memononen/tess2.js

GLU tesselator ported to Javascript, performs polygon boolean operations and triangulation.

tess2.js

The tess2.js library performs polygon boolean operations and tesselation to triangles and convex polygons. It is a port of libtess2, which is turn is a cleaned up version of the stock GLU tesselator. The original code was written Eric Veach in 1994. The greatest thing about tess2.js is that it handles all kinds of input like self-intersecting polygons or any nomber of holes and contours.

Installation: npm install tess2 --save

Example use:

var Tess2 = require('tess2');

// Define input
var ca = [0,0, 10,0, 5,10];
var cb = [0,2, 10,2, 10,6, 0,6];
var contours = [ca,cb];

// Tesselate
var res = Tess2.tesselate({
	contours: contours,
	windingRule: Tess2.WINDING_ODD,
	elementType: Tess2.POLYGONS,
	polySize: 3,
	vertexSize: 2
});

// Use vertices
for (var i = 0; i < res.vertices.length; i += 2) {
	drawVertex(res.vertices[i], res.vertices[i+1]);
}
// Use triangles
for (var i = 0; i < res.elements.length; i += 3) {
	var a = res.elements[i], b = res.elements[i+1], c = res.elements[i+2];
	drawTriangle(res.vertices[a*2], res.vertices[a*2+1],
		res.vertices[b*2], res.vertices[b*2+1],
		res.vertices[c*2], res.vertices[c*2+1]);
}

Further reading: http://www.glprogramming.com/red/chapter11.html

Browser / AMD / etc

The build/tess2.js works with RequireJS, CommonJS, or "no-module" patterns, like a simple script tag:

<script src="tess2.js"></script>
<script>
var res = Tess2.tesselate({ ... });

//same as above...
</script>

Building

To build the UMD file, enter the following:

npm run build

tess2.js's Issues

Publishing on NPM?

Any plans to publish this on NPM? It seems like a great tool.

"TRUE"? What does that mean?

"TRUE"? What does that mean?

Only module for polygon boolean functions.

I have requirement only for polygon boolean functions. So do you have separate module for the same not including tesselation related function.
Or tesselation is must for calculating the polygon boolean functions?
I want to use this lib on client side (browser) so separate module would be lighter.