Implement a virtual device rack

Author: juzzlin

CHANGELOG

@@ -7,6 +7,8 @@ New features:
 
 * Fix GitHub Issue #45: Implement a simple built-in sampler
 
+* Implements a virtual device rack
+
 Bug fixes:
 
 Other:

src/CMakeLists.txt

@@ -34,6 +34,8 @@ set(HEADER_FILES
   application/service/audio_worker.hpp
   application/service/automation_service.hpp
   application/service/copy_manager.hpp
+  application/service/device_rack.hpp
+  application/service/device_rack_controller.hpp
   application/service/device_service.hpp
   application/service/editor_service.hpp
   application/service/jack_service.hpp
@@ -151,6 +153,8 @@ set(SOURCE_FILES
   application/service/audio_worker.cpp
   application/service/automation_service.cpp
   application/service/copy_manager.cpp
+  application/service/device_rack.cpp
+  application/service/device_rack_controller.cpp
   application/service/device_service.cpp
   application/service/editor_service.cpp
   application/service/jack_service.cpp
@@ -260,6 +264,7 @@ set(QML_SOURCE_FILES
     ${QML_BASE_DIR}/Dialogs/AddMidiCcAutomationDialog.qml
     ${QML_BASE_DIR}/Dialogs/AddMidiCcSettingDialog.qml
     ${QML_BASE_DIR}/Dialogs/AddPitchBendAutomationDialog.qml
+    ${QML_BASE_DIR}/Dialogs/DeviceRackDialog.qml
     ${QML_BASE_DIR}/Dialogs/ColumnSettingsDialog.qml
     ${QML_BASE_DIR}/Dialogs/ColumnSettingsDialog_InstrumentSettings.qml
     ${QML_BASE_DIR}/Dialogs/ColumnSettingsDialog_MidiEffects.qml

src/application/application.cpp

@@ -47,6 +47,8 @@
 #include "service/property_service.hpp"
 #include "service/recent_files_manager.hpp"
 #include "service/sampler_controller.hpp"
+#include "service/device_rack.hpp"
+#include "service/device_rack_controller.hpp"
 #include "service/selection_service.hpp"
 #include "service/settings_service.hpp"
 #include "service/side_chain_service.hpp"
@@ -90,7 +92,9 @@ Application::Application(int & argc, char ** argv)
   , m_editorService { std::make_shared<EditorService>(m_selectionService, m_settingsService, m_automationService) }
   , m_audioEngine { std::make_shared<AudioEngine>() }
   , m_deviceService { std::make_shared<DeviceService>(m_audioEngine) }
-  , m_samplerController { std::make_shared<SamplerController>(std::make_shared<SamplerDevice>()) }
+  , m_deviceRack { std::make_unique<DeviceRack>(m_deviceService) }
+  , m_samplerController { std::make_shared<SamplerController>(nullptr) }
+  , m_deviceRackController { std::make_shared<DeviceRackController>(m_deviceService, m_samplerController) }
   , m_jackService { std::make_shared<JackService>(m_settingsService, m_audioEngine) }
   , m_audioService { std::make_shared<AudioService>(m_settingsService, m_jackService, m_audioEngine) }
   , m_eventSelectionModel { std::make_shared<EventSelectionModel>() }
@@ -115,7 +119,10 @@ Application::Application(int & argc, char ** argv)
   , m_noteColumnModelHandler { std::make_unique<NoteColumnModelHandler>(m_editorService, m_selectionService, m_automationService, m_settingsService) }
   , m_engine { std::make_unique<QQmlApplicationEngine>() }
 {
-    m_deviceService->registerDevice(m_samplerController->sampler());
+    m_deviceRack->initialize();
+    if (const auto sampler = std::dynamic_pointer_cast<SamplerDevice>(m_deviceService->device("Sampler 1"))) {
+        m_samplerController->setSampler(sampler);
+    }
     m_editorService->setMixerService(m_mixerService);
 
