FlameIsolate

The power of integral_isolates neatly packaged in flame_isolate for your Flame game.

If you’ve ever used the compute function before, you will feel right at home. This mixin allows you to run CPU-intensive code in an isolate.

To use it in your game you just need to add flame_isolate to your pubspec.yaml.

Usage

Just add the mixin FlameIsolate to your component and start utilizing the power of an isolate as simple as running the compute function.

Example:

class MyGame extends FlameGame with FlameIsolate {
  ...
  @override
  void update(double dt) {
    if (shouldRecalculate) {
      isolate(recalculateWorld, worldData).then(updateWorld);
    }
    ...
  }
  ...
}

Performance note

Keep in mind that every component with FlameIsolate mixin that you create and add to your game will create a new isolate. This means you will probably want to create a manager component to manage a lot of “dumber” components. Think of it like ants, where the queen controls the worker ants. If every individual worker ant got its own isolate, it would be a total waste of power, hence you would put it on the queen, which in turn tells all the worker ants what to do.

A simple example of this can be found in the example application for the FlameIsolate package.

Backpressure Strategies

Backpressure strategies are a way to cope with the job queue when job items are produced more rapidly than the isolate can handle them. This presents the problem of what to do with such a growing backlog of unhandled jobs. To mitigate this problem this library funnels all jobs through a job queue handler. Also known as BackpressureStrategy.

The ones currently supported are:

• NoBackPressureStrategy that basically does not handle back pressure. It uses a FIFO stack for storing a backlog of unhandled jobs. -ReplaceBackpressureStrategy that has a job queue with size one, and discards the queue upon adding a new job.

• DiscardNewBackPressureStrategy that has a job queue with size one, and as long as the queue is populated a new job will not be added.

You can specify a backpressure strategy by overriding the backpressureStrategy field. This will create the isolate with the specified strategy when the component is mounted.

class MyGame extends FlameGame with FlameIsolate {
  @override
  BackpressureStrategy get backpressureStrategy => ReplaceBackpressureStrategy();
  ...
}