axiosengine/axios/Common/Decomposition/CDT/Polygon/Polygon.cs

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2012-03-19 23:57:59 +00:00
/* 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.
*/
// Changes from the Java version
// Polygon constructors sprused up, checks for 3+ polys
// Naming of everything
// getTriangulationMode() -> TriangulationMode { get; }
// Exceptions replaced
// Future possibilities
// We have a lot of Add/Clear methods -- we may prefer to just expose the container
// Some self-explanitory methods may deserve commenting anyways
using System;
using System.Collections.Generic;
using System.Linq;
using Poly2Tri.Triangulation.Delaunay;
namespace Poly2Tri.Triangulation.Polygon
{
public class Polygon : Triangulatable
{
protected List<Polygon> _holes;
protected PolygonPoint _last;
protected List<TriangulationPoint> _points = new List<TriangulationPoint>();
protected List<TriangulationPoint> _steinerPoints;
protected List<DelaunayTriangle> _triangles;
/// <summary>
/// Create a polygon from a list of at least 3 points with no duplicates.
/// </summary>
/// <param name="points">A list of unique points</param>
public Polygon(IList<PolygonPoint> points)
{
if (points.Count < 3) throw new ArgumentException("List has fewer than 3 points", "points");
// Lets do one sanity check that first and last point hasn't got same position
// Its something that often happen when importing polygon data from other formats
if (points[0].Equals(points[points.Count - 1])) points.RemoveAt(points.Count - 1);
_points.AddRange(points.Cast<TriangulationPoint>());
}
/// <summary>
/// Create a polygon from a list of at least 3 points with no duplicates.
/// </summary>
/// <param name="points">A list of unique points.</param>
public Polygon(IEnumerable<PolygonPoint> points) : this((points as IList<PolygonPoint>) ?? points.ToArray())
{
}
public Polygon()
{
}
public IList<Polygon> Holes
{
get { return _holes; }
}
#region Triangulatable Members
public TriangulationMode TriangulationMode
{
get { return TriangulationMode.Polygon; }
}
public IList<TriangulationPoint> Points
{
get { return _points; }
}
public IList<DelaunayTriangle> Triangles
{
get { return _triangles; }
}
public void AddTriangle(DelaunayTriangle t)
{
_triangles.Add(t);
}
public void AddTriangles(IEnumerable<DelaunayTriangle> list)
{
_triangles.AddRange(list);
}
public void ClearTriangles()
{
if (_triangles != null) _triangles.Clear();
}
/// <summary>
/// Creates constraints and populates the context with points
/// </summary>
/// <param name="tcx">The context</param>
public void PrepareTriangulation(TriangulationContext tcx)
{
if (_triangles == null)
{
_triangles = new List<DelaunayTriangle>(_points.Count);
}
else
{
_triangles.Clear();
}
// Outer constraints
for (int i = 0; i < _points.Count - 1; i++)
{
tcx.NewConstraint(_points[i], _points[i + 1]);
}
tcx.NewConstraint(_points[0], _points[_points.Count - 1]);
tcx.Points.AddRange(_points);
// Hole constraints
if (_holes != null)
{
foreach (Polygon p in _holes)
{
for (int i = 0; i < p._points.Count - 1; i++)
{
tcx.NewConstraint(p._points[i], p._points[i + 1]);
}
tcx.NewConstraint(p._points[0], p._points[p._points.Count - 1]);
tcx.Points.AddRange(p._points);
}
}
if (_steinerPoints != null)
{
tcx.Points.AddRange(_steinerPoints);
}
}
#endregion
public void AddSteinerPoint(TriangulationPoint point)
{
if (_steinerPoints == null)
{
_steinerPoints = new List<TriangulationPoint>();
}
_steinerPoints.Add(point);
}
public void AddSteinerPoints(List<TriangulationPoint> points)
{
if (_steinerPoints == null)
{
_steinerPoints = new List<TriangulationPoint>();
}
_steinerPoints.AddRange(points);
}
public void ClearSteinerPoints()
{
if (_steinerPoints != null)
{
_steinerPoints.Clear();
}
}
/// <summary>
/// Add a hole to the polygon.
/// </summary>
/// <param name="poly">A subtraction polygon fully contained inside this polygon.</param>
public void AddHole(Polygon poly)
{
if (_holes == null) _holes = new List<Polygon>();
_holes.Add(poly);
// XXX: tests could be made here to be sure it is fully inside
// addSubtraction( poly.getPoints() );
}
/// <summary>
/// Inserts newPoint after point.
/// </summary>
/// <param name="point">The point to insert after in the polygon</param>
/// <param name="newPoint">The point to insert into the polygon</param>
public void InsertPointAfter(PolygonPoint point, PolygonPoint newPoint)
{
// Validate that
int index = _points.IndexOf(point);
if (index == -1)
throw new ArgumentException(
"Tried to insert a point into a Polygon after a point not belonging to the Polygon", "point");
newPoint.Next = point.Next;
newPoint.Previous = point;
point.Next.Previous = newPoint;
point.Next = newPoint;
_points.Insert(index + 1, newPoint);
}
/// <summary>
/// Inserts list (after last point in polygon?)
/// </summary>
/// <param name="list"></param>
public void AddPoints(IEnumerable<PolygonPoint> list)
{
PolygonPoint first;
foreach (PolygonPoint p in list)
{
p.Previous = _last;
if (_last != null)
{
p.Next = _last.Next;
_last.Next = p;
}
_last = p;
_points.Add(p);
}
first = (PolygonPoint) _points[0];
_last.Next = first;
first.Previous = _last;
}
/// <summary>
/// Adds a point after the last in the polygon.
/// </summary>
/// <param name="p">The point to add</param>
public void AddPoint(PolygonPoint p)
{
p.Previous = _last;
p.Next = _last.Next;
_last.Next = p;
_points.Add(p);
}
/// <summary>
/// Removes a point from the polygon.
/// </summary>
/// <param name="p"></param>
public void RemovePoint(PolygonPoint p)
{
PolygonPoint next, prev;
next = p.Next;
prev = p.Previous;
prev.Next = next;
next.Previous = prev;
_points.Remove(p);
}
}
}