Files
@ r18112:64cad0abf83a
Branch filter:
Location: cpp/openttd-patchpack/source/src/core/random_func.hpp
r18112:64cad0abf83a
5.0 KiB
text/x-c++hdr
(svn r22947) -Fix: [NewGRF] Do not call CB 32 for disaster, effect vehicles or aircraft shadows/rotors.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 | /* $Id$ */
/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD 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 General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file random_func.hpp Pseudo random number generator. */
#ifndef RANDOM_FUNC_HPP
#define RANDOM_FUNC_HPP
#if defined(__APPLE__)
/* Apple already has Random declared */
#define Random OTTD_Random
#endif /* __APPLE__ */
/**************
* Warning: DO NOT enable this unless you understand what it does
*
* If enabled, in a network game all randoms will be dumped to the
* stdout if the first client joins (or if you are a client). This
* is to help finding desync problems.
*
* Warning: DO NOT enable this unless you understand what it does
**************/
//#define RANDOM_DEBUG
/**
* Structure to encapsulate the pseudo random number generators.
*/
struct Randomizer {
/** The state of the randomizer */
uint32 state[2];
uint32 Next();
uint32 Next(uint32 max);
void SetSeed(uint32 seed);
};
extern Randomizer _random; ///< Random used in the game state calculations
extern Randomizer _interactive_random; ///< Random used every else where is does not (directly) influence the game state
/** Stores the state of all random number generators */
struct SavedRandomSeeds {
Randomizer random;
Randomizer interactive_random;
};
/**
* Saves the current seeds
* @param storage Storage for saving
*/
static inline void SaveRandomSeeds(SavedRandomSeeds *storage)
{
storage->random = _random;
storage->interactive_random = _interactive_random;
}
/**
* Restores previously saved seeds
* @param storage Storage where SaveRandomSeeds() stored th seeds
*/
static inline void RestoreRandomSeeds(const SavedRandomSeeds &storage)
{
_random = storage.random;
_interactive_random = storage.interactive_random;
}
void SetRandomSeed(uint32 seed);
#ifdef RANDOM_DEBUG
#ifdef __APPLE__
#define OTTD_Random() DoRandom(__LINE__, __FILE__)
#else
#define Random() DoRandom(__LINE__, __FILE__)
#endif
uint32 DoRandom(int line, const char *file);
#define RandomRange(max) DoRandomRange(max, __LINE__, __FILE__)
uint32 DoRandomRange(uint32 max, int line, const char *file);
#else
static FORCEINLINE uint32 Random()
{
return _random.Next();
}
static FORCEINLINE uint32 RandomRange(uint32 max)
{
return _random.Next(max);
}
#endif
static FORCEINLINE uint32 InteractiveRandom()
{
return _interactive_random.Next();
}
static FORCEINLINE uint32 InteractiveRandomRange(uint32 max)
{
return _interactive_random.Next(max);
}
/**
* Checks if a given randomize-number is below a given probability.
*
* This function is used to check if the given probability by the fraction of (a/b)
* is greater than low 16 bits of the given randomize-number r.
*
* Do not use this function twice on the same random 16 bits as it will yield
* the same result. One can use a random number for two calls to Chance16I,
* where one call sends the low 16 bits and the other the high 16 bits.
*
* @param a The numerator of the fraction
* @param b The denominator of the fraction, must of course not be null
* @param r The given randomize-number
* @return True if the probability given by r is less or equal to (a/b)
*/
static FORCEINLINE bool Chance16I(const uint a, const uint b, const uint32 r)
{
assert(b != 0);
return (((uint16)r * b + b / 2) >> 16) < a;
}
/**
* Flips a coin with given probability.
*
* This function returns true with (a/b) probability.
*
* @see Chance16I()
* @param a The nominator of the fraction
* @param b The denominator of the fraction
* @return True with (a/b) probability
*/
#ifdef RANDOM_DEBUG
#define Chance16(a, b) Chance16I(a, b, DoRandom(__LINE__, __FILE__))
#else
static FORCEINLINE bool Chance16(const uint a, const uint b)
{
return Chance16I(a, b, Random());
}
#endif /* RANDOM_DEBUG */
/**
* Flips a coin with a given probability and saves the randomize-number in a variable.
*
* This function uses the same parameters as Chance16. The third parameter
* must be a variable the randomize-number from Random() is saved in.
*
* The low 16 bits of r will already be used and can therefor not be passed to
* Chance16I. One can only send the high 16 bits to Chance16I.
*
* @see Chance16I()
* @param a The numerator of the fraction
* @param b The denominator of the fraction
* @param r The variable to save the randomize-number from Random()
* @return True in (a/b) percent
*/
#ifdef RANDOM_DEBUG
#define Chance16R(a, b, r) (r = DoRandom(__LINE__, __FILE__), Chance16I(a, b, r))
#else
static FORCEINLINE bool Chance16R(const uint a, const uint b, uint32 &r)
{
r = Random();
return Chance16I(a, b, r);
}
#endif /* RANDOM_DEBUG */
#endif /* RANDOM_FUNC_HPP */
|