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/* SPDX-License-Identifier: Apache-2.0
* Copyright 2011-2022 Blender Foundation */
#pragma once
CCL_NAMESPACE_BEGIN
/* Linear Congruential Generator */
/* This is templated to handle multiple address spaces on Metal. */
template<class T> ccl_device uint lcg_step_uint(T rng)
{
/* implicit mod 2^32 */
*rng = (1103515245 * (*rng) + 12345);
return *rng;
}
/* This is templated to handle multiple address spaces on Metal. */
template<class T> ccl_device float lcg_step_float(T rng)
{
/* implicit mod 2^32 */
*rng = (1103515245 * (*rng) + 12345);
return (float)*rng * (1.0f / (float)0xFFFFFFFF);
}
ccl_device uint lcg_init(uint seed)
{
uint rng = seed;
lcg_step_uint(&rng);
return rng;
}
ccl_device_inline uint lcg_state_init(const uint rng_hash,
const uint rng_offset,
const uint sample,
const uint scramble)
{
return lcg_init(rng_hash + rng_offset + sample * scramble);
}
CCL_NAMESPACE_END
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