feat: ⚡particles ⚡

lib/components/particle_component.dart

@@ -0,0 +1,80 @@
+import 'dart:ui';
+
+import 'package:flame/components/particles/composed_particle.dart';
+import 'package:flutter/foundation.dart';
+
+import '../time.dart';
+import 'component.dart';
+
+/// A function which returns [Particle] when called
+typedef ParticleGenerator = Particle Function(int);
+
+/// Base class implementing common behavior for all the particles.
+///
+/// Intention is to follow same "Extreme Composability" style
+/// as across the whole Flutter framework, so each type of particle implements
+/// some particular behavior which then could be nested and combined together
+/// to create specifically required experience.
+abstract class Particle extends Component {
+
+  /// Generates given amount of particles,
+  /// combining them into one [ComposedParticle]
+  /// Useful for procedural particle generation.
+  static Particle generate({
+    int count = 10, 
+    @required ParticleGenerator generator,
+    double lifespan,
+    Duration duration,
+  }) {
+    return ComposedParticle(
+      lifespan: lifespan,
+      duration: duration,
+      children: List<Particle>.generate(count, generator),
+    );
+  }
+  
+  Timer _timer;
+  bool _shouldBeDestroyed = false;
+
+  Particle({
+    /// Particle lifespan in [Timer] format,
+    /// double in seconds with microsecond precision
+    double lifespan,
+
+    /// Another way to set lifespan, using Flutter
+    /// [Duration] class
+    Duration duration,
+  }) {
+    /// Either [double] lifespan or [Duration] duration,
+    /// defaulting to 500 milliseconds of life (or .5, in [Timer] double)
+    lifespan = lifespan ??
+        (duration ?? const Duration(milliseconds: 500)).inMicroseconds /
+            Duration.microsecondsPerSecond;
+
+    setLifespan(lifespan);
+  }
+
+  @override
+  bool destroy() => _shouldBeDestroyed;
+  double get progress => _timer.progress;
+
+  @override
+  void render(Canvas canvas) {
+    // Do nothing by default
+  }
+
+  @override
+  void update(double dt) {
+    _timer.update(dt);
+
+    if (_timer.progress >= 1) {
+      _shouldBeDestroyed = true;
+    }
+  }
+
+  void setLifespan(double lifespan) {
+    _timer?.stop();
+    _timer = Timer(lifespan);
+    _timer.start();
+  }
+}