flygame

Real-time Drosophila simulation with a spiking brain. C++ on MuJoCo, ~230x faster than flygym.

Quick start

cmake -G "Visual Studio 17 2022" -S cpp -B build
cmake --build build --config Release
launch.bat

WASD to walk, Space to run, Shift to fly (experimental). The brain drives motor output through descending neurons — no scripted gaits.

Packages

flygame bundles four independent packages:

flygame/
  cpp/src/         main app — viewer, brain module, proprioception
  mecha-fly/       locomotion controllers (CPG, hybrid, IK)
  mujoco-game/     MuJoCo physics wrapper + TCP protocol
  mechabrain/      spiking neural network engine (159k neurons, 6.7M synapses)

mecha-fly — Kuramoto CPG oscillator and hybrid controller (cubic spline + correction vectors). Ported from flygym's PreprogrammedSteps and HybridTurningController. Source of truth is mujoco-zoo/mecha-fly.

mujoco-game — Header-only MuJoCo wrapper. Handles the sim loop, GLFW viewer, and a simple TCP protocol (MotorCommand / SensoryReading) for remote brains.

mechabrain — Pure brain engine. Izhikevich neurons, STDP, gap junctions, homeostasis, temperature dynamics, parametric connectome generation from .brain spec files. Header-only C++23.

Controller modes

Mode	How	Description
Embedded brain	(default)	Spiking network drives motor output in-process
TCP bridge	--brain host:port	Brain runs in a separate process
Standalone CPG	build with -DNMFLY_BRAIN=OFF	WASD drives CPG directly, no brain
Flight	hold Shift	Wing oscillation with MuJoCo fluid aero (experimental)

Performance

Mode	Speed
Headless	7x realtime (~35k steps/sec)
With viewer	5.7x realtime (~29k steps/sec)
flygym (Python)	0.03x realtime

Build options

# Auto-detects MuJoCo from pip
cmake -S cpp -B build

# Specify MuJoCo location
cmake -S cpp -B build -DMUJOCO_DIR=/path/to/mujoco

# Disable brain (CPG-only mode)
cmake -S cpp -B build -DNMFLY_BRAIN=OFF

Requires C++20, CMake 3.20+, MuJoCo 3.0+. GLFW is fetched automatically.

On Windows with pip-installed MuJoCo, the build auto-generates an import library. If that fails:

cpp\cmake\gen_implib.bat "path\to\mujoco.dll" build

What's ported from flygym

flygym	flygame	Notes
PreprogrammedSteps	nmf_walk_spline.h	Periodic cubic spline (C2 smooth)
CPGNetwork	nmf_cpg.h	Same phase biases, coupling weights
HybridTurningController	nmf_hybrid.h	Magnitude + turn mapped to L/R amplitude
Retraction/stumbling corrections	NmfHybrid::UpdateCorrections()	Lifts on low foot z, retracts on swing contact
Proprioceptive obs	proprio.h	95-channel encoder (angles, velocities, contacts)

Physics parameters match flygym: timestep 0.0001s, position actuators with gainprm=45, NeuroMechFly v2 MJCF.

License

MIT. See LICENSE.

Related

• pyflygame — Python bridge and adapter framework
• flygym — Original NeuroMechFly framework (NeLy-EPFL)
• FWMC — CLI wrapper for spiking connectome experiments
• MuJoCo — Physics engine (DeepMind)