gistfile1.txt

using UnityEngine;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Globalization;
using ClipperLib;
using TriangleNet.Geometry;
using Polygon = System.Collections.Generic.List<ClipperLib.IntPoint>;
using Polygons = System.Collections.Generic.List<System.Collections.Generic.List<ClipperLib.IntPoint>>;

// alternately could use this
// https://github.com/speps/LibTessDotNet

public class PolyToMesh{
	private float multiplier = 10000;
	private Polygons subject = new Polygons();
	private Polygons clips = new Polygons();
	public void AddSubject(List<Vector2> poly){
		AddPoints (poly, subject);
	}
	public void AddClip(List<Vector2> poly){
		AddPoints (poly, clips);
	}
	void AddPoints(List<Vector2> poly, Polygons list){
		list.Add(new Polygon(poly.Count));
		foreach (Vector2 point in poly) {
			list [list.Count - 1].Add (new IntPoint (point.x * multiplier, point.y * multiplier));
		}
	}
	public Mesh GetMesh(){
		// build the clipper
		PolyTree PTsolution = new PolyTree ();
		Clipper c = new Clipper();
		c.AddPaths (subject, PolyType.ptSubject, true);
		c.AddPaths (clips, PolyType.ptClip, true);
		c.Execute (ClipType.ctDifference, PTsolution, PolyFillType.pftEvenOdd, PolyFillType.pftPositive);

		// build the triangle mesh
		// then need to convert the solution into a mesh that can be displayed
		TriangleNet.Mesh tmesh = new TriangleNet.Mesh ();

		TriangleNet.Geometry.InputGeometry input = new TriangleNet.Geometry.InputGeometry ();

		AddContourAndChildren (PTsolution, input, 0);



		tmesh.Triangulate(input);

		// convert the mesh to a unity mesh
		Vector2[] uv;
		Color32[] cs;
		Vector3[] vertices;
		Vector3[] normals;

		Mesh mesh = new Mesh();
		mesh.name = "Display mesh";
		mesh.hideFlags = HideFlags.HideAndDontSave;
		vertices = new Vector3[tmesh.Vertices.Count()];
		normals = new Vector3[vertices.Count()];

		uv = new Vector2[tmesh.Vertices.Count()];
		TriangleNet.Data.Vertex[] tVertices = tmesh.Vertices.ToArray ();
		int[] tri = new int[tmesh.Triangles.Count()*3];
		Debug.Log (vertices.Count());
		Debug.Log (normals.Count());

		for(int i=0;i<vertices.Count();i++){
			vertices[i] = new Vector3((float)tVertices[i].X, (float)tVertices[i].Y, 0);
			uv[i] = new Vector2((float)tVertices[i].X, (float)tVertices[i].Y);
			normals [i] = (new Vector3(0,1,1)).normalized;
		}
		for(int i=0;i<tmesh.Triangles.Count();i++){
			tri[0+i*3] = tmesh.Triangles.ElementAt(i).P0;
			tri[2+i*3] = tmesh.Triangles.ElementAt(i).P1;
			tri[1+i*3] = tmesh.Triangles.ElementAt(i).P2;
		}
		mesh.vertices = vertices;
		normals = mesh.normals;
		mesh.triangles = tri;
		mesh.uv = uv;
		return mesh;
	}
	int AddContourAndChildren(PolyNode pt, InputGeometry ig, int EdgeMarker){
		int startIndexMark = ig.Count;
		int indexMarker = startIndexMark;
		if (pt.Contour.Count > 0) {
			float avgX = 0;
			float avgY = 0;
			foreach (ClipperLib.IntPoint p in pt.Contour) {
				int nextMarker = ((indexMarker - startIndexMark + 1) % pt.Contour.Count + startIndexMark);
				ig.AddPoint ((float)p.X/multiplier, (float)p.Y/multiplier, EdgeMarker-1);
				ig.AddSegment (indexMarker, ((indexMarker-startIndexMark + 1)%pt.Contour.Count+startIndexMark), EdgeMarker-1);
				avgX += p.X;
				avgY += p.Y;
				indexMarker++;

			}
			if (pt.IsHole) {
				// this method won't work for adding concave polygons
				ig.AddHole (avgX / (indexMarker+1 - startIndexMark)/100f, avgY / (indexMarker+1 - startIndexMark)/100f);
			}
		}
		foreach (PolyNode ptc in pt.Childs) {
			EdgeMarker++;
			EdgeMarker = AddContourAndChildren (ptc, ig, EdgeMarker);
		}
		return EdgeMarker;
	}
}

line 102: replace "/100f" with "/multiplier"