42 lines
902 B
C
42 lines
902 B
C
/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
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* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted code from Open Shading Language. */
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#pragma once
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#include "util/defines.h"
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CCL_NAMESPACE_BEGIN
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/* Multiple importance sampling utilities. */
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ccl_device float balance_heuristic(const float a, const float b)
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{
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return (a) / (a + b);
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}
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ccl_device float balance_heuristic_3(const float a, const float b, float c)
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{
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return (a) / (a + b + c);
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}
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ccl_device float power_heuristic(const float a, const float b)
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{
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return (a * a) / (a * a + b * b);
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}
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ccl_device float power_heuristic_3(const float a, const float b, float c)
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{
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return (a * a) / (a * a + b * b + c * c);
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}
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ccl_device float max_heuristic(const float a, const float b)
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{
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return (a > b) ? 1.0f : 0.0f;
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}
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CCL_NAMESPACE_END
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