605125c0e7
In addition to Stuart's changes, there's an independent quad tree builder class for constructing loose quad trees from scene graph nodes. Stuart also implemented changes to the random number generator suggested by Andy Ross.
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/**
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* \file sg_random.h
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* Routines to handle random number generation and hide platform differences.
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*/
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// Written by Curtis Olson, started July 1997.
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//
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// Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// $Id$
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#ifndef _SG_RANDOM_H
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#define _SG_RANDOM_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define MT_N 624
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#define MT_M 397
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/**
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* Structure to hold MT algorithm state to easily allow independant
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* sets of random numbers with different seeds.
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*/
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struct {unsigned int array[MT_N]; int index; } typedef mt;
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/**
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* Initialize a new MT state with a given seed.
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*/
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void mt_init(mt *mt, unsigned int seed);
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/**
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* Generate a new 32-bit random number based on the given MT state.
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*/
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unsigned int mt_rand32( mt *mt);
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/**
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* Generate a new random number between [0.0, 1.0) based
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* on the given MT state.
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*/
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double mt_rand(mt *mt);
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/**
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* Seed the random number generater with time() so we don't see the
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* same sequence every time.
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*/
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void sg_srandom_time();
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/**
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* Seed the random number generater with time() in 10 minute intervals
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* so we get the same sequence within 10 minutes interval.
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* This is useful for synchronizing two display systems.
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*/
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void sg_srandom_time_10();
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/**
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* Seed the random number generater with your own seed so can set up
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* repeatable randomization.
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* @param seed random number generator seed
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*/
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void sg_srandom(unsigned int seed );
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/**
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* Return a random number between [0.0, 1.0)
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* @return next "random" number in the "random" sequence
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*/
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double sg_random();
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#ifdef __cplusplus
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}
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#endif
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#endif // _SG_RANDOM_H
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