compute convex hulls using qhull

   see unix.c for full interface

   Copyright (c) 1993-2015, The Geometry Center

#include "libqhull/libqhull.h"


#if __cplusplus
extern "C" {
  int isatty(int);

#elif _MSC_VER
#define isatty _isatty
/* int _isatty(int); */

int isatty(int);  /* returns 1 if stdin is a tty
                   if "Undefined symbol" this can be deleted along with call in main() */


    long prompt for qconvex

    restricted version of libqhull.c

    concise prompt below

/* duplicated in qconvex.htm */
char hidden_options[]=" d v H Qbb Qf Qg Qm Qr Qu Qv Qx Qz TR E V Fp Gt Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 ";

char qh_prompta[]= "\n\
qconvex- compute the convex hull\n\
    http://www.qhull.org  %s\n\
input (stdin):\n\
    first lines: dimension and number of points (or vice-versa).\n\
    other lines: point coordinates, best if one point per line\n\
    comments:    start with a non-numeric character\n\
    Qt   - triangulated output\n\
    QJ   - joggled input instead of merged facets\n\
    Qc   - keep coplanar points with nearest facet\n\
    Qi   - keep interior points with nearest facet\n\
Qhull control options:\n\
    Qbk:n   - scale coord k so that low bound is n\n\
      QBk:n - scale coord k so that upper bound is n (QBk is %2.2g)\n\
    QbB  - scale input to unit cube centered at the origin\n\
    Qbk:0Bk:0 - remove k-th coordinate from input\n\
    QJn  - randomly joggle input in range [-n,n]\n\
    QRn  - random rotation (n=seed, n=0 time, n=-1 time/no rotate)\n\
%s%s%s%s";  /* split up qh_prompt for Visual C++ */
char qh_promptb[]= "\
    Qs   - search all points for the initial simplex\n\
    QGn  - good facet if visible from point n, -n for not visible\n\
    QVn  - good facet if it includes point n, -n if not\n\
char qh_promptc[]= "\
Trace options:\n\
    T4   - trace at level n, 4=all, 5=mem/gauss, -1= events\n\
    Tc   - check frequently during execution\n\
    Ts   - print statistics\n\
    Tv   - verify result: structure, convexity, and point inclusion\n\
    Tz   - send all output to stdout\n\
    TFn  - report summary when n or more facets created\n\
    TI file - input data from file, no spaces or single quotes\n\
    TO file - output results to file, may be enclosed in single quotes\n\
    TPn  - turn on tracing when point n added to hull\n\
     TMn - turn on tracing at merge n\n\
     TWn - trace merge facets when width > n\n\
    TVn  - stop qhull after adding point n, -n for before (see TCn)\n\
     TCn - stop qhull after building cone for point n (see TVn)\n\
Precision options:\n\
    Cn   - radius of centrum (roundoff added).  Merge facets if non-convex\n\
     An  - cosine of maximum angle.  Merge facets if cosine > n or non-convex\n\
           C-0 roundoff, A-0.99/C-0.01 pre-merge, A0.99/C0.01 post-merge\n\
    Rn   - randomly perturb computations by a factor of [1-n,1+n]\n\
    Un   - max distance below plane for a new, coplanar point\n\
    Wn   - min facet width for outside point (before roundoff)\n\
Output formats (may be combined; if none, produces a summary to stdout):\n\
    f    - facet dump\n\
    G    - Geomview output (see below)\n\
    i    - vertices incident to each facet\n\
    m    - Mathematica output (2-d and 3-d)\n\
    n    - normals with offsets\n\
    o    - OFF file format (dim, points and facets; Voronoi regions)\n\
    p    - point coordinates \n\
    s    - summary (stderr)\n\
char qh_promptd[]= "\
More formats:\n\
    Fa   - area for each facet\n\
    FA   - compute total area and volume for option 's'\n\
    Fc   - count plus coplanar points for each facet\n\
           use 'Qc' (default) for coplanar and 'Qi' for interior\n\
    FC   - centrum for each facet\n\
    Fd   - use cdd format for input (homogeneous with offset first)\n\
    FD   - use cdd format for numeric output (offset first)\n\
    FF   - facet dump without ridges\n\
    Fi   - inner plane for each facet\n\
    FI   - ID for each facet\n\
    Fm   - merge count for each facet (511 max)\n\
    Fn   - count plus neighboring facets for each facet\n\
    FN   - count plus neighboring facets for each point\n\
    Fo   - outer plane (or max_outside) for each facet\n\
    FO   - options and precision constants\n\
    FP   - nearest vertex for each coplanar point\n\
    FQ   - command used for qconvex\n\
    Fs   - summary: #int (8), dimension, #points, tot vertices, tot facets,\n\
                      for output: #vertices, #facets,\n\
                                  #coplanar points, #non-simplicial facets\n\
                    #real (2), max outer plane, min vertex\n\
    FS   - sizes:   #int (0) \n\
                    #real (2) tot area, tot volume\n\
    Ft   - triangulation with centrums for non-simplicial facets (OFF format)\n\
    Fv   - count plus vertices for each facet\n\
    FV   - average of vertices (a feasible point for 'H')\n\
    Fx   - extreme points (in order for 2-d)\n\
char qh_prompte[]= "\
Geomview output (2-d, 3-d, and 4-d)\n\
    Ga   - all points as dots\n\
     Gp  -  coplanar points and vertices as radii\n\
     Gv  -  vertices as spheres\n\
    Gi   - inner planes only\n\
     Gn  -  no planes\n\
     Go  -  outer planes only\n\
    Gc   - centrums\n\
    Gh   - hyperplane intersections\n\
    Gr   - ridges\n\
    GDn  - drop dimension n in 3-d and 4-d output\n\
Print options:\n\
    PAn  - keep n largest facets by area\n\
    Pdk:n - drop facet if normal[k] <= n (default 0.0)\n\
    PDk:n - drop facet if normal[k] >= n\n\
    Pg   - print good facets (needs 'QGn' or 'QVn')\n\
    PFn  - keep facets whose area is at least n\n\
    PG   - print neighbors of good facets\n\
    PMn  - keep n facets with most merges\n\
    Po   - force output.  If error, output neighborhood of facet\n\
    Pp   - do not report precision problems\n\
    .    - list of all options\n\
    -    - one line descriptions of all options\n\
    -V   - version\n\
/* for opts, don't assign 'e' or 'E' to a flag (already used for exponent) */