     registerTypes();
@@ -147,6 +154,7 @@ void Application::registerTypes()
     qmlRegisterType<AudioSettingsModel>("Noteahead", majorVersion, minorVersion, "AudioSettingsModel");
     qmlRegisterType<AutomationService>("Noteahead", majorVersion, minorVersion, "AutomationService");
     qmlRegisterType<ColumnSettingsModel>("Noteahead", majorVersion, minorVersion, "ColumnSettingsModel");
+    qmlRegisterType<DeviceRackController>("Noteahead", majorVersion, minorVersion, "DeviceRackController");
     qmlRegisterType<EditorService>("Noteahead", majorVersion, minorVersion, "EditorService");
     qmlRegisterType<EventSelectionModel>("Noteahead", majorVersion, minorVersion, "EventSelectionModel");
     qmlRegisterType<KeyboardService>("Noteahead", majorVersion, minorVersion, "KeyboardService");
@@ -181,6 +189,7 @@ void Application::setContextProperties()
     m_engine->rootContext()->setContextProperty("audioSettingsModel", m_audioSettingsModel.get());
     m_engine->rootContext()->setContextProperty("automationService", m_automationService.get());
     m_engine->rootContext()->setContextProperty("columnSettingsModel", m_columnSettingsModel.get());
+    m_engine->rootContext()->setContextProperty("deviceRackController", m_deviceRackController.get());
     m_engine->rootContext()->setContextProperty("deviceService", m_deviceService.get());
     m_engine->rootContext()->setContextProperty("samplerController", m_samplerController.get());
     m_engine->rootContext()->setContextProperty("editorService", m_editorService.get());
@@ -320,6 +329,10 @@ void Application::connectServices()
 
 void Application::connectDeviceService()
 {
+    connect(m_deviceRackController.get(), &DeviceRackController::samplerDialogRequested, m_applicationService.get(), [this]() {
+        emit m_applicationService->samplerDialogRequested();
+    });
+
     connect(m_editorService.get(), &EditorService::devicesSerializationRequested, m_deviceService.get(), &DeviceService::serializeToXml);
     connect(m_editorService.get(), &EditorService::devicesDeserializationRequested, m_deviceService.get(), &DeviceService::deserializeFromXml);
     connect(m_editorService.get(), &EditorService::projectPathChanged, m_deviceService.get(), &DeviceService::setProjectPath);

src/application/application.hpp

@@ -41,6 +41,8 @@ class AudioService;
 class AudioSettingsModel;
 class AutomationService;
 class ColumnSettingsModel;
+class DeviceRack;
+class DeviceRackController;
 class DeviceService;
 class EditorService;
 class EventSelectionModel;
@@ -142,7 +144,9 @@ class Application : public QObject
 
     std::shared_ptr<AudioEngine> m_audioEngine;
     std::shared_ptr<DeviceService> m_deviceService;
+    std::unique_ptr<DeviceRack> m_deviceRack;
     std::shared_ptr<SamplerController> m_samplerController;
+    std::shared_ptr<DeviceRackController> m_deviceRackController;
 
     std::shared_ptr<JackService> m_jackService;
 

src/application/models/sampler/sampler_pad_model.cpp

@@ -4,7 +4,7 @@
 
 namespace noteahead {
 
-SamplerPadModel::SamplerPadModel(std::shared_ptr<SamplerDevice> sampler, QObject * parent)
+SamplerPadModel::SamplerPadModel(SamplerDevice::SamplerDeviceS sampler, QObject * parent)
   : QAbstractListModel { parent }
   , m_sampler { std::move(sampler) }
 {
@@ -15,6 +15,25 @@ SamplerPadModel::SamplerPadModel(std::shared_ptr<SamplerDevice> sampler, QObject
     }
 }
 
+void SamplerPadModel::setSampler(SamplerDevice::SamplerDeviceS sampler)
+{
+    if (m_sampler == sampler) {
+        return;
+    }
+
+    beginResetModel();
+    if (m_sampler) {
+        m_sampler->disconnect(this);
+    }
+    m_sampler = std::move(sampler);
+    if (m_sampler) {
+        connect(m_sampler.get(), &SamplerDevice::dataChanged, this, [this]() {
+            emit dataChanged(index(0), index(PadCount - 1), { NoteName, FilePath, IsLoaded });
+        });
+    }
+    endResetModel();
+}
+
 int SamplerPadModel::rowCount(const QModelIndex & parent) const
 {
     if (parent.isValid()) {

src/application/models/sampler/sampler_pad_model.hpp

@@ -5,9 +5,9 @@
 #include <memory>
 #include <vector>
 
-namespace noteahead {
+#include "../../../domain/devices/sampler_device.hpp"
 
