random.h

 
/*
 * Copyright (c) 2008 - 2009 NVIDIA Corporation.  All rights reserved.
 *
 * NVIDIA Corporation and its licensors retain all intellectual property and proprietary
 * rights in and to this software, related documentation and any modifications thereto.
 * Any use, reproduction, disclosure or distribution of this software and related
 * documentation without an express license agreement from NVIDIA Corporation is strictly
 * prohibited.
 *
 * TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, THIS SOFTWARE IS PROVIDED *AS IS*
 * AND NVIDIA AND ITS SUPPLIERS DISCLAIM ALL WARRANTIES, EITHER EXPRESS OR IMPLIED,
 * INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  IN NO EVENT SHALL NVIDIA OR ITS SUPPLIERS BE LIABLE FOR ANY
 * SPECIAL, INCIDENTAL, INDIRECT, OR CONSEQUENTIAL DAMAGES WHATSOEVER (INCLUDING, WITHOUT
 * LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF
 * BUSINESS INFORMATION, OR ANY OTHER PECUNIARY LOSS) ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF NVIDIA HAS BEEN ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGES
 */
 
// #include <optixu/optixu_math_namespace.h>
 
template<unsigned int N>
static __host__ __device__ __inline__ unsigned int tea(unsigned int val0, unsigned int val1) {
    unsigned int v0 = val0;
    unsigned int v1 = val1;
    unsigned int s0 = 0;
 
    for (unsigned int n = 0; n < N; n++) {
        s0 += 0x9e3779b9;
        v0 += ((v1 << 4) + 0xa341316c) ^ (v1 + s0) ^ ((v1 >> 5) + 0xc8013ea4);
        v1 += ((v0 << 4) + 0xad90777d) ^ (v0 + s0) ^ ((v0 >> 5) + 0x7e95761e);
    }
 
    return v0;
}
 
// Generate random unsigned int in [0, 2^24)
static __host__ __device__ __inline__ unsigned int lcg(unsigned int &prev) {
    const unsigned int LCG_A = 1664525u;
    const unsigned int LCG_C = 1013904223u;
    prev = (LCG_A * prev + LCG_C);
    return prev & 0x00FFFFFF;
}
 
// Generate random float in [0, 1)
static __host__ __device__ __inline__ float rnd(unsigned int &prev) {
    return ((float) lcg(prev) / (float) 0x01000000);
}