Engine directory for ticket #1

Engine/source/math/mRandom.h

@@ -0,0 +1,140 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2012 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#ifndef _MRANDOM_H_
+#define _MRANDOM_H_
+
+#ifndef _PLATFORMASSERT_H_
+#include "platform/platformAssert.h"
+#endif
+
+
+//--------------------------------------
+/// Base class for random number generators
+class MRandomGenerator
+{
+protected:
+   MRandomGenerator() {}
+   S32  mSeed;
+
+public:
+   virtual ~MRandomGenerator() {}
+   
+   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()) * (1.0f/2147483647.0f);
+}
+
+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);
+   virtual ~MRandomLCG() {}
+
+   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);
+   virtual ~MRandomR250() {}
+
+   void setSeed(S32 s);
+// using MRandomGenerator::randI;
+   U32 randI();
+};
+
+
+typedef MRandomLCG MRandom;
+
+extern MRandomLCG gRandGen;
+
+
+#endif //_MRANDOM_H_