Restrict relative mouse mode to Wayland users

irr/include/IrrlichtDevice.h

@@ -198,6 +198,9 @@ class IrrlichtDevice : public virtual IReferenceCounted
 	or similar. */
 	virtual bool supportsTouchEvents() const { return false; }
 
+	//! Checks whether windowing uses the Wayland protocol.
+	virtual bool isUsingWayland() const { return false; }
+
 	//! Get the current color format of the window
 	/** \return Color format of the window. */
 	virtual video::ECOLOR_FORMAT getColorFormat() const = 0;

irr/src/CIrrDeviceSDL.cpp

@@ -1248,6 +1248,15 @@ bool CIrrDeviceSDL::supportsTouchEvents() const
 	return true;
 }
 
+//! Checks whether windowing uses the Wayland protocol.
+bool CIrrDeviceSDL::isUsingWayland() const
+{
+	if (!Window)
+		return false;
+	auto *name = SDL_GetCurrentVideoDriver();
+	return name && !strcmp(name, "wayland");
+}
+
 //! returns if window is active. if not, nothing need to be drawn
 bool CIrrDeviceSDL::isWindowActive() const
 {

irr/src/CIrrDeviceSDL.h

@@ -96,6 +96,9 @@ class CIrrDeviceSDL : public CIrrDeviceStub
 	//! Checks if the Irrlicht device supports touch events.
 	bool supportsTouchEvents() const override;
 
+	//! Checks whether windowing uses the Wayland protocol.
+	bool isUsingWayland() const override;
+
 	//! Get the position of this window on screen
 	core::position2di getWindowPosition() override;
 

src/client/game.cpp

@@ -754,6 +754,7 @@ class Game {
 	f32  m_repeat_dig_time;
 	f32  m_cache_cam_smoothing;
 
+	bool m_enable_relative_mode = false;
 	bool m_invert_mouse;
 	bool m_enable_hotbar_mouse_wheel;
 	bool m_invert_hotbar_mouse_wheel;
@@ -896,6 +897,11 @@ bool Game::startup(bool *kill,
 
 	m_first_loop_after_window_activation = true;
 
+	// In principle we could always enable relative mouse mode, but it causes weird
+	// bugs on some setups (e.g. #14932), so we enable it only when it's required.
+	// That is: on Wayland, because it does not support mouse repositioning
+	m_enable_relative_mode = device->isUsingWayland();
+
 	m_touch_use_crosshair = g_settings->getBool("touch_use_crosshair");
 
 	g_client_translations->clear();
@@ -2349,8 +2355,10 @@ void Game::updateCameraDirection(CameraOrientation *cam, float dtime)
 	Since Minetest has its own code to synthesize mouse events from touch events,
 	this results in duplicated input. To avoid that, we don't enable relative
 	mouse mode if we're in touchscreen mode. */
-	if (cur_control)
-		cur_control->setRelativeMode(!g_touchcontrols && !isMenuActive());
+	if (cur_control) {
+		cur_control->setRelativeMode(m_enable_relative_mode &&
+			!g_touchcontrols && !isMenuActive());
+	}
 
 	if ((device->isWindowActive() && device->isWindowFocused()
 			&& !isMenuActive()) || input->isRandom()) {