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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>
/*
* Cube
*/
/* Cube callbacks */
static bool dmnsn_cube_intersection_fn(const dmnsn_object *cube,
dmnsn_line line,
dmnsn_intersection *intersection);
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 bool
dmnsn_cube_intersection_fn(const dmnsn_object *cube, dmnsn_line line,
dmnsn_intersection *intersection)
{
/* Clip the given line against the X, Y, and Z slabs */
dmnsn_line line_trans = dmnsn_transform_line(cube->trans_inv, line);
dmnsn_vector nmin, nmax;
double tmin = -INFINITY, tmax = INFINITY;
if (line_trans.n.x != 0.0) {
double tx1 = (-1.0 - line_trans.x0.x)/line_trans.n.x;
double tx2 = (+1.0 - line_trans.x0.x)/line_trans.n.x;
if (tx1 < tx2) {
if (tx1 > tmin) {
tmin = tx1;
nmin = dmnsn_new_vector(-1.0, 0.0, 0.0);
}
if (tx2 < tmax) {
tmax = tx2;
nmax = dmnsn_new_vector(+1.0, 0.0, 0.0);
}
} else {
if (tx2 > tmin) {
tmin = tx2;
nmin = dmnsn_new_vector(+1.0, 0.0, 0.0);
}
if (tx1 < tmax) {
tmax = tx1;
nmax = dmnsn_new_vector(-1.0, 0.0, 0.0);
}
}
if (tmin > tmax)
return false;
} else {
if (line_trans.x0.x < -1.0 || line_trans.x0.x > 1.0)
return false;
}
if (line_trans.n.y != 0.0) {
double ty1 = (-1.0 - line_trans.x0.y)/line_trans.n.y;
double ty2 = (+1.0 - line_trans.x0.y)/line_trans.n.y;
if (ty1 < ty2) {
if (ty1 > tmin) {
tmin = ty1;
nmin = dmnsn_new_vector(0.0, -1.0, 0.0);
}
if (ty2 < tmax) {
tmax = ty2;
nmax = dmnsn_new_vector(0.0, +1.0, 0.0);
}
} else {
if (ty2 > tmin) {
tmin = ty2;
nmin = dmnsn_new_vector(0.0, +1.0, 0.0);
}
if (ty1 < tmax) {
tmax = ty1;
nmax = dmnsn_new_vector(0.0, -1.0, 0.0);
}
}
if (tmin > tmax)
return false;
} else {
if (line_trans.x0.y < -1.0 || line_trans.x0.y > 1.0)
return false;
}
if (line_trans.n.z != 0.0) {
double tz1 = (-1.0 - line_trans.x0.z)/line_trans.n.z;
double tz2 = (+1.0 - line_trans.x0.z)/line_trans.n.z;
if (tz1 < tz2) {
if (tz1 > tmin) {
tmin = tz1;
nmin = dmnsn_new_vector(0.0, 0.0, -1.0);
}
if (tz2 < tmax) {
tmax = tz2;
nmax = dmnsn_new_vector(0.0, 0.0, +1.0);
}
} else {
if (tz2 > tmin) {
tmin = tz2;
nmin = dmnsn_new_vector(0.0, 0.0, +1.0);
}
if (tz1 < tmax) {
tmax = tz1;
nmax = dmnsn_new_vector(0.0, 0.0, -1.0);
}
}
if (tmin > tmax)
return false;
} else {
if (line_trans.x0.z < -1.0 || line_trans.x0.z > 1.0)
return false;
}
if (tmin < 0.0) {
tmin = tmax;
nmin = nmax;
}
if (tmin >= 0.0) {
intersection->ray = line;
intersection->t = tmin;
intersection->normal = dmnsn_transform_normal(cube->trans, nmin);
intersection->texture = cube->texture;
intersection->interior = cube->interior;
return true;
} else {
return false;
}
}
/* Inside callback for a cube */
static bool
dmnsn_cube_inside_fn(const dmnsn_object *cube, dmnsn_vector point)
{
point = dmnsn_transform_vector(cube->trans_inv, 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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