Qt: Add audio backend selection (only cubeb for now)

pcsx2-qt/Settings/AudioSettingsWidget.cpp

@@ -18,6 +18,8 @@
 #include <QtWidgets/QMessageBox>
 #include <algorithm>
 
+#include "pcsx2/SPU2/Global.h"
+
 #include "AudioSettingsWidget.h"
 #include "QtHost.h"
 #include "QtUtils.h"
@@ -69,7 +71,10 @@ AudioSettingsWidget::AudioSettingsWidget(SettingsDialog* dialog, QWidget* parent
 
 	SettingWidgetBinder::BindWidgetToEnumSetting(sif, m_ui.outputModule, "SPU2/Output", "OutputModule", s_output_module_entries, s_output_module_values, DEFAULT_OUTPUT_MODULE);
 	SettingWidgetBinder::BindWidgetToIntSetting(sif, m_ui.latency, "SPU2/Output", "Latency", DEFAULT_OUTPUT_LATENCY);
+	connect(m_ui.outputModule, &QComboBox::currentIndexChanged, this, &AudioSettingsWidget::outputModuleChanged);
+	connect(m_ui.backend, &QComboBox::currentIndexChanged, this, &AudioSettingsWidget::outputBackendChanged);
 	connect(m_ui.latency, &QSlider::valueChanged, this, &AudioSettingsWidget::updateLatencyLabel);
+	outputModuleChanged();
 
 	SettingWidgetBinder::BindWidgetToIntSetting(sif, m_ui.volume, "SPU2/Mixing", "FinalVolume", DEFAULT_VOLUME);
 	connect(m_ui.volume, &QSlider::valueChanged, this, &AudioSettingsWidget::updateVolumeLabel);
@@ -99,6 +104,59 @@ void AudioSettingsWidget::expansionModeChanged()
 	m_ui.dplLevel->setDisabled(!expansion51);
 }
 
+void AudioSettingsWidget::outputModuleChanged()
+{
+	const std::string module_name(m_dialog->getEffectiveStringValue("SPU2/Output", "OutputModule", DEFAULT_OUTPUT_MODULE));
+	const char* const* backend_names = GetOutputModuleBackends(module_name.c_str());
+
+	const std::string backend_name(m_dialog->getEffectiveStringValue("SPU2/Output", "BackendName", ""));
+
+	QSignalBlocker sb(m_ui.backend);
+	m_ui.backend->clear();
+
+	if (m_dialog->isPerGameSettings())
+	{
+		const QString global_backend(QString::fromStdString(Host::GetStringSettingValue("SPU2/Output", "BackendName", "")));
+		m_ui.backend->addItem(tr("Use Global Setting [%1]").arg(global_backend.isEmpty() ? tr("Default") : global_backend));
+	}
+
+	m_ui.backend->setEnabled(backend_names != nullptr);
+	m_ui.backend->addItem(tr("(Default)"));
+	if (!backend_names || backend_name.empty())
+		m_ui.backend->setCurrentIndex(0);
+
+	if (backend_names)
+	{
+		for (u32 i = 0; backend_names[i] != nullptr; i++)
+		{
+			const int index = m_ui.backend->count();
+			m_ui.backend->addItem(QString::fromUtf8(backend_names[i]));
+			if (backend_name == backend_names[i])
+				m_ui.backend->setCurrentIndex(index);
+		}
+	}
+}
+
+void AudioSettingsWidget::outputBackendChanged()
+{
+	int index = m_ui.backend->currentIndex();
+	if (m_dialog->isPerGameSettings())
+	{
+		if (index == 0)
+		{
+			m_dialog->setStringSettingValue("SPU2/Output", "BackendName", std::nullopt);
+			return;
+		}
+
+		index--;
+	}
+
+	if (index == 0)
+		m_dialog->setStringSettingValue("SPU2/Output", "BackendName", "");
+	else
+		m_dialog->setStringSettingValue("SPU2/Output", "BackendName", m_ui.backend->currentText().toUtf8().constData());
+}
+
 void AudioSettingsWidget::updateVolumeLabel()
 {
 	m_ui.volumeLabel->setText(tr("%1%").arg(m_ui.volume->value()));

pcsx2-qt/Settings/AudioSettingsWidget.h

@@ -31,6 +31,8 @@ public:
 
 private Q_SLOTS:
 	void expansionModeChanged();
+	void outputModuleChanged();
+	void outputBackendChanged();
 	void updateVolumeLabel();
 	void updateLatencyLabel();
 	void updateTimestretchSequenceLengthLabel();

