From 2bb0740b68fdb62d45adc00204b3990ca42ade77 Mon Sep 17 00:00:00 2001 From: Jaron Kent-Dobias Date: Mon, 22 Aug 2016 10:11:14 -0400 Subject: started repo again without all the data files gunking the works --- src/fortune/voronoi.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 src/fortune/voronoi.c (limited to 'src/fortune/voronoi.c') diff --git a/src/fortune/voronoi.c b/src/fortune/voronoi.c new file mode 100644 index 0000000..dc9945f --- /dev/null +++ b/src/fortune/voronoi.c @@ -0,0 +1,103 @@ +# +#include "defs.h" + +struct Site *sites; +int nsites; +int siteidx; +int sqrt_nsites; +int nvertices; +struct Freelist sfl; +struct Site *bottomsite; + +/* implicit parameters: nsites, sqrt_nsites, xmin, xmax, ymin, ymax, + deltax, deltay (can all be estimates). + Performance suffers if they are wrong; better to make nsites, + deltax, and deltay too big than too small. (?) */ + +void voronoi(triangulate, nextsite) int triangulate; +struct Site *(*nextsite)(); +{ + struct Site *newsite, *bot, *top, *temp, *p; + struct Site *v; + struct Point newintstar; + int pm; + struct Halfedge *lbnd, *rbnd, *llbnd, *rrbnd, *bisector; + struct Edge *e; + + PQinitialize(); + bottomsite = (*nextsite)(); + out_site(bottomsite); + ELinitialize(); + + newsite = (*nextsite)(); + while (1) { + if (!PQempty()) + newintstar = PQ_min(); + + if (newsite != (struct Site *)NULL && + (PQempty() || newsite->coord.y < newintstar.y || + (newsite->coord.y == newintstar.y && + newsite->coord.x < newintstar.x))) {/* new site is smallest */ + out_site(newsite); + lbnd = ELleftbnd(&(newsite->coord)); + rbnd = ELright(lbnd); + bot = rightreg(lbnd); + e = bisect(bot, newsite); + bisector = HEcreate(e, le); + ELinsert(lbnd, bisector); + if ((p = intersect(lbnd, bisector)) != (struct Site *)NULL) { + PQdelete(lbnd); + PQinsert(lbnd, p, dist(p, newsite)); + }; + lbnd = bisector; + bisector = HEcreate(e, re); + ELinsert(lbnd, bisector); + if ((p = intersect(bisector, rbnd)) != (struct Site *)NULL) { + PQinsert(bisector, p, dist(p, newsite)); + }; + newsite = (*nextsite)(); + } else if (!PQempty()) + /* intersection is smallest */ + { + lbnd = PQextractmin(); + llbnd = ELleft(lbnd); + rbnd = ELright(lbnd); + rrbnd = ELright(rbnd); + bot = leftreg(lbnd); + top = rightreg(rbnd); + out_triple(bot, top, rightreg(lbnd)); + v = lbnd->vertex; + makevertex(v); + endpoint(lbnd->ELedge, lbnd->ELpm, v); + endpoint(rbnd->ELedge, rbnd->ELpm, v); + ELdelete(lbnd); + PQdelete(rbnd); + ELdelete(rbnd); + pm = le; + if (bot->coord.y > top->coord.y) { + temp = bot; + bot = top; + top = temp; + pm = re; + } + e = bisect(bot, top); + bisector = HEcreate(e, pm); + ELinsert(llbnd, bisector); + endpoint(e, re - pm, v); + deref(v); + if ((p = intersect(llbnd, bisector)) != (struct Site *)NULL) { + PQdelete(llbnd); + PQinsert(llbnd, p, dist(p, bot)); + }; + if ((p = intersect(bisector, rrbnd)) != (struct Site *)NULL) { + PQinsert(bisector, p, dist(p, bot)); + }; + } else + break; + }; + + for (lbnd = ELright(ELleftend); lbnd != ELrightend; lbnd = ELright(lbnd)) { + e = lbnd->ELedge; + out_ep(e); + }; +} -- cgit v1.2.3-70-g09d2