Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/kernel/svm/wavelength.h

@@ -0,0 +1,36 @@
+/* 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"
+#include "kernel/svm/node_types.h"
+#include "kernel/svm/util.h"
+
+#include "kernel/util/colorspace.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* Wavelength to RGB */
+
+ccl_device_noinline void svm_node_wavelength(KernelGlobals kg,
+                                             ccl_private float *ccl_restrict stack,
+                                             const ccl_global SVMNodeWavelength &ccl_restrict node)
+{
+  const float lambda_nm = stack_load(stack, node.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, node.color_offset, color);
+}
+
+CCL_NAMESPACE_END