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#
#include "defs.h"
#include <math.h>
void geominit() {
struct Edge e;
double sn;
freeinit(&efl, sizeof e);
nvertices = 0;
nedges = 0;
sn = nsites + 4;
sqrt_nsites = sqrt(sn);
deltay = ymax - ymin;
deltax = xmax - xmin;
}
struct Edge *bisect(s1, s2) struct Site *s1, *s2;
{
double dx, dy, adx, ady;
struct Edge *newedge;
newedge = (struct Edge *)getfree(&efl);
newedge->reg[0] = s1;
newedge->reg[1] = s2;
ref(s1);
ref(s2);
newedge->ep[0] = (struct Site *)NULL;
newedge->ep[1] = (struct 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;
out_bisector(newedge);
nedges += 1;
return (newedge);
}
struct Site *intersect(el1, el2) struct Halfedge *el1, *el2;
{
struct Edge *e1, *e2, *e;
struct Halfedge *el;
double d, xint, yint;
int right_of_site;
struct Site *v;
e1 = el1->ELedge;
e2 = el2->ELedge;
if (e1 == (struct Edge *)NULL || e2 == (struct Edge *)NULL)
return ((struct Site *)NULL);
if (e1->reg[1] == e2->reg[1])
return ((struct Site *)NULL);
d = e1->a * e2->b - e1->b * e2->a;
/* printf("intersect: d=%g\n", d); */
if (-1.0e-20 < d && d < 1.0e-20) {
return ((struct Site *)NULL);
};
xint = (e1->c * e2->b - e2->c * e1->b) / d;
yint = (e2->c * e1->a - e1->c * e2->a) / d;
if ((e1->reg[1]->coord.y < e2->reg[1]->coord.y) ||
(e1->reg[1]->coord.y == e2->reg[1]->coord.y &&
e1->reg[1]->coord.x < e2->reg[1]->coord.x)) {
el = el1;
e = e1;
} else {
el = el2;
e = e2;
};
right_of_site = xint >= e->reg[1]->coord.x;
if ((right_of_site && el->ELpm == le) || (!right_of_site && el->ELpm == re))
return ((struct Site *)NULL);
v = (struct Site *)getfree(&sfl);
v->refcnt = 0;
v->coord.x = xint;
v->coord.y = yint;
return (v);
}
/* returns 1 if p is to right of halfedge e */
int right_of(el, p) struct Halfedge *el;
struct Point *p;
{
struct Edge *e;
struct Site *topsite;
int right_of_site, above, fast;
double dxp, dyp, dxs, t1, t2, t3, yl;
e = el->ELedge;
topsite = e->reg[1];
right_of_site = p->x > topsite->coord.x;
if (right_of_site && el->ELpm == le)
return (1);
if (!right_of_site && el->ELpm == re)
return (0);
if (e->a == 1.0) {
dyp = p->y - topsite->coord.y;
dxp = p->x - topsite->coord.x;
fast = 0;
if ((!right_of_site && e->b < 0.0) | (right_of_site && e->b >= 0.0)) {
above = dyp >= e->b * dxp;
fast = above;
} else {
above = p->x + p->y * e->b > e->c;
if (e->b < 0.0)
above = !above;
if (!above)
fast = 1;
};
if (!fast) {
dxs = topsite->coord.x - (e->reg[0])->coord.x;
above = e->b * (dxp * dxp - dyp * dyp) <
dxs * dyp * (1.0 + 2.0 * dxp / dxs + e->b * e->b);
if (e->b < 0.0)
above = !above;
};
} else /*e->b==1.0 */
{
yl = e->c - e->a * p->x;
t1 = p->y - yl;
t2 = p->x - topsite->coord.x;
t3 = yl - topsite->coord.y;
above = t1 * t1 > t2 * t2 + t3 * t3;
};
return (el->ELpm == le ? above : !above);
}
void endpoint(e, lr, s) struct Edge *e;
int lr;
struct Site *s;
{
e->ep[lr] = s;
ref(s);
if (e->ep[re - lr] == (struct Site *)NULL) {
} else {
out_ep(e);
deref(e->reg[le]);
deref(e->reg[re]);
makefree((struct Freenode *)e, &efl);
}
}
double dist(s, t) struct Site *s, *t;
{
double dx, dy;
dx = s->coord.x - t->coord.x;
dy = s->coord.y - t->coord.y;
return (sqrt(dx * dx + dy * dy));
}
void makevertex(v) struct Site *v;
{
v->sitenbr = nvertices;
nvertices += 1;
out_vertex(v);
}
void deref(v) struct Site *v;
{
v->refcnt -= 1;
if (v->refcnt == 0)
makefree((struct Freenode *)v, &sfl);
}
void ref(v) struct Site *v;
{ v->refcnt += 1; }
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