Procedural field contract · CPU + TSL + optional TypeGPU

The field you draw is the field you can touch.

Let CPU collision, buoyancy, forces, and hit tests query procedural fields that Three.js materializes on the GPU—then measure the remaining float drift instead of asserting equality.

Read the contract

MIT
zero-dependency core
cross-runtime CI
public preview

Live 3D terrain instrument / dunesField sampling…

Drift contrast shows the absolute f64 ↔ f32 difference. Color is normalized to this sampled map and square-root stretched so tiny differences are visible; the readout remains the actual difference in field units.

CPU / f64: —
Assay / f32: —
Absolute drift: —

The split-world problem

GPU 3D displacement is invisible to CPU gameplay.

CPU physics, AI, servers, and hit tests cannot sample the vertex shader shaping a 3D world. Copying procedural math into JavaScript and shader code creates two authorities that can drift.

Matter Field makes the pure function authoritative and treats each native adapter backend as a materialization of it. The optional TypeGPU lane is a separately assayed port.

Field contract

Write the field, not its copies.

terrain.jsone field

export function terrain(A, x, z) {
  const n = fbm(A, x, z, 0.0016, 2);
  return A.mul(
    A.sub(n, A.f(0.5)),
    A.f(24)
  );
}

F64

numberAdapter

CPU oracle

Collision, AI, Workers, and Node servers evaluate the authoritative ECMAScript f64 tree.

TSL

makeTslAdapter

Native GPU graph

The zero-dependency core accepts the caller’s three/tsl namespace and preserves one adapter-authored tree.

∂

dualAdapter

Analytic gradients

Dual numbers derive normals and tangents from the exact same expression tree.

TGPU

matter-field/typegpu

TypeGPU materialization

An optional, separately authored WebGPU port is precompiled for TypeGPU and @typegpu/three, then checked against the canonical fields.

Live field index

Where the contract has consequences.

Choose a focused field, inspect the live assay, or follow the production lineage. Each entry names the CPU consumer instead of hiding the work behind a shader.

Terrain contact

Dunes

Drive over GPU-displaced terrain while four CPU contact probes sample the authoritative field.

Open field Four-point buoyancy

Swell

Pilot a hull whose heave, pitch, and roll come from the same field shaping the GPU water.

Open field Vector force

Wind

Fly through a visible flow volume while the CPU samples that vector field as a gameplay force.

Open field Moving-volume query

Serpent

Orbit an animated procedural body while CPU world rays query its authored spine and radius.

Open field Hardware evidence

Parity assay

Run the TSL field graphs on this browser’s WebGPU or WebGL2 backend and download a device-scoped receipt.

Run assay Production lineage

OBJEKT-62

The game where the shared terrain-adapter pattern was pressure-tested before being generalized into Matter Field.

Visit project

Measured, not asserted

Current hardware receipts

Absolute error in field units decides pass/fail. ULP counts remain diagnostic because they explode near zero crossings.

Recorded parity results by graphics hardware and browser backend
Hardware	Backend	Max observed abs	Max ULP	u32 hash	Status

The honest contract

Three contract levels, no stronger.

Tier 1
CPU ↔ CPU
tested bit-exact
One committed golden agrees in browser, Worker, and supported Node CI.
Tier 2
Integer hash
observed bit-exact
Eleven raw u32 vectors agree in the current hardware receipts.
Tier 3
Float tree
measured per field
Restricted f32 operations tested against a declared absolute field-unit budget on each receipt.

Open measurement

Bring a GPU.
Add a receipt.

The parity claim gets stronger through public measurement, not louder marketing. Run the assay, inspect the JSON, and contribute a missing vendor cell.

Run on this hardware