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/*************************************************************************
* Copyright (C) 2009-2014 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
* Cubes.
*/
#include "internal.h"
#include "dimension/model.h"
#include <math.h>
/// Intersection callback for a cube.
static bool
dmnsn_cube_intersection_fn(const dmnsn_object *cube, dmnsn_ray ray,
dmnsn_intersection *intersection)
{
// Clip the given ray against the X, Y, and Z slabs
dmnsn_vector nmin, nmax;
double tmin, tmax;
double tx1 = (-1.0 - ray.x0.X)/ray.n.X;
double tx2 = (+1.0 - ray.x0.X)/ray.n.X;
if (tx1 < tx2) {
tmin = tx1;
tmax = tx2;
nmin = dmnsn_new_vector(-1.0, 0.0, 0.0);
nmax = dmnsn_new_vector(+1.0, 0.0, 0.0);
} else {
tmin = tx2;
tmax = tx1;
nmin = dmnsn_new_vector(+1.0, 0.0, 0.0);
nmax = dmnsn_new_vector(-1.0, 0.0, 0.0);
}
if (tmin > tmax)
return false;
double ty1 = (-1.0 - ray.x0.Y)/ray.n.Y;
double ty2 = (+1.0 - ray.x0.Y)/ray.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;
double tz1 = (-1.0 - ray.x0.Z)/ray.n.Z;
double tz2 = (+1.0 - ray.x0.Z)/ray.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;
if (tmin < 0.0) {
tmin = tmax;
nmin = nmax;
}
if (tmin >= 0.0) {
intersection->t = tmin;
intersection->normal = nmin;
return true;
} else {
return false;
}
}
/// 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;
}
/// Boundary callback for a cube.
static dmnsn_aabb
dmnsn_cube_bounding_fn(const dmnsn_object *object, dmnsn_matrix trans)
{
dmnsn_aabb box = dmnsn_symmetric_aabb(dmnsn_new_vector(1.0, 1.0, 1.0));
return dmnsn_transform_aabb(trans, box);
}
/// Cube vtable.
static const dmnsn_object_vtable dmnsn_cube_vtable = {
.intersection_fn = dmnsn_cube_intersection_fn,
.inside_fn = dmnsn_cube_inside_fn,
.bounding_fn = dmnsn_cube_bounding_fn,
};
// Allocate a new cube object
dmnsn_object *
dmnsn_new_cube(dmnsn_pool *pool)
{
dmnsn_object *cube = dmnsn_new_object(pool);
cube->vtable = &dmnsn_cube_vtable;
return cube;
}
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