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@@ -27,112 +27,111 @@
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* Warning: DO NOT enable this unless you understand what it does
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**************/
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//#define RANDOM_DEBUG
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/**
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* Structure to encapsulate the pseudo random number generators.
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*/
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struct Randomizer {
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/** The state of the randomizer */
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uint32 state[2];
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/**
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* Generate the next pseudo random number
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* @return the random number
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*/
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uint32 Next();
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/**
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* Generate the next pseudo random number scaled to max
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* @param max the maximum value of the returned random number
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* @return the random number
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*/
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uint32 Next(uint16 max);
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uint32 Next(uint32 max);
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/**
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* (Re)set the state of the random number generator.
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* @param seed the new state
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*/
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void SetSeed(uint32 seed);
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};
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extern Randomizer _random; ///< Random used in the game state calculations
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extern Randomizer _interactive_random; ///< Random used every else where is does not (directly) influence the game state
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/** Stores the state of all random number generators */
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struct SavedRandomSeeds {
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Randomizer random;
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Randomizer interactive_random;
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};
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/** Saves the current seeds
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* @param storage Storage for saving
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*/
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static inline void SaveRandomSeeds(SavedRandomSeeds *storage)
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{
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storage->random = _random;
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storage->interactive_random = _interactive_random;
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}
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/** Restores previously saved seeds
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* @param storage Storage where SaveRandomSeeds() stored th seeds
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*/
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static inline void RestoreRandomSeeds(const SavedRandomSeeds &storage)
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{
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_random = storage.random;
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_interactive_random = storage.interactive_random;
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}
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void SetRandomSeed(uint32 seed);
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#ifdef RANDOM_DEBUG
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#ifdef __APPLE__
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#define OTTD_Random() DoRandom(__LINE__, __FILE__)
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#else
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#define Random() DoRandom(__LINE__, __FILE__)
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#endif
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uint32 DoRandom(int line, const char *file);
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#define RandomRange(max) DoRandomRange(max, __LINE__, __FILE__)
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uint DoRandomRange(uint max, int line, const char *file);
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uint32 DoRandomRange(uint32 max, int line, const char *file);
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#else
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static FORCEINLINE uint32 Random()
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{
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return _random.Next();
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}
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static FORCEINLINE uint32 RandomRange(uint max)
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static FORCEINLINE uint32 RandomRange(uint32 max)
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{
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assert(max <= UINT16_MAX);
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return _random.Next(max);
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}
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#endif
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static FORCEINLINE uint32 InteractiveRandom()
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{
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return _interactive_random.Next();
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}
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static FORCEINLINE uint32 InteractiveRandomRange(uint16 max)
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static FORCEINLINE uint32 InteractiveRandomRange(uint32 max)
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{
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return _interactive_random.Next(max);
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}
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/**
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* Checks if a given randomize-number is below a given probability.
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*
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* This function is used to check if the given probability by the fraction of (a/b)
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* is greater than low 16 bits of the given randomize-number r.
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*
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* Do not use this function twice on the same random 16 bits as it will yield
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* the same result. One can use a random number for two calls to Chance16I,
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* where one call sends the low 16 bits and the other the high 16 bits.
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*
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* @param a The numerator of the fraction
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* @param b The denominator of the fraction, must of course not be null
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* @param r The given randomize-number
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* @return True if the probability given by r is less or equal to (a/b)
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*/
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static FORCEINLINE bool Chance16I(const uint a, const uint b, const uint32 r)
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{
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assert(b != 0);
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return (((uint16)r * b + b / 2) >> 16) < a;
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}
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