Add MIDI "Loopback" driver.

adapters/standalone.cpp

@@ -7,6 +7,7 @@
 #include <rtmidi.hpp>
 #include <keyboard.hpp>
 #include <gamepad.hpp>
+#include <midiloopback.hpp>
 #include <settings.hpp>
 #include <engine/Engine.hpp>
 #include <app/common.hpp>
@@ -174,6 +175,7 @@ int main(int argc, char* argv[]) {
 	rtmidiInit();
 	keyboard::init();
 	gamepad::init();
+	midiloopback::init();
 	INFO("Initializing plugins");
 	plugin::init();
 	INFO("Initializing browser");
@@ -189,6 +191,8 @@ int main(int argc, char* argv[]) {
 
 	// Initialize context
 	contextSet(new Context);
+	INFO("Creating MIDI loopback");
+	APP->midiLoopbackContext = new midiloopback::Context;
 	INFO("Creating engine");
 	APP->engine = new engine::Engine;
 	INFO("Creating history state");

include/context.hpp

@@ -35,6 +35,11 @@ struct Scene;
 } // namespace app
 
 
+namespace midiloopback {
+struct Context;
+} // namespace midiloopback
+
+
 /** Rack instance state
 */
 struct Context {
@@ -44,6 +49,7 @@ struct Context {
 	window::Window* window = NULL;
 	history::State* history = NULL;
 	patch::Manager* patch = NULL;
+	midiloopback::Context* midiLoopbackContext = NULL;
 
 	~Context();
 };

include/midiloopback.hpp

@@ -0,0 +1,25 @@
+#pragma once
+#include <common.hpp>
+#include <midi.hpp>
+
+
+namespace rack {
+namespace midiloopback {
+
+
+struct Device;
+
+
+struct Context {
+	Device* devices[1] = {};
+
+	Context();
+	~Context();
+};
+
+
+PRIVATE void init();
+
+
+} // namespace midiloopback
+} // namespace rack

src/context.cpp

@@ -4,7 +4,7 @@
 #include <engine/Engine.hpp>
 #include <app/Scene.hpp>
 #include <history.hpp>
-#include <settings.hpp>
+#include <midiloopback.hpp>
 
 
 namespace rack {
@@ -38,6 +38,10 @@ Context::~Context() {
 	INFO("Deleting engine");
 	delete engine;
 	engine = NULL;
+
+	INFO("Deleting MIDI loopback");
+	delete midiLoopbackContext;
+	midiLoopbackContext = NULL;
 }
 
 

src/midiloopback.cpp

@@ -0,0 +1,103 @@
+#include <context.hpp>
+#include <midiloopback.hpp>
+
+
+namespace rack {
+namespace midiloopback {
+
+
+static const int DRIVER_ID = -12;
+
+
+struct Device : midi::InputDevice, midi::OutputDevice {
+	std::string getName() override {
+		return "Loopback";
+	}
+
+	void sendMessage(const midi::Message& message) override {
+		onMessage(message);
+	}
+};
+
+
+struct Driver : midi::Driver {
+	std::string getName() override {
+		return "Loopback";
+	}
+
+	// Input methods
+	std::vector<int> getInputDeviceIds() override {
+		return {0};
+	}
+	int getDefaultInputDeviceId() override {
+		return 0;
+	}
+	std::string getInputDeviceName(int deviceId) override {
+		return getDevice(deviceId)->getName();
+	}
+	midi::InputDevice* subscribeInput(int deviceId, midi::Input* input) override {
+		midi::InputDevice* inputDevice = getDevice(deviceId);
+		if (!inputDevice)
+			return NULL;
+		inputDevice->subscribe(input);
+		return inputDevice;
+	}
+	void unsubscribeInput(int deviceId, midi::Input* input) override {
+		midi::InputDevice* inputDevice = getDevice(deviceId);
+		if (!inputDevice)
+			return;
+		inputDevice->unsubscribe(input);
+	}
+
+	// Output methods
+	std::vector<int> getOutputDeviceIds() override {
+		return {0};
+	}
+	int getDefaultOutputDeviceId() override {
+		return 0;
+	}
+	std::string getOutputDeviceName(int deviceId) override {
+		return getDevice(deviceId)->getName();
+	}
+	midi::OutputDevice* subscribeOutput(int deviceId, midi::Output* output) override {
+		midi::OutputDevice* outputDevice = getDevice(deviceId);
+		if (!outputDevice)
+			return NULL;
+		outputDevice->subscribe(output);
+		return outputDevice;
+	}
+	void unsubscribeOutput(int deviceId, midi::Output* output) override {
+		midi::OutputDevice* outputDevice = getDevice(deviceId);
+		if (!outputDevice)
+			return;
+		outputDevice->unsubscribe(output);
+	}
+
+	// Custom methods
+	Device* getDevice(int deviceId) {
+		if (!APP->midiLoopbackContext)
+			return NULL;
+		if (deviceId != 0)
+			return NULL;
+		return APP->midiLoopbackContext->devices[deviceId];
+	}
+};
+
+
+Context::Context() {
+	devices[0] = new Device;
+}
+
+Context::~Context() {
+	delete devices[0];
+}
+
+
+void init() {
+	Driver* driver = new Driver;
+	midi::addDriver(DRIVER_ID, driver);
+}
+
+
+} // namespace midiloopback
+} // namespace rack