nurb_reverse.c

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/*                  N U R B _ R E V E R S E . C
 * BRL-CAD
 *
 * Copyright (c) 1991-2006 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_reverse.c
 *      Reverse the direction of a nurb surface
 *      by transposing the control points
 *
 *  Author -
 *      Paul R. Stay
 *
 *  Source -
 *     SECAD/VLD Computing Consortium, Bldg 394
 *     The U.S. Army Ballistic Research Laboratory
 *     Aberdeen Proving Ground, Maryland 21005
 *
 */
/*@}*/

#include "common.h"



#include <stdio.h>
#include "machine.h"
#include "vmath.h"
#include "nmg.h"
#include "raytrace.h"
#include "nurb.h"

void
rt_nurb_reverse_srf(struct face_g_snurb *srf)
{

        int i,j,k;
        int coords;
        int row, col;
        fastf_t * p_ptr;
        fastf_t * tmp;
        fastf_t * ptr2;

        p_ptr = srf->ctl_points;
        coords = RT_NURB_EXTRACT_COORDS(srf->pt_type);

        row = srf->s_size[0];
        col = srf->s_size[1];

        tmp = (fastf_t *) bu_malloc(sizeof(fastf_t) * coords *
                row * col, "nurb_reverse:temp");

        ptr2 = tmp;

        for(i = 0; i < row; i++)
        for(j = 0; j < col; j++)
        {
                for( k = 0; k < coords; k++)
                       *ptr2++ = srf->ctl_points[ (j * col + i) * coords + k];
        }

        for( i = 0; i < row * col * coords; i++)
                p_ptr[i] = tmp[i];

        srf->s_size[0] = col;
        srf->s_size[1] = row;

        i = srf->u.k_size;
        srf->u.k_size = srf->v.k_size;
        srf->v.k_size = i;

        p_ptr = srf->u.knots;
        srf->u.knots = srf->v.knots;
        srf->v.knots = p_ptr;

        bu_free((char *) tmp, "temporary storage for transpose");
}

/*
 * 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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