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FOnline Engine

Flexible cross-platform isometric game engine

FOnline Engine

Engine currently in completely unusable state due to heavy refactoring.

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Table of Content


Important note: Not all from described above features are already implemented, for additional information look at ‘Work in progress’ section below.



Repository contains source code of engine, third-party sources and build tools for composing all this stuff into final platform-specific bundles.
You may work on your game using shell scripts manually but project hosts own extension for Visual Studio Code for simplify these things.
Shell scripts targeted for work under Windows 10 within WSL2 and Ubuntu-20.04 as distro.
Almost all will be work under native Linuxes but some of scripts (like win32) must be run only from WSL2 shell because runs Windows binaries.
So main point of all of this that you build your game fully from source, there is no prebuilt binaries, full control over the process.


As described above all what you need to build and package your game in one place for different platforms is WSL2.
You may do it in separate environments (like build Windows binaries in your IDE, build macOS/iOS binaries on macOS and rest on native Linux distro) but better do it in one place.

Process of creating your game in two words looks like this:

There are couple of shell scripts that help us to do it:

Scripts can accept additional arguments ( for example accept platform for build for) and this information additionaly described in BuildTools/

Public API

Todo: write about versioning SemVer and what public API included to itself
Documents related to public API:


Clone with git this repository.
Open repository root in Visual Studio Code, install recommended extensions.
Todo: write about project generation

Windows Subsystem for Linux

Main point of WSL2 for us that we can run Windows programs from Linux.
That feature allows unify almost all our build scripts into one environment.
Recommended Linux distro is Ununtu-20.04 on which all build scripts tested.
You may use other distro but there is no guarantee that it will work out of the box.

Visual Studio Code

Engine hosts own Visual Studio Code extension for simplify work with engine stuff.
In editor go to the Extensions tab and then find and install ‘FOnline’ extension (it’s already available in marketplace).
Extension activates automatically when editor finds any file that contains fonline in name of any file at workspace root.
More about extension usage you can find in Tutorial document.

Package dependencies

Following Linux packages will help us build our game for target platforms.
These packages will automatically installed during workspace preparing (i.e.

Also our build scripts download and install following packages:

List of tools for Windows operating system (some optional):

List of tools for Mac operating system:

Other stuff used in build pipeline:

Statically linked packages

These packages included to this repository, will compile and link statically to our binaries.
They are located in ThirdParty directory.


Despite on many third-party libraries that consumed by the whole engine one of the main goal is small final footprint of client/singleplayer output.
Aim to shift most of things of loading specific image/model/sound/ect file formats at pre publishing steps and later use intermediate binary representation for loading resources in runtime as fast as possible and without additional library dependencies.
This process in terms of fonline engine called Bakering.
Also as you can see all third-party dependencies linked statically to final executable (except one - proprietary libfbxsdk.dll/so for Baker but the last one is not target for small footprint) and this frees up end user from installing additional runtime to play in your game.
Todo: write about memory footprint
Todo: write about network footprint


Please follow these instructions to understand how to use this engine by design:

Work in progress


First release version:

Futher releases:

Visual Studio Code extension

Code refactoring plans

Todo list (generated from source code)

Repository structure

Frequently Asked Questions

Following document contains some issues thats give additional information about this engine:

Help and support