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#ifndef __RANDOM_H__
#define __RANDOM_H__
#include <curand_kernel.h>
#include "physical_constants.h"
__device__ float uniform(curandState *s, const float &low, const float &high)
{
return low + curand_uniform(s)*(high-low);
}
__device__ float3 uniform_sphere(curandState *s)
{
float theta = uniform(s, 0.0f, 2*PI);
float u = uniform(s, -1.0f, 1.0f);
float c = sqrtf(1.0f-u*u);
return make_float3(c*cosf(theta), c*sinf(theta), u);
}
extern "C"
{
__global__ void init_rng(int nthreads, curandState *s, unsigned long long seed, unsigned long long offset)
{
int id = blockIdx.x*blockDim.x + threadIdx.x;
if (id >= nthreads)
return;
curand_init(seed, id, offset, &s[id]);
}
__global__ void fill_uniform(int nthreads, curandState *s, float *a, float low, float high)
{
int id = blockIdx.x*blockDim.x + threadIdx.x;
if (id >= nthreads)
return;
a[id] = uniform(&s[id], low, high);
}
__global__ void fill_uniform_sphere(int nthreads, curandState *s, float3 *a)
{
int id = blockIdx.x*blockDim.x + threadIdx.x;
if (id >= nthreads)
return;
a[id] = uniform_sphere(&s[id]);
}
} // extern "c"
#endif
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