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