delatin

delatin

A fast JavaScript 3D terrain mesh generation tool. Approximates a height field with a Delaunay triangulation, minimizing the amount of points and triangles for a given maximum error.

Delatin is a port of Michael Fogleman's hmm (C++), which is in turn based on the paper Fast Polygonal Approximation of Terrains and Height Fields (1995) by Michael Garland and Paul Heckbert.

Live Demo

Example

const tin = new Delatin(heightValues, width, height);

tin.run(0.3); // run mesh refinement until max error is less than 0.3
const {coords, triangles} = tin; // get vertices and triangles of the mesh

API

new Delatin(heightValues, width, height)

Creates a new Delatin instance given a height field in the form of a flat array of numbers (with width * height length).

tin.run(maxError = 1)

Performs mesh refinement until maximum error reaches below the given maxError. You can do this multiple times with successively smaller maxError.

tin.refine()

Runs a single iteration of mesh refinement, adding a single point to the mesh. Useful when generating the mesh with custom stop conditions (e.g. maximum number of points or triangles).

tin.getMaxError()

Returns the current maximum error of the mesh, defined by the maximum vertical distance between a point in the original height field and its triangular approximation.

tin.getRMSD()

Returns the current root-mean-square deviation of the mesh.

tin.heightAt(x, y)

Returns the height value at a given position, with x, y being integer coordinates that reference the original height field.

tin.coords

After running mesh refinement, this will be an array of x, y vertex coordinates of the final mesh (note: without z, but you can use tin.heightAt(x, y) to get the height for each vertex).

tin.triangles

After running mesh refinement, this will be an an array of triangle indices of the final mesh. Each triple of numbers defines a triangle and references vertices in the tin.coords array.

Install

Run npm install delatin or yarn add delatin. Delatin is exposed as a ES module, so you can use it like this in modern browsers:

<script type="module">
import Delatin from 'https://unpkg.com/delatin';

To use ES modules in Node, either use esm (node -r esm app.js), or node --experimental-modules app.js for Node v12+.