From 83652270aa81b3bc67fbee1465360e2c22e0813c Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Thu, 17 May 2018 14:13:13 -0400
Subject: [PATCH] Generate MIDI with Gamepad driver, allow negative CC values
 in MIDI-CC

---
 include/gamepad.hpp              |  5 ++-
 src/Core/MIDICCToCVInterface.cpp |  5 +--
 src/gamepad.cpp                  | 60 +++++++++++++++++++++++++-------
 src/midi.cpp                     |  2 ++
 4 files changed, 57 insertions(+), 15 deletions(-)

diff --git a/include/gamepad.hpp b/include/gamepad.hpp
index 84cb5299..cd0f71ed 100644
--- a/include/gamepad.hpp
+++ b/include/gamepad.hpp
@@ -12,11 +12,14 @@ const int GAMEPAD_DRIVER = -10;
 
 struct GamepadInputDevice : MidiInputDevice {
 	int deviceId;
+	std::vector<uint8_t> ccs;
+	void step();
+	void updateCc(int index, uint8_t cc);
 };
 
 
 struct GamepadInputDriver : MidiInputDriver {
-	GamepadInputDevice gamepadInputDevices[16];
+	GamepadInputDevice devices[16];
 
 	GamepadInputDriver();
 	std::vector<int> getDeviceIds() override;
diff --git a/src/Core/MIDICCToCVInterface.cpp b/src/Core/MIDICCToCVInterface.cpp
index 20dba917..ba43d335 100644
--- a/src/Core/MIDICCToCVInterface.cpp
+++ b/src/Core/MIDICCToCVInterface.cpp
@@ -19,7 +19,7 @@ struct MIDICCToCVInterface : Module {
 	};
 
 	MidiInputQueue midiInput;
-	uint8_t cvs[16];
+	int8_t cvs[16];
 	ExponentialFilter ccFilters[16];
 
 	int learningId = -1;
@@ -64,7 +64,8 @@ struct MIDICCToCVInterface : Module {
 				// Set CV
 				for (int i = 0; i < 16; i++) {
 					if (learnedCcs[i] == cc) {
-						cvs[i] = msg.value();
+						// Allow CC to be negative if the 8th bit is set
+						cvs[i] = msg.data2;
 					}
 				}
 			} break;
diff --git a/src/gamepad.cpp b/src/gamepad.cpp
index a52c75a4..dfacc53e 100644
--- a/src/gamepad.cpp
+++ b/src/gamepad.cpp
@@ -6,9 +6,46 @@
 namespace rack {
 
 
+void GamepadInputDevice::step() {
+	if (!glfwJoystickPresent(deviceId))
+		return;
+	// Get gamepad state
+	int numAxes;
+	const float *axes = glfwGetJoystickAxes(deviceId, &numAxes);
+	int numButtons;
+	const unsigned char *buttons = glfwGetJoystickButtons(deviceId, &numButtons);
+	// Update state
+	ccs.resize(numAxes + numButtons);
+	for (int i = 0; i < numAxes; i++) {
+		// Allow CC value to go negative, but clamp at -127 instead of -128 for symmetry
+		updateCc(i, clamp((int) (axes[i] * 127), -127, 127));
+	}
+	for (int i = 0; i < numButtons; i++) {
+		updateCc(numAxes + i, buttons[i] ? 127 : 0);
+	}
+}
+
+void GamepadInputDevice::updateCc(int index, uint8_t cc) {
+	if ((int) ccs.size() < index)
+		return;
+
+	if (cc != ccs[index]) {
+		ccs[index] = cc;
+
+		// Send MIDI message
+		MidiMessage msg;
+		// MIDI channel 1
+		msg.cmd = (0xb << 4) | 0;
+		msg.data1 = index;
+		msg.data2 = ccs[index];
+		onMessage(msg);
+	}
+}
+
+
 GamepadInputDriver::GamepadInputDriver() {
 	for (int i = 0; i < 16; i++) {
-		gamepadInputDevices[i].deviceId = i;
+		devices[i].deviceId = i;
 	}
 }
 
@@ -37,31 +74,30 @@ MidiInputDevice *GamepadInputDriver::getDevice(int deviceId) {
 	if (!(0 <= deviceId && deviceId < 16))
 		return NULL;
 
-	return &gamepadInputDevices[deviceId];
+	return &devices[deviceId];
 }
 
 
-static GamepadInputDriver *gamepadInputDriver = NULL;
+static GamepadInputDriver *driver = NULL;
 
 
 void gamepadStep() {
+	// Check if the driver has been instantiated
+	if (!driver)
+		return;
+
 	for (int i = 0; i < 16; i++) {
 		if (glfwJoystickPresent(i)) {
-			const char *name = glfwGetJoystickName(i);
-			int numButtons;
-			const unsigned char *buttons = glfwGetJoystickButtons(i, &numButtons);
-			int numAxes;
-			const float *axes = glfwGetJoystickAxes(i, &numAxes);
-			debug("%d %s", i, name);
+			driver->devices[i].step();
 		}
 	}
 }
 
 MidiInputDriver *gamepadGetInputDriver() {
-	if (!gamepadInputDriver) {
-		gamepadInputDriver = new GamepadInputDriver();
+	if (!driver) {
+		driver = new GamepadInputDriver();
 	}
-	return gamepadInputDriver;
+	return driver;
 }
 
 
diff --git a/src/midi.cpp b/src/midi.cpp
index 0c479956..cf333b8b 100644
--- a/src/midi.cpp
+++ b/src/midi.cpp
@@ -50,6 +50,7 @@ std::vector<int> MidiIO::getDriverIds() {
 
 std::string MidiIO::getDriverName(int driverId) {
 	switch (driverId) {
+		case -1: return "None";
 		case RtMidi::UNSPECIFIED: return "Unspecified";
 		case RtMidi::MACOSX_CORE: return "Core MIDI";
 		case RtMidi::LINUX_ALSA: return "ALSA";
@@ -179,6 +180,7 @@ void MidiInputQueue::onMessage(MidiMessage message) {
 			return;
 	}
 
+	// Push to queue
 	if ((int) queue.size() < queueSize)
 		queue.push(message);
 }