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Getting started

Install

npm install @loumalouomega/mmg-wasm

The package ships prebuilt WASM — consumers never need Emscripten, CMake or a C compiler.

Load the module

=== "ESM"

```js
import initialize from '@loumalouomega/mmg-wasm';
const mmg = await initialize();
```

=== "CommonJS"

```js
const initialize = require('@loumalouomega/mmg-wasm');
initialize().then((mmg) => { /* ... */ });
```

initialize() loads and instantiates the WASM binary and returns the API object with the three modules (mmg.mmg3d, mmg.mmg2d, mmg.mmgs), the shared constants, and mmg.FS (the in-memory filesystem).

One WASM instance, many meshes

Unlike libraries with global state, MMG is handle-based: call initialize() once and create as many independent mesh/solution pairs as you need via each module's init().

First remesh: adapt a tetrahedral cube

The canonical MMG "hello world" (upstream adaptation_example0): build a two-material cube of 12 vertices / 12 tetrahedra / 20 boundary triangles, then adapt it with a Hausdorff distance of 0.1.

import initialize from '@loumalouomega/mmg-wasm';

const mmg = await initialize();
const { mmg3d } = mmg;

// 1) allocate the MMG5_pMesh / MMG5_pSol structures
const h = mmg3d.init();

// 2) describe the input mesh
mmg3d.setMeshSize(h.mesh, 12, 12, 0, 20, 0, 0);
vertices.forEach(([x, y, z], i) => mmg3d.setVertex(h.mesh, x, y, z, 0, i + 1));
tetrahedra.forEach(([a, b, c, d, ref], i) =>
  mmg3d.setTetrahedron(h.mesh, a, b, c, d, ref, i + 1));
triangles.forEach(([a, b, c, ref], i) =>
  mmg3d.setTriangle(h.mesh, a, b, c, ref, i + 1));

// 3) optional size map (scalar metric: target edge length per vertex)
mmg3d.setSolSize(h.mesh, h.met, mmg.MMG5_Vertex, 12, mmg.MMG5_Scalar);
for (let k = 1; k <= 12; k++) mmg3d.setScalarSol(h.met, 0.5, k);

// 4) parameters and remeshing
mmg3d.setDparameter(h.mesh, h.met, mmg3d.DPARAM_hausd, 0.1);
const code = mmg3d.remesh(h.mesh, h.met);   // alias of mmg3dlib
if (code === mmg.MMG5_LOWFAILURE) console.warn('remeshed with warnings');

// 5) read the adapted mesh back
const { np, ne } = mmg3d.getMeshSize(h.mesh);
const { vertices: coords, refs } = mmg3d.getVertices(h.mesh, np);
const { tetra } = mmg3d.getTetrahedra(h.mesh, ne);

// 6) release everything
mmg3d.free(h);

Entity indices are 1-based, exactly as in the MMG C API.

Error handling

  • Set_*/Get_*/load*/save* style functions throw a JavaScript Error when MMG reports failure (C return ≠ 1).
  • The remeshing entry points (remesh, levelset, move, generate) return the MMG library code — mmg.MMG5_SUCCESS (0) or mmg.MMG5_LOWFAILURE (1) — and only throw on MMG5_STRONGFAILURE.
try {
  mmg3d.setVertex(h.mesh, 0, 0, 0, 0, 999999); // out of range -> throws
} catch (e) {
  console.error(e.message); // "MMG3D_Set_vertex failed (returned 0)"
}

Next steps