3 * Routines to handle random number generation and hide platform differences.
6 // Written by Curtis Olson, started July 1997.
8 // Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt
10 // This library is free software; you can redistribute it and/or
11 // modify it under the terms of the GNU Library General Public
12 // License as published by the Free Software Foundation; either
13 // version 2 of the License, or (at your option) any later version.
15 // This library is distributed in the hope that it will be useful,
16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 // Library General Public License for more details.
20 // You should have received a copy of the GNU General Public License
21 // along with this program; if not, write to the Free Software
22 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
40 * Structure to hold MT algorithm state to easily allow independant
41 * sets of random numbers with different seeds.
43 struct {unsigned int array[MT_N]; int index; } typedef mt;
46 * Initialize a new MT state with a given seed.
48 void mt_init(mt *mt, unsigned int seed);
51 * Generate a new 32-bit random number based on the given MT state.
53 unsigned int mt_rand32( mt *mt);
56 * Generate a new random number between [0.0, 1.0) based
57 * on the given MT state.
59 double mt_rand(mt *mt);
62 * Seed the random number generater with time() so we don't see the
63 * same sequence every time.
65 void sg_srandom_time();
68 * Seed the random number generater with time() in 10 minute intervals
69 * so we get the same sequence within 10 minutes interval.
70 * This is useful for synchronizing two display systems.
72 void sg_srandom_time_10();
75 * Seed the random number generater with your own seed so can set up
76 * repeatable randomization.
77 * @param seed random number generator seed
79 void sg_srandom(unsigned int seed );
82 * Return a random number between [0.0, 1.0)
83 * @return next "random" number in the "random" sequence
93 #endif // _SG_RANDOM_H