gistfile1.java

/**
 * Looks at the triangle references in e and replaces the oldRef with the
 * newRef
 * 
 * @param e
 *            the edge
 * @param oldRef
 *            the old reference that should be replaced
 * @param newRef
 *            the new reference
 */
private void replaceTraingleRef(Edge e, Triangle oldRef, Triangle newRef) {
  if (e.getT1().equals(oldRef))
		e.setT1(newRef);
	else
		e.setT2(newRef);
}

private LinkedList<Triangle> getTrianglesOfEdge(Edge ed) {
	LinkedList<Triangle> result = new LinkedList<Triangle>();
	if (ed.getT1() != null)
		result.add(ed.getT1());
	if (ed.getT2() != null)
		result.add(ed.getT2());
	return result;
}

public Point getCommonPoint(Edge e1, Edge e2) {
	if (e2.containsPoint(e1.getP1()))
		return e1.getP1();
	if (e2.containsPoint(e1.getP2()))
		return e1.getP2();
	return null;
}

/**
 * insert a point into triangulation an correct Triangulation if necessary
 * 
 * @param p
 *            Point to insert
 */
public void insertPoint(Point p) {
	Triangle triangle;
	try {
		triangle = this.getTriangle(p);
		LinkedList<Edge> triangleEdges = triangle.getEdges();
		LinkedList<Point> outerPoints = new LinkedList<Point>();
		outerPoints.add(this.getCommonPoint(triangleEdges.get(0), triangleEdges.get(1)));
		outerPoints.add(this.getCommonPoint(triangleEdges.get(0), triangleEdges.get(2)));
		outerPoints.add(this.getCommonPoint(triangleEdges.get(1), triangleEdges.get(2)));
		// build new edges
		Edge e1 = new Edge(p, outerPoints.get(0), null, null);
		Edge e2 = new Edge(p, outerPoints.get(1), null, null);
		Edge e3 = new Edge(p, outerPoints.get(2), null, null);
		// now build triangles
		Triangle t1 = new Triangle(buildEdgeList(triangleEdges.get(0), e1, e2));
		Triangle t2 = new Triangle(buildEdgeList(triangleEdges.get(1), e2, e3));
		triangle.setEdges(buildEdgeList(triangleEdges.get(2), e3, e1));
		// set edges correctly
		this.replaceTraingleRef(triangleEdges.get(0), triangle, t1);
		this.replaceTraingleRef(triangleEdges.get(1), triangle, t2);
		e1.setT1(t1);
		e1.setT2(t2);
		e2.setT1(t1);
		e2.setT2(triangle);
		e3.setT1(t2);
		e3.setT2(triangle);
	} catch (IllegalAccessException e4) {
		e4.printStackTrace();
	}
}