Piano: Add export action

This is a pretty rudimentary WAV export function for Piano.

3 files changed, 49 insertions, 0 deletions

diff --git a/Applications/Piano/AudioEngine.cpp b/Applications/Piano/AudioEngine.cpp
index 8eec8938d8..c3ada8eb28 100644
--- a/Applications/Piano/AudioEngine.cpp
+++ b/Applications/Piano/AudioEngine.cpp
@@ -125,6 +125,24 @@ void AudioEngine::fill_buffer(FixedArray<Sample>& buffer)
     swap(m_front_buffer_ptr, m_back_buffer_ptr);
 }
 
+void AudioEngine::reset()
+{
+    memset(m_front_buffer.data(), 0, buffer_size);
+    memset(m_back_buffer.data(), 0, buffer_size);
+    m_front_buffer_ptr = &m_front_buffer;
+    m_back_buffer_ptr = &m_back_buffer;
+
+    m_delay_buffers.clear();
+
+    memset(m_note_on, 0, sizeof(m_note_on));
+    memset(m_power, 0, sizeof(m_power));
+    memset(m_envelope, 0, sizeof(m_envelope));
+
+    m_time = 0;
+    m_current_column = 0;
+    m_previous_column = horizontal_notes - 1;
+}
+
 // All of the information for these waves is on Wikipedia.
 
 double AudioEngine::sine(size_t note)
diff --git a/Applications/Piano/AudioEngine.h b/Applications/Piano/AudioEngine.h
index e722e0cfd0..72d3e17a13 100644
--- a/Applications/Piano/AudioEngine.h
+++ b/Applications/Piano/AudioEngine.h
@@ -40,6 +40,7 @@ public:
     ~AudioEngine();
 
     const FixedArray<Sample>& buffer() const { return *m_front_buffer_ptr; }
+    void reset();
     Switch roll_note(int y, int x) const { return m_roll_notes[y][x]; }
     int current_column() const { return m_current_column; }
     int octave() const { return m_octave; }
diff --git a/Applications/Piano/main.cpp b/Applications/Piano/main.cpp
index 4be57b21c2..18b0e3d02e 100644
--- a/Applications/Piano/main.cpp
+++ b/Applications/Piano/main.cpp
@@ -28,11 +28,14 @@
 #include "AudioEngine.h"
 #include "MainWidget.h"
 #include <LibAudio/ClientConnection.h>
+#include <LibAudio/WavWriter.h>
 #include <LibCore/File.h>
 #include <LibGUI/GAboutDialog.h>
 #include <LibGUI/GAction.h>
 #include <LibGUI/GApplication.h>
+#include <LibGUI/GFilePicker.h>
 #include <LibGUI/GMenuBar.h>
+#include <LibGUI/GMessageBox.h>
 #include <LibGUI/GWindow.h>
 #include <LibThread/Thread.h>
 
@@ -53,6 +56,10 @@ int main(int argc, char** argv)
     window->set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/app-piano.png"));
     window->show();
 
+    Audio::WavWriter wav_writer;
+    Optional<String> save_path;
+    bool need_to_write_wav = false;
+
     LibThread::Thread audio_thread([&] {
         auto audio = Core::File::construct("/dev/audio");
         if (!audio->open(Core::IODevice::WriteOnly)) {
@@ -66,6 +73,17 @@ int main(int argc, char** argv)
             audio->write(reinterpret_cast<u8*>(buffer.data()), buffer_size);
             Core::EventLoop::current().post_event(*main_widget, make<Core::CustomEvent>(0));
             Core::EventLoop::wake();
+
+            if (need_to_write_wav) {
+                need_to_write_wav = false;
+                audio_engine.reset();
+                while (audio_engine.current_column() < horizontal_notes - 1) {
+                    audio_engine.fill_buffer(buffer);
+                    wav_writer.write_samples(reinterpret_cast<u8*>(buffer.data()), buffer_size);
+                }
+                audio_engine.reset();
+                wav_writer.finalize();
+            }
         }
     });
     audio_thread.start();
@@ -77,6 +95,18 @@ int main(int argc, char** argv)
         GUI::Application::the().quit(0);
         return;
     }));
+    app_menu->add_action(GUI::Action::create("Export", { Mod_Ctrl, Key_E }, [&](const GUI::Action&) {
+        save_path = GUI::FilePicker::get_save_filepath("Untitled", "wav");
+        if (!save_path.has_value())
+            return;
+        wav_writer.set_file(save_path.value());
+        if (wav_writer.has_error()) {
+            GUI::MessageBox::show(String::format("Failed to export WAV file: %s", wav_writer.error_string()), "Error", GUI::MessageBox::Type::Error);
+            wav_writer.clear_error();
+            return;
+        }
+        need_to_write_wav = true;
+    }));
     menubar->add_menu(move(app_menu));
 
     auto help_menu = GUI::Menu::construct("Help");