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