port from perforce

evoke-64k/ev10/random.h

@@ -0,0 +1,112 @@
+#pragma once
+
+struct RandomGenerator
+{
+	float getRand()
+	{
+		return 2.0f * ( genFloat() - 0.5f );
+	}
+
+	float getRand( float a, float b )
+	{
+		return genFloat( a, b );
+	}
+
+	int getRandInt( int a, int b )
+	{
+		return genInteger( a, b );		
+	}
+
+		enum RandConstants 
+	{                     
+		KK = 17, 
+		JJ = 10, 
+		R1 = 13, 
+		R2 =  9 
+	};
+
+	int g_iP1;
+	int g_iP2;
+
+	unsigned g_u32Buffer[ KK ];
+
+	float genFloat()
+	{
+		unsigned int u32Tmp;
+		// nächste Zahl
+		u32Tmp= _lrotl( g_u32Buffer[ g_iP2 ], R1 ) + 
+			_lrotl( g_u32Buffer[ g_iP1 ], R2 );
+		g_u32Buffer[ g_iP1 ]= u32Tmp;
+
+		// Listen rotieren
+		g_iP1--;
+		if ( g_iP1 < 0 ) 
+		{ 
+			g_iP1 = KK - 1;
+		}
+
+		g_iP2--;
+		if ( g_iP2 < 0 ) 
+		{
+			g_iP2 = KK - 1;
+		}
+
+		// conversion to float:
+		union 
+		{
+			double f; 
+			unsigned long i[2];
+		} convert;
+
+		convert.i[0] =  u32Tmp << 20;
+		convert.i[1] = ( u32Tmp >> 12 ) | 0x3FF00000;
+		return (float)( convert.f - 1.0f );
+
+	}
+	
+	unsigned int getLastTempValue()
+	{
+		return g_u32Buffer[ g_iP1 ];
+	}
+
+	void setSeed( unsigned int Seed )
+	{
+		int i;
+
+		// Buffer füllen
+		for( i= 0; i < KK; i++ )
+		{
+			Seed= Seed * 2891336453 + 1;
+			g_u32Buffer[ i ] = Seed;
+		}
+
+		// Pointer initialisieren
+		g_iP1= 0;
+		g_iP2= JJ;
+
+		// Anfang der Folge wegwerfen
+		for( i= 0; i < 9; i++ )
+		{
+			genFloat();
+		}
+	}
+
+	int genInteger(	int iMin, int iMax )
+	{
+		float fInterval = (float)( iMax - iMin ) + 0.96875f;
+		float fRet= fInterval * genFloat();
+		fRet+= (float)iMin;
+		int iRet= (int)( fRet - 0.484375f );
+		//int iRet= (int)( fRet );
+		assert( iRet >= iMin );
+		assert( iRet <= iMax );
+		return iRet;
+	}
+
+	float genFloat( float fMin, float fMax )
+	{
+		float fInterval = (float)( fMax - fMin );
+
+		return fMin + fInterval * genFloat();
+	}
+};