pcsx2-qt/Settings/AudioSettingsWidget.ui

@@ -130,7 +130,7 @@
         </item>
        </widget>
       </item>
-	  <item row="3" column="0">
+      <item row="3" column="0">
        <widget class="QLabel" name="label_3b">
         <property name="text">
          <string>ProLogic Level:</string>
@@ -173,16 +173,16 @@
        </widget>
       </item>
       <item row="0" column="1">
-       <widget class="QComboBox" name="outputModule" />
+       <widget class="QComboBox" name="outputModule"/>
       </item>
-      <item row="1" column="0">
+      <item row="2" column="0">
        <widget class="QLabel" name="label_5">
         <property name="text">
          <string>Latency:</string>
         </property>
        </widget>
       </item>
-      <item row="1" column="1">
+      <item row="2" column="1">
        <layout class="QHBoxLayout" name="horizontalLayout">
         <item>
          <widget class="QSlider" name="latency">
@@ -215,6 +215,16 @@
         </item>
        </layout>
       </item>
+      <item row="1" column="0">
+       <widget class="QLabel" name="label_9">
+        <property name="text">
+         <string>Output Backend:</string>
+        </property>
+       </widget>
+      </item>
+      <item row="1" column="1">
+       <widget class="QComboBox" name="backend"/>
+      </item>
      </layout>
     </widget>
    </item>

pcsx2/SPU2/SndOut.cpp

@@ -64,6 +64,11 @@ public:
 	{
 		return "No Sound (Emulate SPU2 only)";
 	}
+
+	const char* const* GetBackendNames() const override
+	{
+		return nullptr;
+	}
 };
 
 static NullOutModule s_NullOut;
@@ -93,6 +98,19 @@ int FindOutputModuleById(const char* omodid)
 	return modcnt;
 }
 
+const char* const* GetOutputModuleBackends(const char* omodid)
+{
+	for (SndOutModule* mod : mods)
+	{
+		if (mod && std::strcmp(mod->GetIdent(), omodid) == 0)
+		{
+			return mod->GetBackendNames();
+		}
+	}
+
+	return nullptr;
+}
+
 StereoOut32* SndBuffer::m_buffer;
 s32 SndBuffer::m_size;
 alignas(4) volatile s32 SndBuffer::m_rpos;

pcsx2/SPU2/SndOut.h

@@ -34,6 +34,10 @@ extern int SampleRate;
 
 extern int FindOutputModuleById(const char* omodid);
 
+// Returns a null-terminated list of backends for the specified module.
+// nullptr is returned if the specified module does not have multiple backends.
+extern const char* const* GetOutputModuleBackends(const char* omodid);
+
 // Implemented in Config.cpp
 extern float VolumeAdjustFL;
 extern float VolumeAdjustC;
@@ -641,6 +645,9 @@ public:
 	// (for use in configuration screen)
 	virtual const char* GetLongName() const = 0;
 
+	// Returns a null-terminated list of backends, or nullptr.
+	virtual const char* const* GetBackendNames() const = 0;
+
 	virtual bool Init() = 0;
 	virtual void Close() = 0;
 

pcsx2/SPU2/SndOut_Cubeb.cpp

@@ -363,6 +363,11 @@ public:
 		return "Cubeb (Cross-platform)";
 	}
 
+	const char* const* GetBackendNames() const override
+	{
+		return cubeb_get_backend_names();
+	}
+
 	void ReadSettings()
 	{
 #ifndef PCSX2_CORE
@@ -371,12 +376,12 @@ public:
 
 		// TODO: Once the config stuff gets merged, drop the wxString here.
 		wxString backend;
-		CfgReadStr(L"Cubeb", L"BackendName", backend, L"");
+		CfgReadStr(L"SPU2/Output", L"BackendName", backend, L"");
 		m_Backend = StringUtil::wxStringToUTF8String(backend);
 #else
 		m_SuggestedLatencyMinimal = Host::GetBoolSettingValue("Cubeb", "MinimalSuggestedLatency", false);
 		m_SuggestedLatencyMS = std::clamp(Host::GetIntSettingValue("Cubeb", "ManualSuggestedLatencyMS", MINIMUM_LATENCY_MS), MINIMUM_LATENCY_MS, MAXIMUM_LATENCY_MS);
-		m_Backend = Host::GetStringSettingValue("Cubeb", "BackendName", "");
+		m_Backend = Host::GetStringSettingValue("SPU2/Output", "BackendName", "");
 #endif
 	}
 };

pcsx2/SPU2/Windows/SndOut_XAudio2.cpp

@@ -380,6 +380,11 @@ public:
 		return "XAudio 2 (Recommended)";
 	}
 
+	const char* const* GetBackendNames() const override
+	{
+		return nullptr;
+	}
+
 } static XA2;
 
 SndOutModule* XAudio2Out = &XA2;