forked from bartvdbraak/blender
311 lines
10 KiB
C
311 lines
10 KiB
C
/*<html><pre> -<a href="qh-user.htm"
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>-------------------------------</a><a name="TOP">-</a>
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user_eg.c
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sample code for calling qhull() from an application
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call with:
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user_eg "cube/diamond options" "delaunay options" "halfspace options"
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for example:
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user_eg # return summaries
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user_eg "n" "o" "Fp" # return normals, OFF, points
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user_eg "n Qt" "o" "Fp" # triangulated cube
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user_eg "QR0 p" "QR0 v p" "QR0 Fp" # rotate input and return points
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# 'v' returns Voronoi
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# transform is rotated for halfspaces
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main() makes three runs of qhull.
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1) compute the convex hull of a cube
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2a) compute the Delaunay triangulation of random points
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2b) find the Delaunay triangle closest to a point.
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3) compute the halfspace intersection of a diamond
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notes:
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For another example, see main() in unix.c and user_eg2.c.
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These examples, call qh_qhull() directly. They allow
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tighter control on the code loaded with Qhull.
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For a simple C++ example, see qhull_interface.cpp
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Summaries are sent to stderr if other output formats are used
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compiled by 'make user_eg'
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see qhull.h for data structures, macros, and user-callable functions.
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*/
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#include "qhull_a.h"
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/*-------------------------------------------------
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-internal function prototypes
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*/
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void print_summary (void);
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void makecube (coordT *points, int numpoints, int dim);
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void makeDelaunay (coordT *points, int numpoints, int dim, int seed);
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void findDelaunay (int dim);
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void makehalf (coordT *points, int numpoints, int dim);
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/*-------------------------------------------------
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-print_summary()
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*/
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void print_summary (void) {
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facetT *facet;
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int k;
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printf ("\n%d vertices and %d facets with normals:\n",
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qh num_vertices, qh num_facets);
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FORALLfacets {
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for (k=0; k < qh hull_dim; k++)
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printf ("%6.2g ", facet->normal[k]);
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printf ("\n");
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}
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}
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/*--------------------------------------------------
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-makecube- set points to vertices of cube
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points is numpoints X dim
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*/
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void makecube (coordT *points, int numpoints, int dim) {
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int j,k;
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coordT *point;
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for (j=0; j<numpoints; j++) {
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point= points + j*dim;
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for (k=dim; k--; ) {
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if (j & ( 1 << k))
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point[k]= 1.0;
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else
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point[k]= -1.0;
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}
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}
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} /*.makecube.*/
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/*--------------------------------------------------
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-makeDelaunay- set points for dim Delaunay triangulation of random points
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points is numpoints X dim.
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notes:
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makeDelaunay() in user_eg2.c uses qh_setdelaunay() to project points in place.
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*/
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void makeDelaunay (coordT *points, int numpoints, int dim, int seed) {
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int j,k;
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coordT *point, realr;
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printf ("seed: %d\n", seed);
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qh_RANDOMseed_( seed);
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for (j=0; j<numpoints; j++) {
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point= points + j*dim;
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for (k= 0; k < dim; k++) {
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realr= qh_RANDOMint;
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point[k]= 2.0 * realr/(qh_RANDOMmax+1) - 1.0;
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}
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}
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} /*.makeDelaunay.*/
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/*--------------------------------------------------
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-findDelaunay- find Delaunay triangle for [0.5,0.5,...]
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assumes dim < 100
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notes:
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calls qh_setdelaunay() to project the point to a parabaloid
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*/
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void findDelaunay (int dim) {
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int k;
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coordT point[ 100];
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boolT isoutside;
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realT bestdist;
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facetT *facet;
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vertexT *vertex, **vertexp;
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for (k= 0; k < dim; k++)
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point[k]= 0.5;
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qh_setdelaunay (dim+1, 1, point);
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facet= qh_findbestfacet (point, qh_ALL, &bestdist, &isoutside);
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FOREACHvertex_(facet->vertices) {
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for (k=0; k < dim; k++)
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printf ("%5.2f ", vertex->point[k]);
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printf ("\n");
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}
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} /*.findDelaunay.*/
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/*--------------------------------------------------
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-makehalf- set points to halfspaces for a (dim)-dimensional diamond
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points is numpoints X dim+1
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each halfspace consists of dim coefficients followed by an offset
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*/
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void makehalf (coordT *points, int numpoints, int dim) {
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int j,k;
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coordT *point;
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for (j=0; j<numpoints; j++) {
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point= points + j*(dim+1);
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point[dim]= -1.0; /* offset */
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for (k=dim; k--; ) {
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if (j & ( 1 << k))
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point[k]= 1.0;
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else
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point[k]= -1.0;
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}
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}
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} /*.makehalf.*/
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#define DIM 3 /* dimension of points, must be < 31 for SIZEcube */
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#define SIZEcube (1<<DIM)
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#define SIZEdiamond (2*DIM)
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#define TOTpoints (SIZEcube + SIZEdiamond)
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/*--------------------------------------------------
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-main- derived from call_qhull in user.c
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see program header
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this contains three runs of Qhull for convex hull, Delaunay
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triangulation or Voronoi vertices, and halfspace intersection
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*/
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int main (int argc, char *argv[]) {
