/************************************************************************* * Copyright (C) 2010-2014 Tavian Barnes * * * * 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 * * . * *************************************************************************/ /** * @file * Planes. */ #include "dimension.h" #include #include /** Plane type. */ typedef struct { dmnsn_object object; dmnsn_vector normal; } dmnsn_plane; /* Plane object callbacks */ static bool dmnsn_plane_intersection_fn(const dmnsn_object *plane, dmnsn_line line, dmnsn_intersection *intersection); static bool dmnsn_plane_inside_fn(const dmnsn_object *plane, dmnsn_vector point); /* Allocate a new plane */ dmnsn_object * dmnsn_new_plane(dmnsn_pool *pool, dmnsn_vector normal) { dmnsn_plane *plane = DMNSN_PALLOC(pool, dmnsn_plane); plane->normal = normal; dmnsn_object *object = &plane->object; dmnsn_init_object(object); object->intersection_fn = dmnsn_plane_intersection_fn; object->inside_fn = dmnsn_plane_inside_fn; object->bounding_box = dmnsn_infinite_bounding_box(); return object; } /* Returns the closest intersection of `line' with `plane' */ static bool dmnsn_plane_intersection_fn(const dmnsn_object *object, dmnsn_line line, dmnsn_intersection *intersection) { const dmnsn_plane *plane = (const dmnsn_plane *)object; dmnsn_vector normal = plane->normal; double den = dmnsn_vector_dot(line.n, normal); if (den != 0.0) { double t = -dmnsn_vector_dot(line.x0, normal)/den; if (t >= 0.0) { intersection->t = t; intersection->normal = normal; return true; } } return false; } /* Return whether a point is inside a plane */ static bool dmnsn_plane_inside_fn(const dmnsn_object *object, dmnsn_vector point) { const dmnsn_plane *plane = (const dmnsn_plane *)object; return dmnsn_vector_dot(point, plane->normal) < 0.0; }