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/*************************************************************************
* Copyright (C) 2010 Tavian Barnes <tavianator@tavianator.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension 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 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension 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 program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
/**
* @file
* Planes.
*/
#include "dimension.h"
#include <math.h>
#include <stdlib.h>
/* Plane object callbacks */
static bool dmnsn_plane_intersection_fn(const dmnsn_object *plane,
dmnsn_line line,
dmnsn_intersection *intersection);
static bool dmnsn_plane_inside_fn(const dmnsn_object *plane,
dmnsn_vector point);
/* Allocate a new plane */
dmnsn_object *
dmnsn_new_plane(dmnsn_vector normal)
{
dmnsn_object *plane = dmnsn_new_object();
dmnsn_vector *param = dmnsn_malloc(sizeof(dmnsn_vector));
*param = normal;
plane->intersection_fn = &dmnsn_plane_intersection_fn;
plane->inside_fn = &dmnsn_plane_inside_fn;
plane->free_fn = &dmnsn_free;
plane->bounding_box = dmnsn_infinite_bounding_box();
plane->ptr = param;
return plane;
}
/* Returns the closest intersection of `line' with `plane' */
static bool
dmnsn_plane_intersection_fn(const dmnsn_object *plane, dmnsn_line line,
dmnsn_intersection *intersection)
{
dmnsn_vector *normal = plane->ptr;
double den = dmnsn_vector_dot(line.n, *normal);
if (den != 0.0) {
double t = -dmnsn_vector_dot(line.x0, *normal)/den;
if (t >= 0.0) {
intersection->ray = line;
intersection->t = t;
intersection->normal = *normal;
intersection->texture = plane->texture;
intersection->interior = plane->interior;
return true;
}
}
return false;
}
/* Return whether a point is inside a plane */
static bool
dmnsn_plane_inside_fn(const dmnsn_object *plane, dmnsn_vector point)
{
dmnsn_vector *normal = plane->ptr;
return dmnsn_vector_dot(point, *normal) < 0.0;
}
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