Rack/src/gamepad.cpp

#include "gamepad.hpp"
#include "util/common.hpp"
#include <GLFW/glfw3.h>


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);

	// Convert axes to MIDI CC
	ccs.resize(numAxes);
	for (int i = 0; i < numAxes; i++) {
		// Allow CC value to go negative, but clamp at -127 instead of -128 for symmetry
		int8_t cc = clamp((int) (axes[i] * 127), -127, 127);
		if (cc != ccs[i]) {
			ccs[i] = cc;

			// Send MIDI message
			MidiMessage msg;
			// MIDI channel 1
			msg.cmd = (0xb << 4) | 0;
			msg.data1 = i;
			msg.data2 = ccs[i];
			onMessage(msg);
		}
	}

	// Convert buttons to MIDI notes
	notes.resize(numButtons);
	for (int i = 0; i < numButtons; i++) {
		bool note = !!buttons[i];
		if (note != notes[i]) {
			notes[i] = note;

			MidiMessage msg;
			msg.cmd = ((note ? 0x9 : 0x8) << 4);
			msg.data1 = i;
			msg.data2 = 127;
			onMessage(msg);
		}
	}
}


GamepadInputDriver::GamepadInputDriver() {
	for (int i = 0; i < 16; i++) {
		devices[i].deviceId = i;
	}
}

std::vector<int> GamepadInputDriver::getDeviceIds() {
	std::vector<int> deviceIds;
	for (int i = 0; i < 16; i++) {
		if (glfwJoystickPresent(i)) {
			deviceIds.push_back(i);
		}
	}
	return deviceIds;
}

std::string GamepadInputDriver::getDeviceName(int deviceId) {
	if (!(0 <= deviceId && deviceId < 16))
		return "";

	const char *name = glfwGetJoystickName(deviceId);
	if (name) {
		return name;
	}
	return stringf("Gamepad %d (unavailable)", deviceId + 1);
}

MidiInputDevice *GamepadInputDriver::getDevice(int deviceId) {
	if (!(0 <= deviceId && deviceId < 16))
		return NULL;

	return &devices[deviceId];
}


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)) {
			driver->devices[i].step();
		}
	}
}

MidiInputDriver *gamepadGetInputDriver() {
	if (!driver) {
		driver = new GamepadInputDriver();
	}
	return driver;
}


} // namespace rack