From a099a77e821724afcd36840f457727ba21e27a45 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?kleines=20Filmr=C3=B6llchen?= <malu.bertsch@gmail.com>
Date: Sat, 20 Nov 2021 17:44:12 +0100
Subject: [PATCH] SoundPlayer+LibDSP: Move the FFT implementation to LibDSP

LibDSP can greatly benefit from this nice FFT implementation, so let's
move it into the fitting library :^)

Note that this now requires linking SoundPlayer against LibDSP. That's
not an issue (LibDSP is rather small currently anyways), as we can
probably make great use of it in the future anyways.
---
 .../Applications/SoundPlayer/BarsVisualizationWidget.cpp    | 4 ++--
 Userland/Applications/SoundPlayer/CMakeLists.txt            | 3 +--
 Userland/Libraries/LibDSP/CMakeLists.txt                    | 1 +
 .../AudioAlgorithms.cpp => Libraries/LibDSP/FFT.cpp}        | 6 +++++-
 .../AudioAlgorithms.h => Libraries/LibDSP/FFT.h}            | 6 +++++-
 5 files changed, 14 insertions(+), 6 deletions(-)
 rename Userland/{Applications/SoundPlayer/AudioAlgorithms.cpp => Libraries/LibDSP/FFT.cpp} (97%)
 rename Userland/{Applications/SoundPlayer/AudioAlgorithms.h => Libraries/LibDSP/FFT.h} (66%)

diff --git a/Userland/Applications/SoundPlayer/BarsVisualizationWidget.cpp b/Userland/Applications/SoundPlayer/BarsVisualizationWidget.cpp
index 4c0a584768..adf2dbdb73 100644
--- a/Userland/Applications/SoundPlayer/BarsVisualizationWidget.cpp
+++ b/Userland/Applications/SoundPlayer/BarsVisualizationWidget.cpp
@@ -5,8 +5,8 @@
  */
 
 #include "BarsVisualizationWidget.h"
-#include "AudioAlgorithms.h"
 #include <AK/Math.h>
+#include <LibDSP/FFT.h>
 #include <LibGUI/Event.h>
 #include <LibGUI/Menu.h>
 #include <LibGUI/Painter.h>
@@ -25,7 +25,7 @@ void BarsVisualizationWidget::paint_event(GUI::PaintEvent& event)
     if (m_sample_buffer.is_empty())
         return;
 
-    fft(m_sample_buffer, false);
+    LibDSP::fft(m_sample_buffer, false);
     double max = AK::sqrt(m_sample_count * 2.);
 
     double freq_bin = m_samplerate / (double)m_sample_count;
diff --git a/Userland/Applications/SoundPlayer/CMakeLists.txt b/Userland/Applications/SoundPlayer/CMakeLists.txt
index 578078938e..26f5e31c1f 100644
--- a/Userland/Applications/SoundPlayer/CMakeLists.txt
+++ b/Userland/Applications/SoundPlayer/CMakeLists.txt
@@ -13,11 +13,10 @@ set(SOURCES
     SampleWidget.cpp
     SoundPlayerWidgetAdvancedView.cpp
     BarsVisualizationWidget.cpp
-    AudioAlgorithms.cpp
     NoVisualizationWidget.cpp
     M3UParser.cpp
     PlaylistWidget.cpp
 )
 
 serenity_app(SoundPlayer ICON app-sound-player)
-target_link_libraries(SoundPlayer LibAudio LibGUI)
+target_link_libraries(SoundPlayer LibAudio LibDSP LibGUI)
diff --git a/Userland/Libraries/LibDSP/CMakeLists.txt b/Userland/Libraries/LibDSP/CMakeLists.txt
index a5de6f120e..f7dc72fcd1 100644
--- a/Userland/Libraries/LibDSP/CMakeLists.txt
+++ b/Userland/Libraries/LibDSP/CMakeLists.txt
@@ -3,6 +3,7 @@ set(SOURCES
     Track.cpp
     Effects.cpp
     Synthesizers.cpp
+    FFT.cpp
 )
 
 serenity_lib(LibDSP dsp)
diff --git a/Userland/Applications/SoundPlayer/AudioAlgorithms.cpp b/Userland/Libraries/LibDSP/FFT.cpp
similarity index 97%
rename from Userland/Applications/SoundPlayer/AudioAlgorithms.cpp
rename to Userland/Libraries/LibDSP/FFT.cpp
index b25de59797..8083333f96 100644
--- a/Userland/Applications/SoundPlayer/AudioAlgorithms.cpp
+++ b/Userland/Libraries/LibDSP/FFT.cpp
@@ -4,10 +4,12 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include "AudioAlgorithms.h"
+#include "FFT.h"
 #include <AK/Complex.h>
 #include <AK/Math.h>
 
+namespace LibDSP {
+
 // This function uses the input vector as output too. therefore, if you wish to
 // leave it intact, pass a copy to this function
 //
@@ -56,3 +58,5 @@ void fft(Vector<Complex<double>>& sample_data, bool invert)
             data[i] /= n;
     }
 }
+
+}
diff --git a/Userland/Applications/SoundPlayer/AudioAlgorithms.h b/Userland/Libraries/LibDSP/FFT.h
similarity index 66%
rename from Userland/Applications/SoundPlayer/AudioAlgorithms.h
rename to Userland/Libraries/LibDSP/FFT.h
index 904c9acefe..d13d358af2 100644
--- a/Userland/Applications/SoundPlayer/AudioAlgorithms.h
+++ b/Userland/Libraries/LibDSP/FFT.h
@@ -9,4 +9,8 @@
 #include <AK/Complex.h>
 #include <AK/Vector.h>
 
-void fft(Vector<Complex<double>>& sample_data, bool invert);
+namespace LibDSP {
+
+void fft(Vector<Complex<double>>& sample_data, bool invert = false);
+
+}