Add an editor setting to invert 3D pan/orbit on the X axis

This also makes the invert Y axis option apply to 3D panning.

This closes #28082.

(cherry picked from commit 2c9d4ef9610cbfd43488e97d3c02624d9236d59d)

editor/editor_settings.cpp

@@ -526,6 +526,7 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	// 3D: Navigation
 	_initial_set("editors/3d/navigation/navigation_scheme", 0);
 	_initial_set("editors/3d/navigation/invert_y_axis", false);
+	_initial_set("editors/3d/navigation/invert_x_axis", false);
 	hints["editors/3d/navigation/navigation_scheme"] = PropertyInfo(Variant::INT, "editors/3d/navigation/navigation_scheme", PROPERTY_HINT_ENUM, "Godot,Maya,Modo");
 	_initial_set("editors/3d/navigation/zoom_style", 0);
 	hints["editors/3d/navigation/zoom_style"] = PropertyInfo(Variant::INT, "editors/3d/navigation/zoom_style", PROPERTY_HINT_ENUM, "Vertical, Horizontal");

editor/plugins/spatial_editor_plugin.cpp

@@ -2073,7 +2073,12 @@ void SpatialEditorViewport::_nav_pan(Ref<InputEventWithModifiers> p_event, const
 	camera_transform.translate(cursor.pos);
 	camera_transform.basis.rotate(Vector3(1, 0, 0), -cursor.x_rot);
 	camera_transform.basis.rotate(Vector3(0, 1, 0), -cursor.y_rot);
-	Vector3 translation(-p_relative.x * pan_speed, p_relative.y * pan_speed, 0);
+	const bool invert_x_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_x_axis");
+	const bool invert_y_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_y_axis");
+	Vector3 translation(
+			(invert_x_axis ? -1 : 1) * -p_relative.x * pan_speed,
+			(invert_y_axis ? -1 : 1) * p_relative.y * pan_speed,
+			0);
 	translation *= cursor.distance / DISTANCE_DEFAULT;
 	camera_transform.translate(translation);
 	cursor.pos = camera_transform.origin;
@@ -2113,17 +2118,24 @@ void SpatialEditorViewport::_nav_orbit(Ref<InputEventWithModifiers> p_event, con
 		_menu_option(VIEW_PERSPECTIVE);
 	}
 
-	real_t degrees_per_pixel = EditorSettings::get_singleton()->get("editors/3d/navigation_feel/orbit_sensitivity");
-	real_t radians_per_pixel = Math::deg2rad(degrees_per_pixel);
-	bool invert_y_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_y_axis");
+	const real_t degrees_per_pixel = EditorSettings::get_singleton()->get("editors/3d/navigation_feel/orbit_sensitivity");
+	const real_t radians_per_pixel = Math::deg2rad(degrees_per_pixel);
+	const bool invert_y_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_y_axis");
+	const bool invert_x_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_x_axis");
 
 	if (invert_y_axis) {
 		cursor.x_rot -= p_relative.y * radians_per_pixel;
 	} else {
 		cursor.x_rot += p_relative.y * radians_per_pixel;
 	}
-	cursor.y_rot += p_relative.x * radians_per_pixel;
+	// Clamp the Y rotation to roughly -90..90 degrees so the user can't look upside-down and end up disoriented.
 	cursor.x_rot = CLAMP(cursor.x_rot, -1.57, 1.57);
+
+	if (invert_x_axis) {
+		cursor.y_rot -= p_relative.x * radians_per_pixel;
+	} else {
+		cursor.y_rot += p_relative.x * radians_per_pixel;
+	}
 	name = "";
 	_update_name();
 }
@@ -2139,21 +2151,23 @@ void SpatialEditorViewport::_nav_look(Ref<InputEventWithModifiers> p_event, cons
 		_menu_option(VIEW_PERSPECTIVE);
 	}
 
-	real_t degrees_per_pixel = EditorSettings::get_singleton()->get("editors/3d/navigation_feel/orbit_sensitivity");
-	real_t radians_per_pixel = Math::deg2rad(degrees_per_pixel);
-	bool invert_y_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_y_axis");
+	const real_t degrees_per_pixel = EditorSettings::get_singleton()->get("editors/3d/navigation_feel/orbit_sensitivity");
+	const real_t radians_per_pixel = Math::deg2rad(degrees_per_pixel);
+	const bool invert_y_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_y_axis");
 
 	// Note: do NOT assume the camera has the "current" transform, because it is interpolated and may have "lag".
-	Transform prev_camera_transform = to_camera_transform(cursor);
+	const Transform prev_camera_transform = to_camera_transform(cursor);
 
 	if (invert_y_axis) {
 		cursor.x_rot -= p_relative.y * radians_per_pixel;
 	} else {
 		cursor.x_rot += p_relative.y * radians_per_pixel;
 	}
-	cursor.y_rot += p_relative.x * radians_per_pixel;
+	// Clamp the Y rotation to roughly -90..90 degrees so the user can't look upside-down and end up disoriented.
 	cursor.x_rot = CLAMP(cursor.x_rot, -1.57, 1.57);
 
+	cursor.y_rot += p_relative.x * radians_per_pixel;
+
 	// Look is like the opposite of Orbit: the focus point rotates around the camera
 	Transform camera_transform = to_camera_transform(cursor);
 	Vector3 pos = camera_transform.xform(Vector3(0, 0, 0));