ResourceGroup class Assets and loading

Tracks a set of in-flight resource loads so a scene can wait for all of them before it is shown, and report aggregate progress while they run.

Every loader in Flutter Scene returns a Future that completes only once the resource and its dependencies are decoded and resident on the GPU, so a completed future means "ready to render this frame". A ResourceGroup collects those futures, exposes a progress value for a loading bar, and completes ready once they have all settled. Pass one to a SceneView (via its loading argument) to hold the scene off-screen behind a loading widget until it is fully assembled, instead of drawing it half-built.

final loading = ResourceGroup();
final terrain = loading.add(loadScene('terrain.fscene'));
final env = loading.add(
  EnvironmentMap.fromEquirectImageAsset(assetPath: 'sky.hdr'),
);
loading.addAll([
  Node.fromGlbAsset('player.glb'),
  Texture2D.fromAsset('coin.png'),
]);

// Drive a progress bar from loading.progress, or just await:
await loading.ready;
scene.add(await terrain);

progress counts completed loads over the total tracked, so it can jump backward if you add more loads after it has advanced. Track every load up front (before reading progress) to avoid that.

Constructors

ResourceGroup()
Creates an empty group. A group with nothing tracked is immediately isReady, and its ready future is already complete.

Properties

completed → int
The number of tracked loads that have settled.
no setter
failures → List<Object>
The errors from any tracked loads that failed, in completion order.
no setter
hasFailures → bool
Whether any tracked load failed.
no setter
hashCode → int
The hash code for this object.
no setterinherited
isReady → bool
Whether every tracked load has settled.
no setter
progress → ValueListenable<double>
Fraction of tracked loads that have settled, in the range 0 to 1.
no setter
ready → Future<void>
Completes once every load tracked so far has settled (succeeded or failed). Never throws; inspect failures for any errors.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
total → int
The number of loads tracked so far.
no setter

Methods

add<T>(Future<T> load) → Future<T>
Tracks load and returns it unchanged, so the call reads inline:
addAll(Iterable<Future<Object?>> loads) → void
Tracks each of loads. Convenience for calling add in a loop when you do not need the individual futures back.
dispose() → void
Releases the progress notifier. Call when the group is no longer used; after disposal the group must not be added to or listened on.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited