CentralizedControl/Veldrid.Common/Poly2Tri/Triangulation/Util/PolygonGenerator.cs

/* Poly2Tri
 * Copyright (c) 2009-2010, Poly2Tri Contributors
 * http://code.google.com/p/poly2tri/
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * * Neither the name of Poly2Tri nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using Veldrid.Common.Poly2Tri.Polygons;

namespace Veldrid.Common.Poly2Tri.Triangulation.Util
{
	public class PolygonGenerator {
		static readonly Random RNG = new Random();

		private static double PI_2 = 2.0 * Math.PI;

		public static Polygon RandomCircleSweep(double scale, int vertexCount) {
			PolygonPoint point;
			PolygonPoint[] points;
			double radius = scale / 4;

			points = new PolygonPoint[vertexCount];
			for (int i = 0; i < vertexCount; i++) {
				do {
					if (i % 250 == 0) {
						radius += scale / 2 * (0.5 - RNG.NextDouble());
					} else if (i % 50 == 0) {
						radius += scale / 5 * (0.5 - RNG.NextDouble());
					} else {
						radius += 25 * scale / vertexCount * (0.5 - RNG.NextDouble());
					}
					radius = radius > scale / 2 ? scale / 2 : radius;
					radius = radius < scale / 10 ? scale / 10 : radius;
				} while (radius < scale / 10 || radius > scale / 2);
				point = new PolygonPoint(radius * Math.Cos((PI_2 * i) / vertexCount),
										  radius * Math.Sin((PI_2 * i) / vertexCount));
				points[i] = point;
			}
			return new Polygon(points);
		}

		public static Polygon RandomCircleSweep2(double scale, int vertexCount) {
			PolygonPoint point;
			PolygonPoint[] points;
			double radius = scale / 4;

			points = new PolygonPoint[vertexCount];
			for (int i = 0; i < vertexCount; i++) {
				do {
					radius += scale / 5 * (0.5 - RNG.NextDouble());
					radius = radius > scale / 2 ? scale / 2 : radius;
					radius = radius < scale / 10 ? scale / 10 : radius;
				} while (radius < scale / 10 || radius > scale / 2);
				point = new PolygonPoint(radius * Math.Cos((PI_2 * i) / vertexCount),
										  radius * Math.Sin((PI_2 * i) / vertexCount));
				points[i] = point;
			}
			return new Polygon(points);
		}
	}
}