nurb_example.c

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/*                  N U R B _ E X A M P L E . C
 * BRL-CAD
 *
 * Copyright (c) 2004-2006 United States Government as represented by
 * the U.S. Army Research Laboratory.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this file; see the file named COPYING for more
 * information.
 */

/** @addtogroup nurb */

/*@{*/
/** @file nurb_example.c
 *
 *  Author -
 *      Paul R. Stay
 *
 *  Source -
 *      The U. S. Army Research Laboratory
 *      Aberdeen Proving Ground, Maryland  21005-5068  USA
 *
 */
/*@}*/

#ifndef lint
static const char RCSid[] = "@(#)$Header: /cvsroot/brlcad/brlcad/src/librt/nurb_example.c,v 14.11 2006/09/16 02:04:25 lbutler Exp $ (ARL)";
#endif

#include "common.h"

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "machine.h"
#include "vmath.h"
#include "raytrace.h"
#include "nurb.h"
#include "plot3.h"


fastf_t grid[10][10][3];
fastf_t ngrid[10][10][3];


/* Interpoate the data using b-splines */
void
interpolate_data()
{
        struct face_g_snurb srf;
        struct face_g_snurb *srf2, *srf3;
        struct knot_vector new_kv;

        rt_nurb_sinterp( &srf, 4, (const fastf_t *)grid, 10, 10 );

#if 0
        /* Draw control mesh in blue */
        pl_color( stdout, 145, 145, 255 );
        rt_nurb_plot_snurb( stdout, &srf );
#endif

#if 0
        rt_nurb_reverse_srf( &srf );
        rt_nurb_kvnorm( &srf.u );
        rt_nurb_kvnorm( &srf.v );
#endif

        /* lets take a look at it.  Refine to 100 points in both directions. */
        rt_nurb_kvknot( &new_kv, srf.order[0], 0.0, 1.0, 100, (struct resource *)NULL);
        srf2 = (struct face_g_snurb *) rt_nurb_s_refine( &srf, 0, &new_kv, (struct resource *)NULL);
        srf3 = (struct face_g_snurb *) rt_nurb_s_refine( srf2, 1, &new_kv, (struct resource *)NULL);

        /* Draw refined mesh in yellow */
        pl_color( stdout, 200, 200, 50 );
        rt_nurb_plot_snurb( stdout, srf3 );
}

int main(int argc, char *argv[])
{

        fastf_t hscale;
        fastf_t v;
        int i, j;

        hscale = 2.5;

        /* generate a 10 x 10 grid of random height data */

        pl_color(stdout,155, 55, 55);

        for( i = 0; i < 10; i++)
                for( j = 0; j < 10; j++)
                {
                        v = hscale * drand48() + 10.0;
                        grid[i][j][0] = i;
                        grid[i][j][1] = j;
                        grid[i][j][2] = v;

                        pd_3move( stdout,
                            grid[i][j][0],  grid[i][j][1], grid[i][j][2] - .14);
                        pd_3cont( stdout,
                            grid[i][j][0], grid[i][j][1], grid[i][j][2] + .14);

                        pd_3move( stdout,
                            grid[i][j][0] - .14, grid[i][j][1], grid[i][j][2]);
                        pd_3cont( stdout,
                            grid[i][j][0] + .14, grid[i][j][1], grid[i][j][2] );

                        pd_3move( stdout,
                            grid[i][j][0], grid[i][j][1]-.14, grid[i][j][2]);
                        pd_3cont( stdout,
                            grid[i][j][0], grid[i][j][1]+.14, grid[i][j][2]);
                }

        interpolate_data();
}

/*
 * Local Variables:
 * mode: C
 * tab-width: 8
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 * ex: shiftwidth=4 tabstop=8
 */

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