dungeon_crawler

annotate prototype/vmath/vmath.inl @ 80:a373b36ffc17

better
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 27 Oct 2012 01:59:39 +0300
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nuclear@1 1 /*
nuclear@1 2 libvmath - a vector math library
nuclear@1 3 Copyright (C) 2004-2011 John Tsiombikas <nuclear@member.fsf.org>
nuclear@1 4
nuclear@1 5 This program is free software: you can redistribute it and/or modify
nuclear@1 6 it under the terms of the GNU Lesser General Public License as published
nuclear@1 7 by the Free Software Foundation, either version 3 of the License, or
nuclear@1 8 (at your option) any later version.
nuclear@1 9
nuclear@1 10 This program is distributed in the hope that it will be useful,
nuclear@1 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@1 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@1 13 GNU Lesser General Public License for more details.
nuclear@1 14
nuclear@1 15 You should have received a copy of the GNU Lesser General Public License
nuclear@1 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@1 17 */
nuclear@1 18
nuclear@1 19 #include <stdlib.h>
nuclear@1 20
nuclear@1 21 /** Generates a random number in [0, range) */
nuclear@1 22 static inline scalar_t frand(scalar_t range)
nuclear@1 23 {
nuclear@1 24 return range * (scalar_t)rand() / (scalar_t)RAND_MAX;
nuclear@1 25 }
nuclear@1 26
nuclear@1 27 /** Generates a random vector on the surface of a sphere */
nuclear@1 28 static inline vec3_t sphrand(scalar_t rad)
nuclear@1 29 {
nuclear@1 30 scalar_t u = (scalar_t)rand() / RAND_MAX;
nuclear@1 31 scalar_t v = (scalar_t)rand() / RAND_MAX;
nuclear@1 32
nuclear@1 33 scalar_t theta = 2.0 * M_PI * u;
nuclear@1 34 scalar_t phi = acos(2.0 * v - 1.0);
nuclear@1 35
nuclear@1 36 vec3_t res;
nuclear@1 37 res.x = rad * cos(theta) * sin(phi);
nuclear@1 38 res.y = rad * sin(theta) * sin(phi);
nuclear@1 39 res.z = rad * cos(phi);
nuclear@1 40 return res;
nuclear@1 41 }
nuclear@1 42
nuclear@1 43 /** linear interpolation */
nuclear@1 44 static inline scalar_t lerp(scalar_t a, scalar_t b, scalar_t t)
nuclear@1 45 {
nuclear@1 46 return a + (b - a) * t;
nuclear@1 47 }