_ak_rng_8h_source

Wwise SDK 2022.1.18

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 released in source code form as part of the SDK installer package.
  
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 #pragma once
  
 #include <AK/SoundEngine/Common/AkTypes.h>
  
 /// A pseudorandom number generator appropriate for introducing randomness in DSP processing
 /// LCG with Newlib/Musl characteristics: 64-bit seed, 31-bit output (see http://en.wikipedia.org/wiki/Linear_congruential_generator)
 /// Warning: This RNG is not cryptographically secure! Do not use it as such!
 class CAkRng
 {
 public:
     static constexpr AkUInt64 RANDOM_A = 6364136223846793005ULL;
     static constexpr AkUInt64 RANDOM_C = 1;
     static constexpr AkUInt32 RANDOM_MAX = 0x7FFFFFFF; // 31 bits
  
     /// Initialize using the specified seed
     CAkRng(AkUInt64 uSeed)
         : m_uSeed(uSeed)
     {}
  
     /// Returns the current seed value of the RNG
     inline AkUInt64 Seed() const
     {
         return m_uSeed;
     }
  
     /// Returns the next random number to be generated without advancing the RNG state
     inline AkUInt32 Peek() const
     {
         return Peek(m_uSeed);
     }
  
     /// Returns a random 31-bit unsigned integer
     inline AkUInt32 Random()
     {
         return Random(m_uSeed);
     }
  
     /// Returns a random 31-bit integer
     inline AkInt32 RandomInt()
     {
         return RandomInt(m_uSeed);
     }
  
     /// Returns a random float from 0.0 to 1.0
     AkReal32 RandomFloat()
     {
         return (AkReal32)Random(m_uSeed) / (AkReal32)RANDOM_MAX;
     }
  
     /// Returns a random 31-bit unsigned integer using provided seed
     static inline AkInt32 Random(AkUInt64 &io_uSeed)
     {
         io_uSeed = io_uSeed * RANDOM_A + RANDOM_C;
         return Peek(io_uSeed);
     }
  
     /// Returns a random 31-bit integer using provided seed
     static inline AkInt32 RandomInt(AkUInt64 &io_uSeed)
     {
         io_uSeed = io_uSeed * RANDOM_A + RANDOM_C;
         return (AkInt32)Peek(io_uSeed);
     }
  
     /// Returns the next random number to be generated without advancing the RNG state
     static inline AkUInt32 Peek(AkUInt64 in_uSeed)
     {
         return (AkUInt32)(in_uSeed >> 33);
     }
  
 private:
     AkUInt64 m_uSeed;
 };