some guides and posts around describing the process for FRT 1.0. The process is pretty much the same for FRT 2.0.

FRT binary releases follow the following naming convention:

frt_frt-version_godot-version_arch-tag.bin

For example:

frt_200_342_arm32v7.bin

is FRT 2.0.0 compiled against Godot 3.4.2-stable. It is compiled for a 32-bit distro. While:

frt_200_342_arm64v8.bin

is compiled for a 64-bit distro. The arm32v6 ones are there mainly to support older Pis.

My policy is to publish binaries for the latest release from upstream plus 2.1.6 and the ones that were/are in debian stable (currenty 3.0.6 and 3.2.3). You are encouraged to compile any version you need yourself. See Compile for more info.

Ideally the codebase should be able to support building against any upstream stable version since 2.1.6, but this is rarely tested.

Starting from version 2.0, FRT uses and dynamically links the SDL2 library, so you can leverage a custom version of SDL2 patched for your board and distro.

Keep in mind that SDL2 is a fairly complex library, and you can customize its behaviour using environment variables. Before looking for alternatives to the version of SDL2 already installed, it is probably worth spending some time testing different drivers and options.

In my (limited) experience, an exception is older Pis (the ones best used with legacy drivers), where the SDL that you get out of the box is not that great.

This would also serve as an example of how to use a custom SDL library.

Download a binary archive from here:

https://github.com/efornara/sdl2/releases

uncompress it somewhere, and run the FRT binary like this:

export LD_LIBRARY_PATH=~/local/sdl/linux-arm32v6
./frt_200_216_arm32v6.bin -path ~/games/mygame