    synopsis for qhull
char qh_prompt2[]= "\n\
qconvex- compute the convex hull.  Qhull %s\n\
    input (stdin): dimension, number of points, point coordinates\n\
    comments start with a non-numeric character\n\
options (qconvex.htm):\n\
    Qt   - triangulated output\n\
    QJ   - joggled input instead of merged facets\n\
    Tv   - verify result: structure, convexity, and point inclusion\n\
    .    - concise list of all options\n\
    -    - one-line description of all options\n\
    -V   - version\n\
output options (subset):\n\
    s    - summary of results (default)\n\
    i    - vertices incident to each facet\n\
    n    - normals with offsets\n\
    p    - vertex coordinates (includes coplanar points if 'Qc')\n\
    Fx   - extreme points (convex hull vertices)\n\
    FA   - report total area and volume\n\
    FS   - compute total area and volume\n\
    o    - OFF format (dim, n, points, facets)\n\
    G    - Geomview output (2-d, 3-d, and 4-d)\n\
    m    - Mathematica output (2-d and 3-d)\n\
    QVn  - print facets that include point n, -n if not\n\
    TO file- output results to file, may be enclosed in single quotes\n\
    rbox c D2 | qconvex s n                    rbox c D2 | qconvex i\n\
    rbox c D2 | qconvex o                      rbox 1000 s | qconvex s Tv FA\n\
    rbox c d D2 | qconvex s Qc Fx              rbox y 1000 W0 | qconvex s n\n\
    rbox y 1000 W0 | qconvex s QJ              rbox d G1 D12 | qconvex QR0 FA Pp\n\
    rbox c D7 | qconvex FA TF1000\n\
/* for opts, don't assign 'e' or 'E' to a flag (already used for exponent) */


