diff options
Diffstat (limited to 'libdimension')
| -rw-r--r-- | libdimension/Makefile.am | 1 | ||||
| -rw-r--r-- | libdimension/cylinder.c | 93 | ||||
| -rw-r--r-- | libdimension/dimension/objects.h | 3 | ||||
| -rw-r--r-- | libdimension/sphere.c | 2 |
4 files changed, 98 insertions, 1 deletions
diff --git a/libdimension/Makefile.am b/libdimension/Makefile.am index 77d3285..e437659 100644 --- a/libdimension/Makefile.am +++ b/libdimension/Makefile.am @@ -55,6 +55,7 @@ libdimension_la_SOURCES = $(nobase_include_HEADERS) \ color.c \ cube.c \ csg.c \ + cylinder.c \ diffuse.c \ dimension-impl.h \ error.c \ diff --git a/libdimension/cylinder.c b/libdimension/cylinder.c new file mode 100644 index 0000000..fb9c12c --- /dev/null +++ b/libdimension/cylinder.c @@ -0,0 +1,93 @@ +/************************************************************************* + * Copyright (C) 2009-2010 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> + +/* + * Cylinder + */ + +/* Cylinder callbacks */ +static bool dmnsn_cylinder_intersection_fn(const dmnsn_object *cylinder, + dmnsn_line line, + dmnsn_intersection *intersection); +static bool dmnsn_cylinder_inside_fn(const dmnsn_object *cylinder, + dmnsn_vector point); + +/* Allocate a new cylinder object */ +dmnsn_object * +dmnsn_new_cylinder() +{ + dmnsn_object *cylinder = dmnsn_new_object(); + cylinder->intersection_fn = &dmnsn_cylinder_intersection_fn; + cylinder->inside_fn = &dmnsn_cylinder_inside_fn; + cylinder->bounding_box.min = dmnsn_new_vector(-1.0, -1.0, -1.0); + cylinder->bounding_box.max = dmnsn_new_vector(1.0, 1.0, 1.0); + return cylinder; +} + +/* Intersections callback for a cylinder */ +static bool +dmnsn_cylinder_intersection_fn(const dmnsn_object *cylinder, dmnsn_line line, + dmnsn_intersection *intersection) +{ + dmnsn_line l = dmnsn_transform_line(cylinder->trans_inv, line); + + /* Solve (x0 + nx*t)^2 + (z0 + nz*t)^2 == 1 */ + double a, b, c, t; + a = l.n.x*l.n.x + l.n.z*l.n.z; + b = 2.0*(l.n.x*l.x0.x + l.n.z*l.x0.z); + c = l.x0.x*l.x0.x + l.x0.z*l.x0.z - 1.0; + + + if (b*b - 4.0*a*c >= 0.0) { + t = (-b - sqrt(b*b - 4.0*a*c))/(2.0*a); + dmnsn_vector p = dmnsn_line_point(l, t); + + if (t < 0.0 || p.y <= -1.0 || p.y >= 1.0) { + t = (-b + sqrt(b*b - 4.0*a*c))/(2.0*a); + p = dmnsn_line_point(l, t); + + if (t < 0.0 || p.y <= -1.0 || p.y >= 1.0) + return false; + } + + p.y = 0; + + intersection->ray = line; + intersection->t = t; + intersection->normal = dmnsn_transform_normal(cylinder->trans, p); + intersection->texture = cylinder->texture; + intersection->interior = cylinder->interior; + return true; + } + + return false; +} + +/* Inside callback for a cylinder */ +static bool +dmnsn_cylinder_inside_fn(const dmnsn_object *cylinder, dmnsn_vector point) +{ + point = dmnsn_transform_vector(cylinder->trans_inv, point); + return point.x*point.x + point.z*point.z < 1 + && point.y > -1.0 && point.y < 1.0; +} diff --git a/libdimension/dimension/objects.h b/libdimension/dimension/objects.h index 9986717..4db161c 100644 --- a/libdimension/dimension/objects.h +++ b/libdimension/dimension/objects.h @@ -34,4 +34,7 @@ dmnsn_object *dmnsn_new_sphere(void); /* A cube, axis-aligned, from (-1, -1, -1) to (1, 1, 1) */ dmnsn_object *dmnsn_new_cube(void); +/* A cylinder, of radius 1, from y = -1 to y = 1 */ +dmnsn_object *dmnsn_new_cylinder(void); + #endif /* DIMENSION_OBJECTS_H */ diff --git a/libdimension/sphere.c b/libdimension/sphere.c index a3ecf2d..98be4b5 100644 --- a/libdimension/sphere.c +++ b/libdimension/sphere.c @@ -51,7 +51,7 @@ dmnsn_sphere_intersection_fn(const dmnsn_object *sphere, dmnsn_line line, dmnsn_intersection *intersection) { dmnsn_line l = dmnsn_transform_line(sphere->trans_inv, line); - + /* Solve (x0 + nx*t)^2 + (y0 + ny*t)^2 + (z0 + nz*t)^2 == 1 */ double a, b, c, t; a = dmnsn_vector_dot(l.n, l.n); |