Add Chromium-only Blender WebEngine parity work

blender-5.2.0/source/blender/blenlib/BLI_fftw.hh

@@ -0,0 +1,30 @@
+/* SPDX-FileCopyrightText: 2024 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bli
+ */
+
+#include "BLI_math_vector_types.hh"
+
+#pragma once
+
+namespace blender::fftw {
+
+/**
+ * FFTW's real to complex and complex to real transforms are more efficient when their input has a
+ * specific size. This function finds the most optimal size that is more than or equal the given
+ * size. The input data can then be zero padded to the optimal size for better performance. See
+ * Section 4.3.3 Real-data DFTs in the FFTW manual for more information.
+ */
+int optimal_size_for_real_transform(int size);
+int2 optimal_size_for_real_transform(int2 size);
+
+/**
+ * Initialize the float variant of FFTW. This essentially setup the multi-threading hooks to enable
+ * multi-threading using TBB's parallel_for and makes the FFTW planner thread safe.
+ */
+void initialize_float();
+
+}  // namespace blender::fftw