Initial commit

Torque/SDK/engine/math/mRandom.h

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+//-----------------------------------------------------------------------------
+// Torque Game Engine
+// Copyright (C) GarageGames.com, Inc.
+//-----------------------------------------------------------------------------
+
+#ifndef _MRANDOM_H_
+#define _MRANDOM_H_
+
+
+#ifndef _PLATFORM_H_
+#include "platform/platform.h"
+#endif
+
+
+//--------------------------------------
+/// Base class for random number generators
+class MRandomGenerator
+{
+protected:
+   MRandomGenerator() {}
+   S32  mSeed;
+
+public:
+   void setSeed();
+   S32  getSeed() { return mSeed; }
+   virtual void setSeed(S32 s) = 0;
+
+   virtual U32 randI( void ) = 0;      ///< 0..2^31 random number generator
+   virtual F32  randF( void );         ///< 0.0 .. 1.0 F32 random number generator
+   S32 randI(S32 i, S32 n);            ///< i..n integer random number generator
+   F32 randF(F32 i, F32 n);            ///< i..n F32 random number generator
+};
+
+
+//--------------------------------------
+inline F32 MRandomGenerator::randF()
+{
+   // default: multiply by 1/(2^31)
+   return  F32(randI()) * F32(1.0/2147483647.0);
+}
+
+inline S32 MRandomGenerator::randI(S32 i, S32 n)
+{
+   AssertFatal(i<=n, "MRandomGenerator::randi: inverted range.");
+   return (S32)(i + (randI() % (n - i + 1)) );
+}
+
+inline F32 MRandomGenerator::randF(F32 i, F32 n)
+{
+   AssertFatal(i<=n, "MRandomGenerator::randf: inverted range.");
+   return (i + (n - i) * randF());
+}
+
+
+//--------------------------------------
+/// Linear Congruential Method, the "minimal standard generator"
+///
+/// Fast, farly good random numbers (better than using rand)
+///
+/// @author Park & Miller, 1988, Comm of the ACM, 31(10), pp. 1192-1201
+class MRandomLCG : public MRandomGenerator
+{
+protected:
+   static const S32 msQuotient;
+   static const S32 msRemainder;
+
+public:
+   MRandomLCG();
+   MRandomLCG(S32 s);
+
+   static void setGlobalRandSeed(U32 seed);
+
+   void setSeed(S32 s);
+//   using MRandomGenerator::randI;
+    S32 randI(S32 i, S32 n);            ///< i..n integer generator
+
+   U32 randI( void );
+
+};
+
+// Solution to "using" problem.
+inline S32 MRandomLCG::randI(S32 i, S32 n)
+{
+    return( MRandomGenerator::randI(i,n) );
+}
+
+
+//--------------------------------------
+/// Fast, very good random numbers
+///
+/// Period = 2^249
+///
+/// Kirkpatrick, S., and E. Stoll, 1981; A Very Fast Shift-Register
+///       Sequence Random Number Generator, Journal of Computational Physics,
+/// V. 40.
+///
+/// Maier, W.L., 1991; A Fast Pseudo Random Number Generator,
+/// Dr. Dobb's Journal, May, pp. 152 - 157
+class MRandomR250: public MRandomGenerator
+{
+private:
+   U32 mBuffer[250];
+   S32 mIndex;
+
+public:
+   MRandomR250();
+   MRandomR250(S32 s);
+
+   void setSeed(S32 s);
+// using MRandomGenerator::randI;
+   U32 randI();
+};
+
+
+typedef MRandomLCG MRandom;
+
+extern MRandomLCG gRandGen;
+
+
+#endif //_MRANDOM_H_