Source Module Layout¶

Here is the project’s dependency graph:

The top level of this project hosts the primary Haskell modules.
The embedded submodules simula-wayland, simula-osvr, and simula-openvr contain FFI bindings (via c2hs) that connect to their respective C libraries shown above.
In order to run the vive-compositor, you will need nvidia-381.26.13 or greater installed on your system, which (unfortunately) nix cannot provide. You do not need nvidia drivers, however, to run the simulavr.
A list of technologies in use: Haskell, C/C++ (c2hs, inline-c), OpenGL, wayland & weston, OSVR, OpenVR, nix (for build dependencies).

Development Status¶

Goal	Status	Short-Run Horizon	Long-Run Horizon
Basic, Launchable Compositor	DONE	X
Wayland App Compatibility	DONE	X
X Applications Compatibility		X
HTC Vive Compatibility		X
Usable VR Desktop		X
Test Suite		X
Clear Text Resolution in VR			X
Special-Purpose 3D Linux Apps			X
A “VR Linux Distro”			X
Standalone HMD Compatibility			X

This is a compilation of old TODO notes. Important items from this list should moved to Issues.

Awful C++-esque typeclass structure. In most cases, Some a can be replaced with something better. However due to time/etc limitations, the current code architecture closely mirrors the simula_cpp one.
hs-boot files due to the above. Annoying extra bookkeeping and should be phased out whenever possible.
General stinginess with comments. In case something is unclear, chances are it’s either unclear in the motorcar source and/or unclear to me (since it was ported from motorcar/simula_cpp). Ask anyways though.
MVars are used whenever mutable state is required. This is not always needed, and I’ve attempted to reduce the amount of mutable references, but it’s likely I missed some.

.Event is basically unused. Weston handles all of that stuff.
Geometry is mostly clean, apart from Rectangle being a misnomer (Rect is the actual Rectangle)
OpenGL contains viewport code (relatively straightforward) and shader code (slightly suboptimal, as it compiled shaders too often; they should be cached)
checkForErrors terminates the program on an OpenGL error with a backtrace; this can be deactivated by commentiong out the error line
The scene graph is a big unholy mess of C++-esque code. It needs a massive refactoring.
Gratitious use of RecursiveDo (aka mfix) to deal with (x needs reference of y, and vice versa, to be constructed) and superclass stuff. Could be solved by refactoring the above C++ mess.
Generally, resources need to be cleaned up better. Consider ResourceT.
The Weston surfaces currently don’t have a type. This should be fixed.
Weston.hs in general is a bit messy, and could use some cleaning up.
The OSVR branch Weston.hs has modifications in the render loop and a reference to OSVR.hs’ SimulaOSVRCLient. It should be merged back into the main branch.