aabb_ray.h

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/*                      A A B B _ R A Y . H
 * BRL-CAD
 *
 * Copyright (c) 2004-2026 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
 * version 2.1 as published by the Free Software Foundation.
 *
 * 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
 * Lesser 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.
 */
 
/*----------------------------------------------------------------------*/
/* @file aabb_ray.h */
/** @addtogroup bg_aabb_ray */
/** @{ */
 
/**
 * @brief
 *
 * Intersection between an infinite line and an axis-aligned box.
 *
 */
 
#ifndef BG_AABB_RAY_H
#define BG_AABB_RAY_H
 
#include "common.h"
#include "vmath.h"
#include "bg/defines.h"
 
__BEGIN_DECLS
 
/**
 * Compute the inverse direction components for use with
 * bg_isect_aabb_ray().  Components within SQRT_SMALL_FASTF of zero are
 * represented by INFINITY.  The input direction is not modified.
 */
BG_EXPORT extern void
bg_ray_invdir(vect_t *invdir, const vect_t dir);
 
/**
 * Test the infinite line defined by opt and the reciprocal direction vector
 * invdir against an axis-aligned bounding box.  Despite its historical name,
 * this function does not reject intersections behind opt: a successful result
 * can have both output parameters negative.  Callers that require a forward
 * ray must additionally require *r_max >= 0.0.
 *
 * On success, r_min and r_max are the entry and exit line parameters.  They
 * are valid only when the function returns 1.
 */
BG_EXPORT extern int
bg_isect_aabb_ray(
        fastf_t *r_min,
        fastf_t *r_max,
        const point_t opt,
        const fastf_t *invdir,
        const fastf_t *aabb_min,
        const fastf_t *aabb_max
        );
 
__END_DECLS
 
#endif  /* BG_AABB_RAY_H */
/** @} */
/*
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 * mode: C
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 * c-file-style: "stroustrup"
 * End:
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 */