Brecht Van Lommel
9cfc7967dd
* Replace license text in headers with SPDX identifiers. * Remove specific license info from outdated readme.txt, instead leave details to the source files. * Add list of SPDX license identifiers used, and corresponding license texts. * Update copyright dates while we're at it. Ref D14069, T95597
42 lines
1.0 KiB
C++
42 lines
1.0 KiB
C++
/* SPDX-License-Identifier: Apache-2.0
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* Copyright 2011-2022 Blender Foundation */
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#pragma once
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CCL_NAMESPACE_BEGIN
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/* Linear Congruential Generator */
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/* This is templated to handle multiple address spaces on Metal. */
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template<class T> ccl_device uint lcg_step_uint(T rng)
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{
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/* implicit mod 2^32 */
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*rng = (1103515245 * (*rng) + 12345);
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return *rng;
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}
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/* This is templated to handle multiple address spaces on Metal. */
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template<class T> ccl_device float lcg_step_float(T rng)
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{
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/* implicit mod 2^32 */
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*rng = (1103515245 * (*rng) + 12345);
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return (float)*rng * (1.0f / (float)0xFFFFFFFF);
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}
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ccl_device uint lcg_init(uint seed)
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{
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uint rng = seed;
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lcg_step_uint(&rng);
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return rng;
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}
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ccl_device_inline uint lcg_state_init(const uint rng_hash,
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const uint rng_offset,
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const uint sample,
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const uint scramble)
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{
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return lcg_init(rng_hash + rng_offset + sample * scramble);
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}
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CCL_NAMESPACE_END
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