Edge *bisect(Site * s1, Site * s2)
{
double dx, dy, adx, ady;
Edge *newedge;
newedge = (Edge *) getfree(&efl);
newedge->reg[0] = s1;
newedge->reg[1] = s2;
ref(s1);
ref(s2);
newedge->ep[0] = (Site *) NULL;
newedge->ep[1] = (Site *) NULL;
dx = s2->coord.x - s1->coord.x;
dy = s2->coord.y - s1->coord.y;
adx = dx > 0 ? dx : -dx;
ady = dy > 0 ? dy : -dy;
newedge->c =
s1->coord.x * dx + s1->coord.y * dy + (dx * dx + dy * dy) * 0.5;
if (adx > ady) {
newedge->a = 1.0;
newedge->b = dy / dx;
newedge->c /= dx;
} else {
newedge->b = 1.0;
newedge->a = dx / dy;
newedge->c /= dy;
};
newedge->edgenbr = nedges;
#ifdef STANDALONE
out_bisector(newedge);
#endif
nedges += 1;
return (newedge);
}
struct Edge * VoronoiDiagramGenerator::bisect(struct Site *s1,struct Site *s2)
{
float dx,dy,adx,ady;
struct Edge *newedge;
newedge = (struct Edge *) getfree(&efl);
newedge -> reg[0] = s1; //store the sites that this edge is bisecting
newedge -> reg[1] = s2;
ref(s1);
ref(s2);
newedge -> ep[0] = (struct Site *) NULL; //to begin with, there are no endpoints on the bisector - it goes to infinity
newedge -> ep[1] = (struct Site *) NULL;
dx = s2->coord.x - s1->coord.x; //get the difference in x dist between the sites
dy = s2->coord.y - s1->coord.y;
adx = dx>0 ? dx : -dx; //make sure that the difference in positive
ady = dy>0 ? dy : -dy;
newedge -> c = (float)(s1->coord.x * dx + s1->coord.y * dy + (dx*dx + dy*dy)*0.5);//get the slope of the line
if (adx>ady)
{
newedge -> a = 1.0; newedge -> b = dy/dx; newedge -> c /= dx;//set formula of line, with x fixed to 1
}
else
{
newedge -> b = 1.0; newedge -> a = dx/dy; newedge -> c /= dy;//set formula of line, with y fixed to 1
};
newedge -> edgenbr = nedges;
//printf("\nbisect(%d) ((%f,%f) and (%f,%f)",nedges,s1->coord.x,s1->coord.y,s2->coord.x,s2->coord.y);
out_bisector(newedge);
nedges += 1;
return(newedge);
}
