97 lines
3.9 KiB
C#
97 lines
3.9 KiB
C#
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/******************************************************************************
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*
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* The MIT License (MIT)
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*
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* MIConvexHull, Copyright (c) 2015 David Sehnal, Matthew Campbell
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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*****************************************************************************/
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using System.Collections.Generic;
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using System.Linq;
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namespace NWH.DWP2.MiConvexHull
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{
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/*
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* Code here handles triangulation related stuff.
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*/
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/// <summary>
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/// Class ConvexHullAlgorithm.
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/// </summary>
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internal partial class ConvexHullAlgorithm
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{
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/// <summary>
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/// Computes the Delaunay triangulation.
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/// </summary>
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/// <typeparam name="TVertex">The type of the t vertex.</typeparam>
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/// <typeparam name="TCell">The type of the t cell.</typeparam>
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/// <param name="data">The data.</param>
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/// <returns>TCell[].</returns>
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internal static TCell[] GetDelaunayTriangulation<TVertex, TCell>(IList<TVertex> data)
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where TCell : TriangulationCell<TVertex, TCell>, new()
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where TVertex : IVertex
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{
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ConvexHullAlgorithm ch =
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new ConvexHullAlgorithm(data.Cast<IVertex>().ToArray(), true, Constants.DefaultPlaneDistanceTolerance);
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ch.GetConvexHull();
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ch.RemoveUpperFaces();
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return ch.GetConvexFaces<TVertex, TCell>();
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}
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/// <summary>
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/// Removes up facing Tetrahedrons from the triangulation.
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/// </summary>
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private void RemoveUpperFaces()
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{
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IndexBuffer delaunayFaces = ConvexFaces;
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int dimension = NumOfDimensions - 1;
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// Remove the "upper" faces
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for (int i = delaunayFaces.Count - 1; i >= 0; i--)
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{
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int candidateIndex = delaunayFaces[i];
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ConvexFaceInternal candidate = FacePool[candidateIndex];
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if (candidate.Normal[dimension] >= 0.0)
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{
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for (int fi = 0; fi < candidate.AdjacentFaces.Length; fi++)
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{
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int af = candidate.AdjacentFaces[fi];
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if (af >= 0)
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{
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ConvexFaceInternal face = FacePool[af];
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for (int j = 0; j < face.AdjacentFaces.Length; j++)
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{
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if (face.AdjacentFaces[j] == candidateIndex)
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{
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face.AdjacentFaces[j] = -1;
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}
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}
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}
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}
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delaunayFaces[i] = delaunayFaces[delaunayFaces.Count - 1];
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delaunayFaces.Pop();
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}
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}
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}
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}
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}
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