private void processSiteEvent(final Event newSite) {
HalfEdge lBnd = coast.getHalfEdgeToTheLeftOf((newSite));
HalfEdge rBnd = coast.getHalfEdgeToTheRightOf(lBnd);
// if this half-edge has no edge,bot = bottom site (whatever that is)
Site bot = lBnd.getRightReg(bottomSite);
Edge e = edgeBisector.newEdgeThatBisects(bot, newSite);
HalfEdge bisector1 = new HalfEdge(e, Edge.LE);
// insert this new bisector edge between the left and right bounds
coast.insert(lBnd, bisector1);
// if the new bisector intersects with the left edge,
// remove the left edge's vertex, and put in the new one
Site p = lBnd.intersect(bisector1);
if (p != null) {
events.delete(lBnd);
events.insert(lBnd, p, p.distTo(newSite));
}
HalfEdge bisector2 = new HalfEdge(e, Edge.RE);
// insert the new HE to the right of the original bisector
coast.insert(bisector1, bisector2);
// if this new bisector intersects with the new HalfEdge
p = bisector2.intersect(rBnd);
if (p != null) {
// push the HE into the ordered linked list of vertices
events.insert(bisector2, p, p.distTo(newSite));
}
}
private void processCircleEvent() {
// pop the HalfEdge with the lowest vector off the ordered list
// of vectors
HalfEdge lBnd = events.extractMin();
// get the HalfEdge to the left of the above HE
HalfEdge llBnd = coast.getHalfEdgeToTheLeftOf(lBnd);
// get the HalfEdge to the right of the above HE
HalfEdge rBnd = coast.getHalfEdgeToTheRightOf(lBnd);
// get the HalfEdge to the right of the HE to the right of the
// lowest HE
HalfEdge rrBnd = coast.getHalfEdgeToTheRightOf(rBnd);
// get the Site to the left of the left HE which it bisects
Site bot = lBnd.getLeftReg(bottomSite);
// get the Site to the right of the right HE which it bisects
Site top = rBnd.getRightReg(bottomSite);
Site v = lBnd.vertex; // get the vertex that caused this event
// set the vertex number - couldn't do this
// earlier since we didn't know when it would be processed
v.sitenbr = nextVertexNbr++;
endpoint(lBnd.edge, lBnd.side, v);
// set the endpoint of
// the left HalfEdge to be this vector
endpoint(rBnd.edge, rBnd.side, v);
// set the endpoint of the right HalfEdge to be this vector
coast.delete(lBnd);
events.delete(rBnd);
// remove all vertex events to do with the right HE
coast.delete(rBnd); // mark the right HE for
// deletion - can't delete yet because there might be pointers
// to it in Hash Map
int pm = Edge.LE; // set the pm variable to zero
if (bot.y > top.y) {
// if the site to the left of the event is higher than the
// Site
// to the right of it, then swap them and set the 'pm'
// variable to 1
Site temp = bot;
bot = top;
top = temp;
pm = Edge.RE;
}
Edge e = edgeBisector.newEdgeThatBisects(bot, top); // create an Edge (or
// line)
// that is between the two Sites. This creates the formula of
// the line, and assigns a line number to it
HalfEdge bisector = new HalfEdge(e, pm); // create a HE from the Edge
// 'e',
// and make it point to that edge
// with its ELedge field
coast.insert(llBnd, bisector); // insert the new bisector to the
// right of the left HE
endpoint(e, Edge.RE - pm, v); // set one endpoint to the new edge
// to be the vector point 'v'.
// If the site to the left of this bisector is higher than the
// right Site, then this endpoint
// is put in position 0; otherwise in pos 1
// if left HE and the new bisector intersect, then delete
// the left HE, and reinsert it
Site p = llBnd.intersect(bisector);
if (p != null) {
events.delete(llBnd);
events.insert(llBnd, p, p.distTo(bot));
}
// if right HE and the new bisector intersect, then
// reinsert it
p = bisector.intersect(rrBnd);
if (p != null) {
events.insert(bisector, p, p.distTo(bot));
}
}