From 3ec26ddd28cbcc279a4fa65de8d68c68b3950576 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Wed, 13 Jul 2011 13:47:17 -0600 Subject: Implement triangles. --- libdimension/triangle.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 libdimension/triangle.c (limited to 'libdimension/triangle.c') diff --git a/libdimension/triangle.c b/libdimension/triangle.c new file mode 100644 index 0000000..bd54e1a --- /dev/null +++ b/libdimension/triangle.c @@ -0,0 +1,83 @@ +/************************************************************************* + * Copyright (C) 2009-2010 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 + * Triangles. + */ + +#include "dimension.h" + +typedef struct dmnsn_triangle_payload { + dmnsn_vector a, ab, ac, normal; +} dmnsn_triangle_payload; + +/** Triangle intersection callback. */ +static bool +dmnsn_triangle_intersection_fn(const dmnsn_object *triangle, dmnsn_line l, + dmnsn_intersection *intersection) +{ + const dmnsn_triangle_payload *payload = triangle->ptr; + + double den = -dmnsn_vector_dot(l.n, payload->normal); + dmnsn_vector ax0 = dmnsn_vector_sub(l.x0, payload->a); + double t = dmnsn_vector_dot(ax0, payload->normal)/den; + double u = -dmnsn_vector_dot(l.n, dmnsn_vector_cross(ax0, payload->ac))/den; + double v = -dmnsn_vector_dot(l.n, dmnsn_vector_cross(payload->ab, ax0))/den; + if (t >= 0.0 && u >= 0.0 && v >= 0.0 && u + v <= 1.0) { + intersection->ray = l; + intersection->t = t; + intersection->normal = payload->normal; + intersection->texture = triangle->texture; + intersection->interior = triangle->interior; + return true; + } + + return false; +} + +/** Triangle inside callback. */ +static bool +dmnsn_triangle_inside_fn(const dmnsn_object *triangle, dmnsn_vector point) +{ + return false; +} + +/* Allocate a new triangle */ +dmnsn_object * +dmnsn_new_triangle(dmnsn_vector a, dmnsn_vector b, dmnsn_vector c) +{ + dmnsn_object *triangle = dmnsn_new_object(); + + dmnsn_triangle_payload *payload = + dmnsn_malloc(sizeof(dmnsn_triangle_payload)); + payload->a = a; + payload->ab = dmnsn_vector_sub(b, a); + payload->ac = dmnsn_vector_sub(c, a); + payload->normal = dmnsn_vector_cross(payload->ab, payload->ac); + + triangle->ptr = payload; + triangle->intersection_fn = dmnsn_triangle_intersection_fn; + triangle->inside_fn = dmnsn_triangle_inside_fn; + triangle->free_fn = dmnsn_free; + triangle->bounding_box.min = dmnsn_vector_min(dmnsn_vector_min(a, b), c); + triangle->bounding_box.max = dmnsn_vector_max(dmnsn_vector_max(a, b), c); + return triangle; +} -- cgit v1.2.3