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/*************************************************************************
* Copyright (C) 2010 Tavian Barnes <tavianator@gmail.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/>. *
*************************************************************************/
#include "dimension.h"
#include <math.h> /* For sqrt */
/*
* Cube
*/
/* Cube callbacks */
static dmnsn_intersection *dmnsn_cube_intersection_fn(const dmnsn_object *cube,
dmnsn_line line);
static bool dmnsn_cube_inside_fn(const dmnsn_object *cube,
dmnsn_vector point);
/* Allocate a new cube object */
dmnsn_object *
dmnsn_new_cube()
{
dmnsn_object *cube = dmnsn_new_object();
cube->intersection_fn = &dmnsn_cube_intersection_fn;
cube->inside_fn = &dmnsn_cube_inside_fn;
cube->bounding_box.min = dmnsn_new_vector(-1.0, -1.0, -1.0);
cube->bounding_box.max = dmnsn_new_vector(1.0, 1.0, 1.0);
return cube;
}
/* Intersections callback for a cube */
static dmnsn_intersection *
dmnsn_cube_intersection_fn(const dmnsn_object *cube, dmnsn_line line)
{
double t = -1.0, t_temp;
dmnsn_vector p, normal;
dmnsn_intersection *intersection = NULL;
/* Six ray-plane intersection tests (x, y, z) = +/- 1.0 */
if (line.n.x != 0.0) {
/* x = -1.0 */
t_temp = (-1.0 - line.x0.x)/line.n.x;
p = dmnsn_line_point(line, t_temp);
if (p.y >= -1.0 && p.y <= 1.0 && p.z >= -1.0 && p.z <= 1.0
&& t_temp >= 0.0 && (t < 0.0 || t_temp < t))
{
t = t_temp;
normal = dmnsn_new_vector(-1.0, 0.0, 0.0);
}
/* x = 1.0 */
t_temp = (1.0 - line.x0.x)/line.n.x;
p = dmnsn_line_point(line, t_temp);
if (p.y >= -1.0 && p.y <= 1.0 && p.z >= -1.0 && p.z <= 1.0
&& t_temp >= 0.0 && (t < 0.0 || t_temp < t))
{
t = t_temp;
normal = dmnsn_new_vector(1.0, 0.0, 0.0);
}
}
if (line.n.y != 0.0) {
/* y = -1.0 */
t_temp = (-1.0 - line.x0.y)/line.n.y;
p = dmnsn_line_point(line, t_temp);
if (p.x >= -1.0 && p.x <= 1.0 && p.z >= -1.0 && p.z <= 1.0
&& t_temp >= 0.0 && (t < 0.0 || t_temp < t))
{
t = t_temp;
normal = dmnsn_new_vector(0.0, -1.0, 0.0);
}
/* y = 1.0 */
t_temp = (1.0 - line.x0.y)/line.n.y;
p = dmnsn_line_point(line, t_temp);
if (p.x >= -1.0 && p.x <= 1.0 && p.z >= -1.0 && p.z <= 1.0
&& t_temp >= 0.0 && (t < 0.0 || t_temp < t))
{
t = t_temp;
normal = dmnsn_new_vector(0.0, 1.0, 0.0);
}
}
if (line.n.z != 0.0) {
/* z = -1.0 */
t_temp = (-1.0 - line.x0.z)/line.n.z;
p = dmnsn_line_point(line, t_temp);
if (p.x >= -1.0 && p.x <= 1.0 && p.y >= -1.0 && p.y <= 1.0
&& t_temp >= 0.0 && (t < 0.0 || t_temp < t))
{
t = t_temp;
normal = dmnsn_new_vector(0.0, 0.0, -1.0);
}
/* z = 1.0 */
t_temp = (1.0 - line.x0.z)/line.n.z;
p = dmnsn_line_point(line, t_temp);
if (p.x >= -1.0 && p.x <= 1.0 && p.y >= -1.0 && p.y <= 1.0
&& t_temp >= 0.0 && (t < 0.0 || t_temp < t))
{
t = t_temp;
normal = dmnsn_new_vector(0.0, 0.0, 1.0);
}
}
if (t >= 0.0) {
intersection = dmnsn_new_intersection();
intersection->ray = line;
intersection->t = t;
intersection->normal = normal;
intersection->texture = cube->texture;
intersection->interior = cube->interior;
}
return intersection;
}
/* Inside callback for a cube */
static bool
dmnsn_cube_inside_fn(const dmnsn_object *cube, dmnsn_vector point)
{
return point.x > -1.0 && point.x < 1.0
&& point.y > -1.0 && point.y < 1.0
&& point.z > -1.0 && point.z < 1.0;
}
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