feat: add applyLifespanToChildren to Particle generate (#1911)

packages/flame/lib/src/particles/particle.dart

@@ -28,9 +28,11 @@ abstract class Particle {
  int count = 10,
  required ParticleGenerator generator,
  double? lifespan,
+ bool applyLifespanToChildren = true,
  }) {
  return ComposedParticle(
  lifespan: lifespan,
+ applyLifespanToChildren: applyLifespanToChildren,
  children: List<Particle>.generate(count, generator),
  );
  }

packages/flame/test/particles/composed_particle_test.dart

@@ -86,5 +86,45 @@ void main() {
  expect(childParticle2.progress, 0.5);
  expect(particle.children.length, 1);
  });
+
+ testWithFlameGame(
+ 'generate particles without parent lifespan applied to children',
+ (game) async {
+ const particlesCount = 15;
+ final component = ParticleSystemComponent(
+ particle: Particle.generate(
+ count: particlesCount,
+ generator: (i) {
+ return CircleParticle(
+ paint: Paint()..color = Colors.red,
+ lifespan: 5,
+ );
+ },
+ applyLifespanToChildren: false,
+ lifespan: 10,
+ ),
+ );
+
+ game.add(component);
+ await game.ready();
+ game.update(1);
+
+ expect(component.particle!.progress, 0.1);
+ final children1 = (component.particle! as ComposedParticle).children;
+ expect(children1.length, particlesCount);
+ for (final child in children1) {
+ expect(child.progress, 0.2);
+ }
+
+ game.update(1);
+
+ expect(component.particle!.progress, 0.2);
+ final children2 = (component.particle! as ComposedParticle).children;
+ expect(children2.length, particlesCount);
+ for (final child in children2) {
+ expect(child.progress, 0.4);
+ }
+ },
+ );
  });
 }