flame/doc/examples/parallax/lib/main_auto_loading.dart

import 'package:flame/components.dart';
import 'package:flame/flame.dart';
import 'package:flame/game.dart';
import 'package:flame/parallax.dart';
import 'package:flutter/material.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Flame.device.fullScreen();
  runApp(
    GameWidget(
      game: MyGame(),
    ),
  );
}

class MyGame extends BaseGame {
  @override
  Future<void> onLoad() async {
    add(MyParallaxComponent());
  }
}

class MyParallaxComponent extends ParallaxComponent with HasGameRef<MyGame> {
  @override
  Future<void> onLoad() async {
    parallax = await gameRef.loadParallax(
      [
        'bg.png',
        'mountain-far.png',
        'mountains.png',
        'trees.png',
        'foreground-trees.png',
      ],
      baseVelocity: Vector2(20, 0),
      velocityMultiplierDelta: Vector2(1.8, 1.0),
    );
  }
}