-Allows more fine grained notifications (hence better performance) than using the global scene tree signals (node added and removed).
-Required for #55950
(cherry picked from commit fbd9599b04)
Most frames there will be no change in project settings, and it makes no sense to read settings every frame in case of changes, as a large number of string compares are involved.
This PR adds a signal to ProjectSettings that can be subscribed to in order to keep local settings up to date with ProjectSettings.
In addition a function `ProjectSettings::has_changes()` is provided for objects outside the signal system (e.g. Rasterizers).
A regression had occurred whereby particle systems in DYNAMIC mode weren't added to the room correctly.
This PR recognise the case and bypasses the function to retrieve geometry, as retrieving the geometry is not necessary for DYNAMIC objects as they should not affect the room bound. Their AABB will be retrieved during gameplay rather than once off at level conversion.
When editor continuous redraws is switched off, the editor only redraws when a redraw_request was issued by an element in the scene. This works well in most situations, but when scenes have dynamic content they will continuously issue redraw_requests.
This can be fine on high power desktops but can be an annoyance on lower power machines.
This PR splits redraw requests into high and low priority requests, defaulting to high priority. Requests due to e.g. shaders using TIME are assigned low priority.
An extra editor setting is used to record the user preference and an extra option is added to the editor spinner menu, to allow the user to select between 3 modes:
* Continuous
* Update all changes
* Update vital changes
A common source of errors is to call functions (such as round()) expecting them to work in place, but them actually being designed only to return the processed value. Not using the return value in this case in indicative of a bug, and can be flagged as a warning by using the [[nodiscard]] attribute.
