Materials

EXEPERT uses two custom ShaderMaterials, both classic GLSL ES (not TSL), living in src/materials/. They are the same shaders that drive the legacy reference pages, which is why they are referred to as the "v1" shaders.

Neuron material

src/materials/neuron.ts renders the neuron Points. The vertex shader sizes each point by its per-vertex size attribute, a global sizeMultiplier uniform, and distance attenuation:

src/materials/neuron.ts (vertex)

gl_PointSize = size * sizeMultiplier * (300.0 / length(mvPosition.xyz));

The fragment shader multiplies the per-vertex color and opacity by the sprite texture:

src/materials/neuron.ts (fragment)

gl_FragColor = vec4(vColor, opacity) * texture2D(map, gl_PointCoord);

The material uses AdditiveBlending, transparent: true, and depthTest: false, which gives the glowing, layered look.

Uniform naming

The texture uniform is named map, not texture, to avoid a GLSL ES 3.00 reserved-word collision. This is the one deliberate difference from the original v1 shaders.

The factory returns a bundle with setters so the GUI can mutate uniforms without rebuilding the material:

src/materials/neuron.ts

export interface NeuronMaterialBundle {
  material: ShaderMaterial
  setSizeMultiplier(value: number): void
  setOpacity(value: number): void
}

Axon material

src/materials/axon.ts renders the axon LineSegments. It applies the per-vertex opacity attribute times a global opacity multiplier, with additive blending, so denser bundles of axons read as brighter. Its bundle exposes setColor and setOpacityMultiplier, which Brain.updateSettings() calls when the corresponding GUI controls change.

How they connect to the GUI

Brain.updateSettings() updates these material uniforms alongside the WASM settings:

src/brain.ts

this.neuronMaterial.setOpacity(this.neuronOpacity)
this.neuronMaterial.setSizeMultiplier(this.neuronSizeMultiplier)
this.axonMaterial.setColor(this.axonColor)
this.axonMaterial.setOpacityMultiplier(this.axonOpacityMultiplier)

So changing "Neuron Opacity" or "Axon Opacity Mult" in the panel updates both the simulation-side value and the shader uniform in the same call.