Prevent double input events on gamepad when running through steam input #79706

Co-authored-by: Eoin O'Neill <eoinoneill1991@gmail.com>

core/input/input.cpp

@@ -72,6 +72,7 @@ void Input::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_joy_axis", "device", "axis"), &Input::get_joy_axis);
 	ClassDB::bind_method(D_METHOD("get_joy_name", "device"), &Input::get_joy_name);
 	ClassDB::bind_method(D_METHOD("get_joy_guid", "device"), &Input::get_joy_guid);
+	ClassDB::bind_method(D_METHOD("should_ignore_device", "vendor_id", "product_id"), &Input::should_ignore_device);
 	ClassDB::bind_method(D_METHOD("get_connected_joypads"), &Input::get_connected_joypads);
 	ClassDB::bind_method(D_METHOD("get_joy_vibration_strength", "device"), &Input::get_joy_vibration_strength);
 	ClassDB::bind_method(D_METHOD("get_joy_vibration_duration", "device"), &Input::get_joy_vibration_duration);

core/input/input.h

@@ -99,6 +99,7 @@ public:
 	virtual void remove_joy_mapping(String p_guid) = 0;
 	virtual bool is_joy_known(int p_device) = 0;
 	virtual String get_joy_guid(int p_device) const = 0;
+	virtual bool should_ignore_device(int p_vendor_id, int p_product_id) const = 0;
 	virtual Vector2 get_joy_vibration_strength(int p_device) = 0;
 	virtual float get_joy_vibration_duration(int p_device) = 0;
 	virtual uint64_t get_joy_vibration_timestamp(int p_device) = 0;

doc/classes/Input.xml

@@ -360,6 +360,15 @@
 				[b]Note:[/b] This value can be immediately overwritten by the hardware sensor value on Android and iOS.
 			</description>
 		</method>
+		<method name="should_ignore_device" qualifiers="const">
+			<return type="bool" />
+			<argument index="0" name="vendor_id" type="int" />
+			<argument index="1" name="product_id" type="int" />
+			<description>
+				Queries whether an input device should be ignored or not. Devices can be ignored by setting the environment variable [code]SDL_GAMECONTROLLER_IGNORE_DEVICES[/code]. Read the [url=https://wiki.libsdl.org/SDL2]SDL documentation[/url] for more information.
+				[b]Note:[/b] Some 3rd party tools can contribute to the list of ignored devices. For example, [i]SteamInput[/i] creates virtual devices from physical devices for remapping purposes. To avoid handling the same input device twice, the original device is added to the ignore list.
+			</description>
+		</method>
 		<method name="start_joy_vibration">
 			<return type="void" />
 			<argument index="0" name="device" type="int" />

main/input_default.cpp

@@ -840,6 +840,27 @@ InputDefault::InputDefault() {
 			parse_mapping(entries[i]);
 		}
 	}
+
+	String env_ignore_devices = OS::get_singleton()->get_environment("SDL_GAMECONTROLLER_IGNORE_DEVICES");
+	if (!env_ignore_devices.empty()) {
+		Vector<String> entries = env_ignore_devices.split(",");
+		for (int i = 0; i < entries.size(); i++) {
+			Vector<String> vid_pid = entries[i].split("/");
+
+			if (vid_pid.size() < 2) {
+				continue;
+			}
+
+			print_verbose(vformat("Device Ignored -- Vendor: %s Product: %s", vid_pid[0], vid_pid[1]));
+			const uint16_t vid_unswapped = vid_pid[0].hex_to_int();
+			const uint16_t pid_unswapped = vid_pid[1].hex_to_int();
+			const uint16_t vid = BSWAP16(vid_unswapped);
+			const uint16_t pid = BSWAP16(pid_unswapped);
+
+			uint32_t full_id = (((uint32_t)vid) << 16) | ((uint16_t)pid);
+			ignored_device_ids.insert(full_id);
+		}
+	}
 }
 
 void InputDefault::joy_button(int p_device, int p_button, bool p_pressed) {
@@ -1334,6 +1355,11 @@ String InputDefault::get_joy_guid(int p_device) const {
 	return OS::get_singleton()->get_joy_guid(p_device);
 }
 
+bool InputDefault::should_ignore_device(int p_vendor_id, int p_product_id) const {
+	uint32_t full_id = (((uint32_t)p_vendor_id) << 16) | ((uint16_t)p_product_id);
+	return ignored_device_ids.has(full_id);
+}
+
 //platforms that use the remapping system can override and call to these ones
 bool InputDefault::is_joy_mapped(int p_device) {
 	if (joy_names.has(p_device)) {

main/input_default.h

@@ -203,6 +203,8 @@ private:
 
 	Vector<JoyDeviceMapping> map_db;
 
+	Set<uint32_t> ignored_device_ids;
+
 	JoyEvent _get_mapped_button_event(const JoyDeviceMapping &mapping, int p_button);
 	JoyEvent _get_mapped_axis_event(const JoyDeviceMapping &mapping, int p_axis, float p_value);
 	void _get_mapped_hat_events(const JoyDeviceMapping &mapping, int p_hat, JoyEvent r_events[HAT_MAX]);
@@ -300,6 +302,8 @@ public:
 	virtual bool is_joy_known(int p_device);
 	virtual String get_joy_guid(int p_device) const;
 
+	bool should_ignore_device(int p_vendor_id, int p_product_id) const;
+
 	virtual String get_joy_button_string(int p_button);
 	virtual String get_joy_axis_string(int p_axis);
 	virtual int get_joy_axis_index_from_string(String p_axis);

platform/x11/joypad_linux.cpp

@@ -387,6 +387,16 @@ void JoypadLinux::open_joypad(const char *p_path) {
 			return;
 		}
 
+		uint16_t vendor = BSWAP16(inpid.vendor);
+		uint16_t product = BSWAP16(inpid.product);
+		uint16_t version = BSWAP16(inpid.version);
+
+		if (input->should_ignore_device(vendor, product)) {
+			// This can be true in cases where Steam is passing information into the game to ignore
+			// original gamepads when using virtual rebindings (See SteamInput).
+			return;
+		}
+
 		MutexLock lock(joypads_mutex[joy_num]);
 		Joypad &joypad = joypads[joy_num];
 		joypad.reset();
@@ -395,10 +405,6 @@ void JoypadLinux::open_joypad(const char *p_path) {
 		setup_joypad_properties(joypad);
 		sprintf(uid, "%04x%04x", BSWAP16(inpid.bustype), 0);
 		if (inpid.vendor && inpid.product && inpid.version) {
-			uint16_t vendor = BSWAP16(inpid.vendor);
-			uint16_t product = BSWAP16(inpid.product);
-			uint16_t version = BSWAP16(inpid.version);
-
 			sprintf(uid + String(uid).length(), "%04x%04x%04x%04x%04x%04x", vendor, 0, product, 0, version, 0);
 			input->joy_connection_changed(joy_num, true, name, uid);
 		} else {