Prevent jitter in Parallax2D

scene/2d/parallax_2d.cpp

@@ -83,7 +83,11 @@ void Parallax2D::_validate_property(PropertyInfo &p_property) const {
 void Parallax2D::_camera_moved(const Transform2D &p_transform, const Point2 &p_screen_offset, const Point2 &p_adj_screen_pos) {
 	if (!ignore_camera_scroll) {
 		if (get_viewport() && get_viewport()->is_snap_2d_transforms_to_pixel_enabled()) {
-			set_screen_offset((p_adj_screen_pos + Vector2(0.5, 0.5)).floor());
+			Size2 vps = get_viewport_rect().size;
+			Vector2 offset;
+			offset.x = ((int)vps.width % 2) ? 0.0 : 0.5;
+			offset.y = ((int)vps.height % 2) ? 0.0 : 0.5;
+			set_screen_offset((p_adj_screen_pos + offset).floor());
 		} else {
 			set_screen_offset(p_adj_screen_pos);
 		}