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/*
* Copyright (c) 2008-2017, 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.
*/
#ifndef APEX_RAND_H
#define APEX_RAND_H
#include "PxMath.h"
#include "PxVec3.h"
#include "ApexUsingNamespace.h"
namespace nvidia
{
namespace apex
{
// "Quick and Dirty Symmetric Random number generator" - returns a uniform deviate in [-1.0,1.0)
class QDSRand
{
uint32_t mSeed;
public:
PX_CUDA_CALLABLE PX_INLINE QDSRand(uint32_t seed = 0) : mSeed(seed) {}
PX_CUDA_CALLABLE PX_INLINE void setSeed(uint32_t seed = 0)
{
mSeed = seed;
}
PX_CUDA_CALLABLE PX_INLINE uint32_t seed() const
{
return mSeed;
}
PX_CUDA_CALLABLE PX_INLINE uint32_t nextSeed()
{
mSeed = mSeed * 1664525L + 1013904223L;
return mSeed;
}
PX_CUDA_CALLABLE PX_INLINE float getNext()
{
union U32F32
{
uint32_t u;
float f;
} r;
r.u = 0x40000000 | (nextSeed() >> 9);
return r.f - 3.0f;
}
PX_CUDA_CALLABLE PX_INLINE float getScaled(const float min, const float max)
{
const float scale = (max - min) / 2.0f;
return ((getNext() + 1.0f) * scale) + min;
}
PX_CUDA_CALLABLE PX_INLINE PxVec3 getScaled(const PxVec3& min, const PxVec3& max)
{
return PxVec3(getScaled(min.x, max.x), getScaled(min.y, max.y), getScaled(min.z, max.z));
}
PX_CUDA_CALLABLE PX_INLINE float getUnit()
{
union U32F32
{
uint32_t u;
float f;
} r;
r.u = 0x3F800000 | (nextSeed() >> 9);
return r.f - 1.0f;
}
};
// "Quick and Dirty Normal Random number generator" - returns normally-distributed values
class QDNormRand
{
QDSRand mBase;
public:
PX_CUDA_CALLABLE PX_INLINE QDNormRand(uint32_t seed = 0) : mBase(seed) {}
PX_CUDA_CALLABLE PX_INLINE void setSeed(uint32_t seed = 0)
{
mBase.setSeed(seed);
}
PX_CUDA_CALLABLE PX_INLINE uint32_t setSeed() const
{
return mBase.seed();
}
PX_CUDA_CALLABLE PX_INLINE uint32_t nextSeed()
{
return mBase.nextSeed();
}
PX_CUDA_CALLABLE PX_INLINE float getNext()
{
//Using Box-Muller transform (see http://en.wikipedia.org/wiki/Box_Muller_transform)
float u, v, s;
do
{
u = mBase.getNext();
v = mBase.getNext();
s = u * u + v * v;
}
while (s >= 1.0);
return u * PxSqrt(-2.0f * PxLog(s) / s);
}
PX_CUDA_CALLABLE PX_INLINE float getScaled(const float m, const float s)
{
return m + s * getNext();
}
};
}
} // end namespace nvidia::apex
#endif
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