-class SamplerDevice;
+namespace noteahead {
 
 class SamplerPadModel : public QAbstractListModel
 {
@@ -22,7 +22,9 @@ class SamplerPadModel : public QAbstractListModel
     };
     Q_ENUM(Roles)
 
-    explicit SamplerPadModel(std::shared_ptr<SamplerDevice> sampler, QObject * parent = nullptr);
+    explicit SamplerPadModel(SamplerDevice::SamplerDeviceS sampler, QObject * parent = nullptr);
+
+    void setSampler(SamplerDevice::SamplerDeviceS sampler);
 
     int rowCount(const QModelIndex & parent = QModelIndex()) const override;
     QVariant data(const QModelIndex & index, int role = Qt::DisplayRole) const override;
@@ -31,7 +33,7 @@ class SamplerPadModel : public QAbstractListModel
     void updatePad(int padIndex);
 
 private:
-    std::shared_ptr<SamplerDevice> m_sampler;
+    SamplerDevice::SamplerDeviceS m_sampler;
     static constexpr int PadCount = 16;
     static constexpr int StartNote = 36;
 };

src/application/service/application_service.cpp

@@ -118,6 +118,12 @@ void ApplicationService::requestRecentFilesDialog()
     emit recentFilesDialogRequested();
 }
 
+void ApplicationService::requestDeviceRackDialog()
+{
+    juzzlin::L(TAG).info() << "Device Rack requested";
+    emit deviceRackDialogRequested();
+}
+
 void ApplicationService::requestOpenProject()
 {
     juzzlin::L(TAG).info() << "'Open file' requested";

src/application/service/application_service.hpp

@@ -89,6 +89,7 @@ class ApplicationService : public QObject
     Q_INVOKABLE void requestQuit();
 
     Q_INVOKABLE void requestRecentFilesDialog();
+    Q_INVOKABLE void requestDeviceRackDialog();
     Q_INVOKABLE void requestSaveProject();
     Q_INVOKABLE void requestSaveProjectAs();
     Q_INVOKABLE void requestSaveProjectAsTemplate();
@@ -148,6 +149,8 @@ class ApplicationService : public QObject
     void quitRequested();
 
     void recentFilesDialogRequested();
+    void deviceRackDialogRequested();
+    void samplerDialogRequested();
 
     void saveAsDialogRequested();
     void saveAsTemplateDialogRequested();

src/application/service/device_rack.cpp

@@ -0,0 +1,38 @@
+// This file is part of Noteahead.
+// Copyright (C) 2026 Jussi Lind <jussi.lind@iki.fi>
+//
+// Noteahead is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// Noteahead is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Noteahead. If not, see <http://www.gnu.org/licenses/>.
+
+#include "device_rack.hpp"
+#include "device_service.hpp"
+#include "../../domain/devices/sampler_device.hpp"
+
+namespace noteahead {
+
+DeviceRack::DeviceRack(DeviceServiceS deviceService)
+  : m_deviceService { std::move(deviceService) }
+{
+}
+
+DeviceRack::~DeviceRack() = default;
+
+void DeviceRack::initialize()
+{
+    for (size_t i = 1; i <= 4; i++) {
+        const auto sampler = std::make_shared<SamplerDevice>("Sampler " + std::to_string(i));
+        sampler->setId(i);
+        m_deviceService->registerDevice(sampler);
+    }
+}
+
+} // namespace noteahead

src/application/service/device_rack.hpp

@@ -0,0 +1,41 @@
+// This file is part of Noteahead.
+// Copyright (C) 2026 Jussi Lind <jussi.lind@iki.fi>
+//
+// Noteahead is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// Noteahead is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Noteahead. If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef DEVICE_RACK_HPP
+#define DEVICE_RACK_HPP
+
+#include <memory>
+#include <vector>
+
+namespace noteahead {
+
+class DeviceService;
+
+class DeviceRack
+{
+public:
+    using DeviceServiceS = std::shared_ptr<DeviceService>;
+    explicit DeviceRack(DeviceServiceS deviceService);
+    ~DeviceRack();
+
+    void initialize();
+
+private:
+    DeviceServiceS m_deviceService;
+};
+
+} // namespace noteahead
+
+#endif // DEVICE_RACK_HPP