    concise prompt for qhull
char qh_prompt3[]= "\n\
Qhull %s.\n\
Except for 'F.' and 'PG', upper-case options take an argument.\n\
 incidences     mathematica    normals        OFF_format     points\n\
 summary        facet_dump\n\
 Farea          FArea_total    Fcoplanars     FCentrums      Fd_cdd_in\n\
 FD_cdd_out     FFacet_xridge  Finner         FIDs           Fmerges\n\
 Fneighbors     FNeigh_vertex  Fouter         FOptions       FPoint_near\n\
 FQhull         Fsummary       FSize          Fvertices      FVertex_ave\n\
 Fxtremes       FMaple\n\
 Gvertices      Gpoints        Gall_points    Gno_planes     Ginner\n\
 Gcentrums      Ghyperplanes   Gridges        Gouter         GDrop_dim\n\
 PArea_keep     Pdrop d0:0D0   PFacet_area_keep Pgood        PGood_neighbors\n\
 PMerge_keep    Poutput_forced Pprecision_not\n\
 QbBound 0:0.5  QbB_scale_box  Qcoplanar      QGood_point    Qinterior\n\
 QJoggle        Qrandom        QRotate        Qsearch_1st    Qtriangulate\n\
 T4_trace       Tcheck_often   Tstatistics    Tverify        Tz_stdout\n\
 TFacet_log     TInput_file    TPoint_trace   TMerge_trace   TOutput_file\n\
 TWide_trace    TVertex_stop   TCone_stop\n\
 Angle_max      Centrum_size   Random_dist    Ucoplanar_max  Wide_outside\n\


  main( argc, argv )
    processes the command line, calls qhull() to do the work, and exits

    initializes data structures
    reads points
    finishes initialization
    computes convex hull and other structures
    checks the result
    writes the output
    frees memory
int main(int argc, char *argv[]) {
  int curlong, totlong; /* used !qh_NOmem */
  int exitcode, numpoints, dim;
  coordT *points;
  boolT ismalloc;

  QHULL_LIB_CHECK /* Check for compatible library */

  if ((argc == 1) && isatty( 0 /*stdin*/)) {
    fprintf(stdout, qh_prompt2, qh_version);
  if (argc > 1 && *argv[1] == '-' && !*(argv[1]+1)) {
    fprintf(stdout, qh_prompta, qh_version, qh_DEFAULTbox,
                qh_promptb, qh_promptc, qh_promptd, qh_prompte);
  if (argc > 1 && *argv[1] == '.' && !*(argv[1]+1)) {
    fprintf(stdout, qh_prompt3, qh_version);
  if (argc > 1 && *argv[1] == '-' && *(argv[1]+1)=='V') {
      fprintf(stdout, "%s\n", qh_version2);
  qh_init_A(stdin, stdout, stderr, argc, argv);  /* sets qh qhull_command */
  exitcode= setjmp(qh errexit); /* simple statement for CRAY J916 */
  if (!exitcode) {
    qh NOerrexit = False;
    qh_checkflags(qh qhull_command, hidden_options);
    qh_initflags(qh qhull_command);
    points= qh_readpoints(&numpoints, &dim, &ismalloc);
    if (dim >= 5) {
      qh_option("Qxact_merge", NULL, NULL);
      qh MERGEexact= True; /* 'Qx' always */
    qh_init_B(points, numpoints, dim, ismalloc);
    if (qh VERIFYoutput && !qh FORCEoutput && !qh STOPpoint && !qh STOPcone)
    exitcode= qh_ERRnone;
  qh NOerrexit= True;  /* no more setjmp */
#ifdef qh_NOmem
  qh_memfreeshort(&curlong, &totlong);
  if (curlong || totlong)
    qh_fprintf_stderr(6263, "qhull internal warning (main): did not free %d bytes of long memory(%d pieces)\n",
       totlong, curlong);
  return exitcode;
} /* main */