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int dim= DIM; /* dimension of points */
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int numpoints; /* number of points */
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coordT points[(DIM+1)*TOTpoints]; /* array of coordinates for each point */
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coordT *rows[TOTpoints];
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boolT ismalloc= False; /* True if qhull should free points in qh_freeqhull() or reallocation */
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char flags[250]; /* option flags for qhull, see qh_opt.htm */
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FILE *outfile= stdout; /* output from qh_produce_output()
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use NULL to skip qh_produce_output() */
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FILE *errfile= stderr; /* error messages from qhull code */
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int exitcode; /* 0 if no error from qhull */
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facetT *facet; /* set by FORALLfacets */
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int curlong, totlong; /* memory remaining after qh_memfreeshort */
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int i;
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printf ("This is the output from user_eg.c\n\n\
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It shows how qhull() may be called from an application. It is not part\n\
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of qhull itself. If it appears accidently, please remove user_eg.c from\n\
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your project.\n\n");
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/*
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Run 1: convex hull
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*/
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printf( "\ncompute convex hull of cube after rotating input\n");
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sprintf (flags, "qhull s Tcv %s", argc >= 2 ? argv[1] : "");
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numpoints= SIZEcube;
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makecube (points, numpoints, DIM);
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for (i=numpoints; i--; )
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rows[i]= points+dim*i;
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qh_printmatrix (outfile, "input", rows, numpoints, dim);
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exitcode= qh_new_qhull (dim, numpoints, points, ismalloc,
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flags, outfile, errfile);
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if (!exitcode) { /* if no error */
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/* 'qh facet_list' contains the convex hull */
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print_summary();
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FORALLfacets {
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/* ... your code ... */
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}
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}
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qh_freeqhull(!qh_ALL); /* free long memory */
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qh_memfreeshort (&curlong, &totlong); /* free short memory and memory allocator */
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if (curlong || totlong)
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fprintf (errfile, "qhull internal warning (user_eg, #1): did not free %d bytes of long memory (%d pieces)\n", totlong, curlong);
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/*
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Run 2: Delaunay triangulation
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*/
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printf( "\ncompute 3-d Delaunay triangulation\n");
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sprintf (flags, "qhull s d Tcv %s", argc >= 3 ? argv[2] : "");
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numpoints= SIZEcube;
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makeDelaunay (points, numpoints, dim, time(NULL));
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for (i=numpoints; i--; )
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rows[i]= points+dim*i;
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qh_printmatrix (outfile, "input", rows, numpoints, dim);
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exitcode= qh_new_qhull (dim, numpoints, points, ismalloc,
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flags, outfile, errfile);
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if (!exitcode) { /* if no error */
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/* 'qh facet_list' contains the convex hull */
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/* If you want a Voronoi diagram ('v') and do not request output (i.e., outfile=NULL),
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call qh_setvoronoi_all() after qh_new_qhull(). */
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print_summary();
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FORALLfacets {
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/* ... your code ... */
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}
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printf( "\nfind 3-d Delaunay triangle closest to [0.5, 0.5, ...]\n");
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exitcode= setjmp (qh errexit);
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if (!exitcode) {
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/* Trap Qhull errors in findDelaunay(). Without the setjmp(), Qhull
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will exit() after reporting an error */
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qh NOerrexit= False;
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findDelaunay (DIM);
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}
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qh NOerrexit= True;
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}
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#if qh_QHpointer /* see user.h */
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{
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qhT *oldqhA, *oldqhB;
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coordT pointsB[DIM*TOTpoints]; /* array of coordinates for each point */
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printf( "\nsave first triangulation and compute a new triangulation\n");
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oldqhA= qh_save_qhull();
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sprintf (flags, "qhull s d Tcv %s", argc >= 3 ? argv[2] : "");
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numpoints= SIZEcube;
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makeDelaunay (pointsB, numpoints, dim, time(NULL)+1);
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for (i=numpoints; i--; )
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rows[i]= pointsB+dim*i;
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qh_printmatrix (outfile, "input", rows, numpoints, dim);
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exitcode= qh_new_qhull (dim, numpoints, pointsB, ismalloc,
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flags, outfile, errfile);
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if (!exitcode)
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print_summary();
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printf( "\nsave second triangulation and restore first one\n");
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oldqhB= qh_save_qhull();
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qh_restore_qhull (&oldqhA);
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print_summary();
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printf( "\nfree first triangulation and restore second one.\n");
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qh_freeqhull (qh_ALL); /* free short and long memory used by first call */
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/* do not use qh_memfreeshort */
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qh_restore_qhull (&oldqhB);
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print_summary();
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}
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#endif
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qh_freeqhull(!qh_ALL); /* free long memory */
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qh_memfreeshort (&curlong, &totlong); /* free short memory and memory allocator */
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if (curlong || totlong)
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fprintf (errfile, "qhull internal warning (user_eg, #2): did not free %d bytes of long memory (%d pieces)\n", totlong, curlong);
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/*
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Run 3: halfspace intersection about the origin
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*/
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printf( "\ncompute halfspace intersection about the origin for a diamond\n");
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sprintf (flags, "qhull H0 s Tcv %s", argc >= 4 ? argv[3] : "Fp");
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numpoints= SIZEcube;
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makehalf (points, numpoints, dim);
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for (i=numpoints; i--; )
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rows[i]= points+(dim+1)*i;
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qh_printmatrix (outfile, "input as halfspace coefficients + offsets", rows, numpoints, dim+1);
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/* use qh_sethalfspace_all to transform the halfspaces yourself.
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If so, set 'qh feasible_point and do not use option 'Hn,...' [it would retransform the halfspaces]
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*/
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exitcode= qh_new_qhull (dim+1, numpoints, points, ismalloc,
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flags, outfile, errfile);
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if (!exitcode)
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print_summary();
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qh_freeqhull (!qh_ALL);
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qh_memfreeshort (&curlong, &totlong);
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if (curlong || totlong) /* could also check previous runs */
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fprintf (stderr, "qhull internal warning (user_eg, #3): did not free %d bytes of long memory (%d pieces)\n",
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totlong, curlong);
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return exitcode;
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} /* main */
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