Brain

src/brain.ts is the bridge between Three.js and the WASM World. It owns the World instance, builds the geometry bound to WASM memory, and exposes a small API the rest of the app uses.

Construction

createBrain(assets, renderer, backend) initializes the WASM module and builds a Brain. The constructor imports the generated module and the wasm binary URL:

src/brain.ts

import init, { World } from '../rust/brain_sim/pkg/brain_sim'
import wasmUrl from '../rust/brain_sim/pkg/brain_sim_bg.wasm?url'

It mirrors the WASM-side defaults into a JS-side settings object and reads the live style fields (colors, sizes, opacity) from the World getters, then builds three things:

• a ParticlePoolBridge for the moving signals,
• the neuron Points geometry,
• the axon LineSegments geometry.

All three bind their buffers to WASM memory via typed-array views.

Per-frame update

src/brain.ts

update(deltaTime: number): void {
  this.refreshIfMemoryGrew()
  this.world.step_cpu(deltaTime)
  this.particlePool.update()
}

refreshIfMemoryGrew() rebinds views if WASM memory grew (see Overview), step_cpu advances the simulation and writes positions, and the particle pool flags its attribute for upload.

Public API

Member	Purpose
update(dt)	Advance one frame.
injectStimulus(opts)	Forward { type, intensity, durationMs } to World::inject_stimulus.
getTelemetrySnapshot()	Return the typed TelemetrySnapshot.
updateSettings()	Push all settings, colors, and material uniforms into the World.
numNeurons / numAxons / numSignals	Live counts (getters).
travelBackend	Always 'cpu' in the current build.
meshComponents	The Object3D added to the scene.

Settings round-trip

updateSettings() writes every setting and color into the World and also updates the material uniforms and the neuron color buffer:

src/brain.ts

this.world.set_setting('currentMaxSignals', this.settings.currentMaxSignals)
this.world.set_setting('signalMinSpeed', this.settings.signalMinSpeed)
this.world.set_setting('signalMaxSpeed', this.settings.signalMaxSpeed)
this.world.set_setting('neuronSizeMultiplier', this.neuronSizeMultiplier)
this.world.set_setting('neuronOpacity', this.neuronOpacity)
this.world.set_setting('axonOpacityMultiplier', this.axonOpacityMultiplier)
this.world.set_color('neuronColor', hexStringToInt(this.neuronColor))
this.world.set_color('axonColor', hexStringToInt(this.axonColor))

This is the function every GUI control calls through onChange. See UI Guide.

ParticlePoolBridge

A class inside brain.ts that manages the signal Points. Its position attribute views the WASM-owned particle buffer that step_cpu writes each frame. It re-checks wasm.memory.buffer every frame and rewraps its view when the buffer changes, then flags needsUpdate so the GPU upload happens. It also holds the pColor and pSize controls used by the GUI.