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Diffstat (limited to 'libdimension/cube.c')
| -rw-r--r-- | libdimension/cube.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/libdimension/cube.c b/libdimension/cube.c new file mode 100644 index 0000000..197a0f8 --- /dev/null +++ b/libdimension/cube.c @@ -0,0 +1,113 @@ +/************************************************************************* + * Copyright (C) 2008 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 */ + +static dmnsn_array *dmnsn_cube_intersections_fn(const dmnsn_object *cube, + dmnsn_line line); +static int dmnsn_cube_inside_fn(const dmnsn_object *cube, + dmnsn_vector point); + +dmnsn_object * +dmnsn_new_cube() +{ + dmnsn_object *cube = dmnsn_new_object(); + if (cube) { + cube->intersections_fn = &dmnsn_cube_intersections_fn; + cube->inside_fn = &dmnsn_cube_inside_fn; + } + return cube; +} + +void +dmnsn_delete_cube(dmnsn_object *cube) +{ + dmnsn_delete_object(cube); +} + +static dmnsn_array * +dmnsn_cube_intersections_fn(const dmnsn_object *cube, dmnsn_line line) +{ + double t; + dmnsn_vector p; + dmnsn_array *array = dmnsn_new_array(sizeof(double)); + + /* Six ray-plane intersection tests (x, y, z) = +/- 1.0 */ + + if (line.n.x != 0.0) { + /* x = -1.0 */ + t = (-1.0 - line.x0.x)/line.n.x; + p = dmnsn_line_point(line, t); + if (p.y >= -1.0 && p.y <= 1.0 && p.z >= -1.0 && p.z <= 1.0) { + dmnsn_array_push(array, &t); + } + + /* x = 1.0 */ + t = (1.0 - line.x0.x)/line.n.x; + p = dmnsn_line_point(line, t); + if (p.y >= -1.0 && p.y <= 1.0 && p.z >= -1.0 && p.z <= 1.0) { + dmnsn_array_push(array, &t); + } + } + + if (line.n.y != 0.0) { + /* y = -1.0 */ + t = (-1.0 - line.x0.y)/line.n.y; + p = dmnsn_line_point(line, t); + if (p.x >= -1.0 && p.x <= 1.0 && p.z >= -1.0 && p.z <= 1.0) { + dmnsn_array_push(array, &t); + } + + /* y = 1.0 */ + t = (1.0 - line.x0.y)/line.n.y; + p = dmnsn_line_point(line, t); + if (p.x >= -1.0 && p.x <= 1.0 && p.z >= -1.0 && p.z <= 1.0) { + dmnsn_array_push(array, &t); + } + } + + if (line.n.z != 0.0) { + /* z = -1.0 */ + t = (-1.0 - line.x0.z)/line.n.z; + p = dmnsn_line_point(line, t); + if (p.x >= -1.0 && p.x <= 1.0 && p.y >= -1.0 && p.y <= 1.0) { + dmnsn_array_push(array, &t); + } + + /* z = 1.0 */ + t = (1.0 - line.x0.z)/line.n.z; + p = dmnsn_line_point(line, t); + if (p.x >= -1.0 && p.x <= 1.0 && p.y >= -1.0 && p.y <= 1.0) { + dmnsn_array_push(array, &t); + } + } + + return array; +} + +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; +} |