threejs-procedural-materials

Procedural Materials

Build a cause graph, not a collection of channel effects:

stable coordinates -> structural causes -> identity weights
  -> causal modifiers -> filtered microstructure
  -> NodeMaterial PBR slots -> final-image owner

Use MeshStandardNodeMaterial for standard opaque/emissive PBR and MeshPhysicalNodeMaterial only when its extra lobes or transport properties are part of the surface. Keep Three.js lighting, environment, shadows, and energy handling by assigning node slots instead of replacing the whole fragment output.

For multi-system scenes, $threejs-choose-skills is an optional coordinator. Fields own shared scalar/vector causes, geometry owns silhouettes, water owns surface/transport, and the final-image pipeline owns tone mapping and display conversion. Consume each dynamic or cross-system cause with declared units, coordinate/frame convention, producer and consumer owners, revision, spatial/temporal support and filter, validity domain, error bound, update cadence, and staleness rule. A visual material state does not become another simulation owner.

Initialize and gate the renderer before allocating storage, dispatching compute-written cause maps, or compiling storage-backed material branches:

await renderer.init();
if (renderer.backend.isWebGPUBackend !== true) {
  throw new Error('Native WebGPU is required for procedural material GPU branches.');
}
const { features, limits } = renderer.backend.device;

Select sampled/storage bindings, writable formats, and filtering from those initialized features and limits.

1. Freeze coordinates, causes, and identities

Choose UV, object, world, radial, or generated-texture space from the physical or authored cause. Record scale in meters or declared art units. Mixing spaces is valid only for distinct causes, such as world-height wetness over object-space grain.

Define normalized material identity weights and a response bundle per identity:

linear base reflectance
roughness alpha and metal/dielectric endpoint
resolved height/normal spectrum plus removed variance
causal modifiers such as wetness, wear, heat, or coverage
semantic/material ID and diagnostic color