simulation

A GPU-accelerated neuroevolution sandbox. Watch populations of creatures grow brains from scratch, learn to forage, avoid poison, dodge predators, and talk to each other — all in real time.

Features

• Evolved neural-net brains — every creature is wired by a graph network that mutates and crossovers across generations (weight/bias jitter, AddEdge, AddNeuron, RemoveEdge, RemoveNeuron at equal odds)
• GPU compute pipeline — sensor pass and brain forward pass run on wgpu compute shaders, scaling to thousands of creatures per tick
• 52 sensory inputs — hunger, health, age, heading, oscillator, proprioception, 4-sector vision for food/poison/obstacles/creatures, terrain elevation/speed/cost/hazard (local + 4-sector lookahead), food & poison odor/color, and 4-sector voice signal
• 10 motor outputs — thrust, turn-left, turn-right, speed, mate, eat, attack, memory, speak (gated), voice (evolved scalar message)
• Creature-to-creature voice channel — speak action gates an evolved scalar onto nearby listeners; speakers spend energy, listeners gain a small bonus, mates that both speak get a reproduction synergy
• Procedural terrain — seeded heightfield with per-tile speed multiplier, energy cost, and hazard damage
• Live config — every simulation knob (energy budgets, mutation rate/amount, food/poison spawn rates, signal cost, mate threshold, max births/tick, etc.) is editable on the fly via egui sidebar
• Creature inspector — click any creature to see its full neural graph in a separate window, color-coded by node type and weighted edge magnitude
• Save/load — persist whole simulations or just the top-N% oldest creatures to seed future runs
• Debug overlays — signal halos, FOV cones, terrain visualization, all toggleable
• Stats panel — live population, births/deaths, survival rate, food/poison counts, food eaten, generation counter

Configuration

All simulation parameters are live-editable through the egui sidebar at runtime — no config file needed for normal operation.

For seed/initial values, edit config.json at the project root, or the SimulationConfig defaults in sim/src/sim/resources.rs.

The brain I/O layout (input and output nodes) is defined in sim/src/main.rs — add or remove nodes here to extend the sensorium or action set.

Building

Requires a Vulkan/DX12/Metal-capable GPU and Rust stable.

cargo build --release
cargo run --release

For benchmarks of the GPU sensor + brain pipeline:

cargo bench -p sim

Workspace layout

• engine/ — neural-net core: NeuralGraph, mutation/reproduction primitives, activations, generic Net forward pass
• sim/ — Bevy app, GPU compute pipelines (brain_compute.wgsl, sensor_compute.wgsl), simulation loop, world rendering, egui UI
• macros/ — derive macros for neuron metadata

Controls

• Middle-click drag — pan camera
• Scroll wheel — zoom
• Left-click creature — select & inspect brain
• Sidebar sliders — tune parameters live; changes apply on next tick

Tech stack

• bevy — ECS / windowing
• wgpu — compute shaders for sensors and brain forward pass
• bevy_egui — runtime config UI and inspector
• bevy_vector_shapes — 2D shape rendering

Screenshots