nurb_trim_util.c

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/*                N U R B _ T R I M _ U T I L . C
 * BRL-CAD
 *
 * Copyright (c) 1990-2006 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_trim_util.c
 * Trimming curve Utilities.
 *
 * Author:  Paul R. Stay
 * Source
 *      SECAD/VLD Computing Consortium, Bldg 394
 *      The US Army Ballistic Research Laboratory
 *      Aberdeen Proving Ground, Maryland 21005
 *
 * Date: Mon July 3, 1995
 */
/*@}*/

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

#include "common.h"



#include <stdio.h>
#include <math.h>

#include "machine.h"
#include "vmath.h"
#include "raytrace.h"
#include "nurb.h"

/* Check to see if the curve conmtrol polygon
 * wonders outside the parametric range given.
 * This is usefull if a trimming curve control polygon is outside
 * but the evaluated curve is not. We will want to refine the
 * curve so that is lies within the range;
 * otherwise it breaks the surface evaluation
 */

int
rt_nurb_crv_in_range(struct edge_g_cnurb *crv, fastf_t u_min, fastf_t u_max, fastf_t v_min, fastf_t v_max)
{
        point_t eval;
        fastf_t *pts;
        int     coords = RT_NURB_EXTRACT_COORDS( crv->pt_type );
        int     rat = RT_NURB_IS_PT_RATIONAL(crv->pt_type);
        int     i;

        pts = &crv->ctl_points[0];

        for( i = 0; i < crv->c_size; i++)
        {
                if (rat)
                {
                        eval[0] = pts[0] / pts[2];
                        eval[1] = pts[1] / pts[2];
                        eval[2] = 1;
                } else  {
                        eval[0] = pts[0];
                        eval[1] = pts[1];
                        eval[2] = 1;
                }

                if( eval[0] < u_min || eval[0] > u_max )
                        return 0;

                if( eval[1] < v_min || eval[1] > v_max )
                        return 0;

                pts += coords;
        }
        return 1;
}

/*
 * 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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