pinball/packages/pinball_components/lib/src/components/fire_effect.dart

import 'dart:math' as math;

import 'package:flame/components.dart';
import 'package:flame/extensions.dart';
import 'package:flame/particles.dart';
import 'package:flame_forge2d/flame_forge2d.dart' hide Particle;
import 'package:flutter/material.dart';

const _particleRadius = 0.25;

/// {@template fire_effect}
/// A [BodyComponent] which creates a fire trail effect using the given
/// parameters
/// {@endtemplate}
class FireEffect extends ParticleSystemComponent {
  /// {@macro fire_effect}
  FireEffect({
    required this.burstPower,
    required this.direction,
    Vector2? position,
  }) : super(
          position: position,
        );

  /// A [double] value that will define how "strong" the burst of particles
  /// will be.
  final double burstPower;

  /// Which direction the burst will aim.
  final Vector2 direction;

  @override
  Future<void> onLoad() async {
    await super.onLoad();

    final children = [
      ...List.generate(4, (index) {
        return CircleParticle(
          radius: _particleRadius,
          paint: Paint()..color = Colors.yellow.darken((index + 1) / 4),
        );
      }),
      ...List.generate(4, (index) {
        return CircleParticle(
          radius: _particleRadius,
          paint: Paint()..color = Colors.red.darken((index + 1) / 4),
        );
      }),
      ...List.generate(4, (index) {
        return CircleParticle(
          radius: _particleRadius,
          paint: Paint()..color = Colors.orange.darken((index + 1) / 4),
        );
      }),
    ];
    final random = math.Random();
    final spreadTween = Tween<double>(begin: -0.2, end: 0.2);

    particle = Particle.generate(
      count: math.max((random.nextDouble() * (burstPower * 10)).toInt(), 1),
      generator: (_) {
        final spread = Vector2(
          spreadTween.transform(random.nextDouble()),
          spreadTween.transform(random.nextDouble()),
        );
        final finalDirection = Vector2(direction.x, direction.y) + spread;
        final speed = finalDirection * (burstPower * 20);

        return AcceleratedParticle(
          lifespan: 5 / burstPower,
          position: Vector2.zero(),
          speed: speed,
          child: children[random.nextInt(children.length)],
        );
      },
    );
  }
}