54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/*
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Copyright (c) 2009 David Bucciarelli (davibu@interfree.it)
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be included
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in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef _SIMPLERND_H
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#define _SIMPLERND_H
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/*
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* A Simple Random number generator
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* from http://en.wikipedia.org/wiki/Random_number_generator
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*/
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#ifndef SMALLPT_GPU
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static float GetRandom(unsigned int *seed0, unsigned int *seed1) {
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*seed0 = 36969 * ((*seed0) & 65535) + ((*seed0) >> 16);
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*seed1 = 18000 * ((*seed1) & 65535) + ((*seed1) >> 16);
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unsigned int ires = ((*seed0) << 16) + (*seed1);
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/* Convert to float */
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union {
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float f;
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unsigned int ui;
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} res;
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res.ui = (ires & 0x007fffff) | 0x40000000;
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return (res.f - 2.f) / 2.f;
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}
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#endif
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#endif /* _SIMPLERND_H */
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