public static double getHighestAngle(DCHalfEdge edge, Point focus) {
Point target;
if (edge.start.compareTo(focus) == 0) {
target = edge.end;
} else {
target = edge.start;
}
// reset edge with higher point as start;
// return angle of edge from start to end
return Geom.cartToPolar(target.getX() - focus.getX(), target.getY() - focus.getY())[1];
}
// find centroid of a polygon
public static Point findCentroid(Polygon polygon) {
DoublyConnectedEdgeList dc = Geom.linesToDCEdgeList(polygon);
return Geom.findCentroid(dc);
}
public static char rayTypePointInPolygon(Point q, DoublyConnectedEdgeList p) {
double width = 5000;
int i, i1; // point index; i1 = 1-1 mod n;
int n = p.edges.size();
int d = 2; // dimension index
int Rcross = 0; // number of right edge/ray crossings
int Lcross = 0; // number of left edge/ray crossings
boolean Rstrad, Lstrad; // flags that indicate the edge straddles the x axis
// Vector<CompPoint> p = new Vector<CompPoint>();
// for each edge in poly, see if crosses rays
/*for(i=0;i<n;i++){
DCHalfEdge edge = p.edge.get(i);
CompPoint newPoint = new CompPoint(edge.start.getX()-q.getX(),edge.start.getY()-q.getY());
}*/
// check if p is a vertex of the polygon
for (i = 0; i < n; i++) {
i1 = (i + n - 1) % n;
DCHalfEdge edge = p.edges.get(i);
if (q.compareTo(edge.start) == 0 || q.compareTo(edge.end) == 0) {
return 'v';
}
}
DCHalfEdge rEdge = new DCHalfEdge(q, new Point(width, q.getY()));
DCHalfEdge lEdge = new DCHalfEdge(q, new Point(0, q.getY()));
Rcross = Geom.edgeIntersectsPolygon(rEdge, p).size();
Lcross = Geom.edgeIntersectsPolygon(lEdge, p).size();
// System.out.println("Rcross = "+Rcross+",Lcross="+Lcross);
/*i1=(i+n-1)%n;
DCHalfEdge edge1 = p.edges.get(i1);
Rstrad = (edge.start.getY()>q.getY())!=(edge1.start.getY()>q.getY());
Lstrad = (edge.start.getY()<q.getY())!=(edge1.start.getY()<q.getY());
if(Rstrad|| Lstrad){
double x = (edge.start.getX()*edge1.start.getY()-edge1.start.getX()*edge.start.getY())/(edge1.start.getY()-edge.start.getY());
if(Rstrad && x> q.getX()){
Rcross++;
}
if(Lstrad && x> q.getX()){
Lcross++;
}
}
}
*/
// q is on an edge if L/Rcross counts are not the same parity
if ((Rcross % 2) != (Lcross % 2)) {
return 'e';
}
if ((Rcross % 2) == 1) {
return 'i';
} else {
return 'o';
}
}
public static DCHalfEdge getIntersectedEdge(
Point focus, Point direction, DCHalfEdge parentEdge, DoublyConnectedEdgeList border) {
DCHalfEdge edge = new DCHalfEdge(focus, direction);
double dx = direction.getX() - focus.getX(); // direction x
double dy = direction.getY() - focus.getY(); // direction y
DCHalfEdge borderEdge = null; // selected border edge for intersection;
double[] thetas = border.getBorderPoints(focus); // degrees of all points along the border
double edgeTheta = Geom.cartToPolar(dx, dy)[1]; // degree of edge
double selectedTheta = -1;
// myParent.println("\n\n\n edgeTheta="+edgeTheta+"\n\n\n");
for (int i = 0;
i < thetas.length;
i++) { // iterate through all edges and look for correct point of intersection
// myParent.println("edge "+i+" theta="+thetas[i]+" x="+border.edges.get(i).start.getX()+"
// y="+border.edges.get(i).start.getY());
int after = i + 1;
if (i == thetas.length - 1) {
after = 0;
}
if (thetas[after]
> thetas[
i]) { // special case where angle of previous edge is greater than angle of current
// edge
// myParent.println("call special case");
if (edgeTheta >= thetas[after]
|| edgeTheta < thetas[i]) { // detects quadrant of intersection for special case
if (edgeTheta > thetas[i]) {
borderEdge = border.edges.get(i - 1);
selectedTheta = thetas[i];
} else {
borderEdge = border.edges.get(i);
selectedTheta = thetas[after];
}
/*myParent.println("\n\n\n edgeTheta="+edgeTheta);
myParent.println("theta i="+thetas[i]);
myParent.println("theta after="+thetas[after]);
myParent.println("selected theta="+selectedTheta);
myParent.println("start x,y,="+focus.getX()+","+focus.getY());
myParent.println("end x,y,="+direction.getX()+","+direction.getY());
myParent.println("intersection x,y,="+intersection.getX()+","+intersection.getY()+"\n\n\n");*/
parentEdge.infiniteEdge = 1;
break;
}
} else { // otherwise all thetas should be greater than the preceeding theta
if (edgeTheta <= thetas[i]
&& edgeTheta > thetas[after]) { // detects quadrant of intersection
borderEdge = border.edges.get(i);
selectedTheta = thetas[i];
break;
}
}
}
return borderEdge;
}
