/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.triangulate.quadedge;
import java.util.Collection;
import java.util.LinkedList;
/**
* A framework to visit sets of edge-connected {@link QuadEdgeTriangle}s in breadth-first order
*
* @author Martin Davis
* @version 1.0
*/
public class EdgeConnectedTriangleTraversal {
private LinkedList triQueue = new LinkedList();
public EdgeConnectedTriangleTraversal() {}
public void init(QuadEdgeTriangle tri) {
triQueue.addLast(tri);
}
/**
* Called to initialize the traversal queue with a given set of {@link QuadEdgeTriangle}s
*
* @param tris a collection of QuadEdgeTriangle
*/
public void init(Collection tris) {
triQueue.addAll(tris);
}
/**
* Subclasses can call this method to add a triangle to the end of the queue. This is useful for
* initializing the queue to a chosen set of triangles.
*
* @param tri a triangle
*/
/*
* protected void addLast(QuadEdgeTriangle tri) { triQueue.addLast(tri); }
*/
/**
* Subclasses call this method to perform the visiting process.
*/
public void visitAll(TraversalVisitor visitor) {
while (!triQueue.isEmpty()) {
QuadEdgeTriangle tri = (QuadEdgeTriangle) triQueue.removeFirst();
process(tri, visitor);
}
}
private void process(QuadEdgeTriangle currTri, TraversalVisitor visitor) {
currTri.getNeighbours();
for (int i = 0; i < 3; i++) {
QuadEdgeTriangle neighTri = (QuadEdgeTriangle) currTri.getEdge(i).sym().getData();
if (neighTri == null)
continue;
if (visitor.visit(currTri, i, neighTri))
triQueue.addLast(neighTri);
}
}
}