ConstrainedPointSet.java

/* Poly2Tri
 * Copyright (c) 2009-2010, Poly2Tri Contributors
 * http://code.google.com/p/poly2tri/
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package org.poly2tri.triangulation.sets;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.poly2tri.triangulation.TriangulationContext;
import org.poly2tri.triangulation.TriangulationMode;
import org.poly2tri.triangulation.TriangulationPoint;

/**
 * Extends the PointSet by adding some Constraints on how it will be triangulated<br>
 * A constraint defines an edge between two points in the set, these edges can not
 * be crossed. They will be enforced triangle edges after a triangulation.
 * <p>
 * 
 * 
 * @author Thomas �hl�n, thahlen@gmail.com
 */
public class ConstrainedPointSet extends PointSet {
	int[] _index;
	List<TriangulationPoint> _constrainedPointList = null;

	public ConstrainedPointSet(List<TriangulationPoint> points, int[] index) {
		super(points);
		_index = index;
	}

	/**
	 * 
	 * @param points - A list of all points in PointSet
	 * @param constraints - Pairs of two points defining a constraint, all points <b>must</b> be part of given PointSet!
	 */
	public ConstrainedPointSet(List<TriangulationPoint> points,
			List<TriangulationPoint> constraints) {
		super(points);
		_constrainedPointList = new ArrayList<TriangulationPoint>();
		_constrainedPointList.addAll(constraints);
	}

	@Override
	public TriangulationMode getTriangulationMode() {
		return TriangulationMode.CONSTRAINED;
	}

	public int[] getEdgeIndex() {
		return _index;
	}

	@SuppressWarnings("rawtypes")
	@Override
	public void prepareTriangulation(TriangulationContext tcx) {
		super.prepareTriangulation(tcx);
		if (_constrainedPointList != null) {
			TriangulationPoint p1, p2;
			Iterator iterator = _constrainedPointList.iterator();
			while (iterator.hasNext()) {
				p1 = (TriangulationPoint) iterator.next();
				p2 = (TriangulationPoint) iterator.next();
				tcx.newConstraint(p1, p2);
			}
		} else {
			for (int i = 0; i < _index.length; i += 2) {
				// XXX: must change!!
				tcx.newConstraint(_points.get(_index[i]), _points
						.get(_index[i + 1]));
			}
		}
	}

	/**
	 * TODO: TO BE IMPLEMENTED!
	 * Peforms a validation on given input<br>
	 * 1. Check's if there any constraint edges are crossing or collinear<br>
	 * 2. 
	 * @return
	 */
	public boolean isValid() {
		return true;
	}
}