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DependentExtensions/cat/rand/StdRand.hpp

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+/*
+	Copyright (c) 2009-2010 Christopher A. Taylor.  All rights reserved.
+
+	Redistribution and use in source and binary forms, with or without
+	modification, are permitted provided that the following conditions are met:
+
+	* Redistributions of source code must retain the above copyright notice,
+	  this list of conditions and the following disclaimer.
+	* Redistributions in binary form must reproduce the above copyright notice,
+	  this list of conditions and the following disclaimer in the documentation
+	  and/or other materials provided with the distribution.
+	* Neither the name of LibCat nor the names of its contributors may be used
+	  to endorse or promote products derived from this software without
+	  specific prior written permission.
+
+	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+	AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+	IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+	ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+	LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+	CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+	SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+	INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+	CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+	ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+	POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef CAT_STDRAND_HPP
+#define CAT_STDRAND_HPP
+
+#include <cat/Platform.hpp>
+
+namespace cat {
+
+
+// Microsoft VC++ 7.0 stdlib srand(), rand(), old RANDU()
+class StandardRand
+{
+protected:
+    s32 seed;
+
+public:
+    StandardRand(u32 ns = 0) { seed = ns; }
+
+    inline void srand32(u32 ns) { seed = ns; } // 32-bit version
+    inline void srand16(u16 ns) { seed = ns; } // 16-bit version (yup)
+
+    u16 rand();		// Linear Congruential Generator: X = X * M + A (mod N)
+    u16 randu();	// RANDU LCG: X = X * M (mod N)
+	float sfrand();	// Fast [-1.f,1.f] generator from Inigo Quilez (2005)
+};
+
+
+// Non-linear congruential 32-bit random mixing function for given x, y and seed
+// This function is used in every example of Perlin noise I found online for some reason!
+u32 NLCRand32(int x, int y, u32 seed);
+
+// Uses NLCRand32 as a front-end, and then maps the output to a number between -1 and 1
+float NLCRandNorm(int x, int y, u32 seed);
+
+
+
+} // namespace cat
+
+#endif // CAT_STDRAND_HPP