FLAW :: Engine

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FLAW is a highly experimental open source game engine written in Haskell.


FLAW is heavily based on my experiences from developing Inanity engine. In short, the experiences are: C++ sucks, game development can be done better. It's time to discover new horizons by using Haskell in the area where it hasn't been used a lot (yet).

This project is mostly a playground for absolutely crazy ideas. Surely if someone managed to make a real game out of it, that game would be absolutely crazy too!


FLAW uses stack for building. Note the assumption is that the project is to be built with integer-simple GHC, to be more commercial-friendly due to concerns about LGPL license of GMP library used by stock GHC (especially on Windows where GHC does not support dynamic linking of GMP). See stack.yaml, which refers to integer-simple-snapshot.yaml containing appropriate adjustments to some packages. If you don't have integer-simple GHC, or don't care about GMP, simply set resolver field in stack.yaml to desired snapshot directly and remove ghc-variant: integersimple.


Some binaries (built from CI) are available on FLAW itch.io page.

What works

In progress



Packages and platform support

Linux is the primary development platform. It also considered the only "server" platform, hence several "server" packages are tested only on Linux, although it's probably possible to compile and run them on Windows or macOS.

Here are all packages in A-Z order. Checkmark against a platform means that the package is being actually built and tested (if it has tests :D) on this platform during CI.

Package Description Linux Windows macOS Web (GHCJS)
flaw-al OpenAL integration - implementation of flaw-audio interface
flaw-app Handy engine initialization and main loop routines
flaw-asset Packing and unpacking assets into asset packs
flaw-asset-dxt DXT image compression based on fork of libsquish library
flaw-asset-wai Asset distribution for web games with perfect caching
flaw-audio General interface for audio device
flaw-base Base primitives (resource management, concurrency, etc)
flaw-build Embedding data into executable
flaw-bullet Initial integration with Bullet Physics engine
flaw-canvas Very simple 2D drawing
flaw-collada Importing Collada assets
flaw-dx11 DirectX 11 integration - implementation of flaw-graphics interface
flaw-editor Visual asset editor (WIP)
flaw-ffi Interoperation with native code
flaw-ffmpeg Experimental bindings to ffmpeg
flaw-font General interface for font rendering
flaw-font-fhi Implementation of flaw-font interface using FreeType + Harfbuzz + ICU
flaw-font-icu Separate ICU package
flaw-game Non-finished experimental stuff about game synchronization
flaw-gamejolt-webapi GameJolt Web API
flaw-gl OpenGL integration - implementation of flaw-graphics interface
flaw-gl-mesa Experimental MESA integration for offscreen software rendering
flaw-gl-sdl OpenGL-to-windowing binding via SDL
flaw-gl-win32 OpenGL-to-windowing binding via Win32 API
flaw-graphics General interface for graphics
flaw-input General user input interface
flaw-itch-webapi Itch.io Web API
flaw-js Some generic javascript routines
flaw-lmdb LMDB binding
flaw-lua Experimental Lua-to-Haskell translator
flaw-lua-refimpl Lua reference implementation from lua.org
flaw-math Math library
flaw-math-determ Deterministic math library
flaw-network Some network socket implementations (WIP)
flaw-oil Reimplementation of Oil protocol
flaw-oil-client Simple command-line client for Oil protocol
flaw-oil-server Server for Oil protocol
flaw-physics General interface for physics simulation
flaw-script Scripting in Haskell
flaw-sdl Integration with SDL 2
flaw-sl Generic shader languages helping code
flaw-social Some social network integration
flaw-sqlite SQLite binding
flaw-steam General definitions for Steam API
flaw-steam-encryptedticket Steam encrypted ticket library bindings
flaw-steam-webapi Steam Web API
flaw-ui UI library using flaw-graphics for rendering
flaw-ui-default-style Hardcoded "default" UI styles
flaw-visual High-level rendering techniques
flaw-vulkan Vulkan integration - implementation of flaw-graphics interface
flaw-websocket-client Websocket client library
flaw-websocket-server Websocket server library
flaw-window Windowing platform bindings and graphics support