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Diffstat (limited to 'libdimension/cube.c')
| -rw-r--r-- | libdimension/cube.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/libdimension/cube.c b/libdimension/cube.c new file mode 100644 index 0000000..57dd12b --- /dev/null +++ b/libdimension/cube.c @@ -0,0 +1,143 @@ +/************************************************************************* + * Copyright (C) 2009 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 <stdlib.h> /* For malloc */ +#include <math.h> /* For sqrt */ + +/* + * Cube + */ + +/* Cube callbacks */ +static dmnsn_intersection *dmnsn_cube_intersection_fn(const dmnsn_object *cube, + dmnsn_line line); +static int 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(); + if (cube) { + cube->intersection_fn = &dmnsn_cube_intersection_fn; + cube->inside_fn = &dmnsn_cube_inside_fn; + cube->min = dmnsn_new_vector(-1.0, -1.0, -1.0); + cube->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(-copysign(1.0, line.n.x), 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(-copysign(1.0, line.n.x), 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, -copysign(1.0, 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, -copysign(1.0, line.n.y), 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, -copysign(1.0, line.n.z)); + } + + /* 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, -copysign(1.0, line.n.z)); + } + } + + if (t >= 0.0) { + intersection = dmnsn_new_intersection(); + intersection->ray = line; + intersection->t = t; + intersection->normal = normal; + intersection->texture = cube->texture; + } + + return intersection; +} + +/* Inside callback for a cube */ +static int +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; +} |