wavelength.h

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/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
 * SPDX-FileCopyrightText: 2011-2022 Blender Foundation
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Adapted code from Open Shading Language. */
 
#pragma once
 
#include "kernel/svm/math_util.h"
 
CCL_NAMESPACE_BEGIN
 
/* Wavelength to RGB */
 
ccl_device_noinline void svm_node_wavelength(KernelGlobals kg,
                                             ccl_private ShaderData *sd,
                                             ccl_private float *stack,
                                             uint wavelength,
                                             uint color_out)
{
  const float lambda_nm = stack_load_float(stack, wavelength);
 
  float3 color = svm_math_wavelength_color_xyz(lambda_nm);
  color = xyz_to_rgb(kg, color);
  color *= 1.0f / 2.52f;  // Empirical scale from lg to make all comps <= 1
 
  /* Clamp to zero if values are smaller */
  color = max(color, make_float3(0.0f, 0.0f, 0.0f));
 
  stack_store_float3(stack, color_out, color);
}
 
CCL_NAMESPACE_END