Migration to the latest version of flame-engine packages for the final code sample of the "Building Games with Flutter" book

Big thanks to Paul Teale the author of the "Building Games with Flutter" book for the great content and the code samples. I have learned a lot from this book and I highly recommend it to anyone who wants to learn how to build games with Flutter.

Since the flame-engine is rapidly evolving, the code samples needs several updates that I've implemented in this repository. I'd like to describe them in this README file.

Versions of packages

Increased the version of the environment sdk to ">=3.0.0 <4.0.0".

The flame-engine dependencies versions are changed to the latest ones:

flame: ^1.8.0
flame_tiled: ^1.10.1
flame_audio: ^2.0.2
a_star_algorithm: ^0.3.0
shared_preferences: ^2.1.1

Replaced mixins

• Tappable to TapCallbacks
• Collidable to CollisionCallbacks
• HasDraggables to DragCallbacks.

Removed some not necessary mixins usage.

Replaced classes

• TapUpInfo to TapUpEvent, TapDownInfo to TapDownEvent, add TapCancelEvent to onTapCancel method. Changed their return type from bool to void.
• ParticleComponent to ParticleSystemComponent with particle named parameter.
• HitboxRectangle to RectangleHitbox, pass the collisionType argument with the CollisionType.passive value to its constructor.

Collision detection

Replaced argument type of the other object from Collidable to PositionComponent and added the call of super.onCollision(points, other); in the onCollision overridden methods.

Replaced the addHitbox() with the add() method call in components.
For instance, in case of hit-box initialization for a component with the passive collision type:

collidableType = CollidableType.passive;
addHitbox(HitboxRectangle());

code is replaced to

add(RectangleHitbox(collisionType: CollisionType.passive));

and in case of hitbox for a component with the active collision type:

addHitbox(HitboxRectangle(relation: Vector2(0.7, 0.7))..relativeOffset = Vector2(0.0, 0.1));

code is replaced with

add(RectangleHitbox.relative(Vector2(0.7, 0.7), parentSize: size, position: Vector2(0.0, 0.1)));

World and Camera

Applied usage of the World and Camera components in main.dart.
Added custom World class with HasCollisionDetection mixin.

Camera initialization logic:

camera.speed = 1;
camera.followComponent(george, worldBounds: Rect.fromLTWH(gameScreenBounds.left, gameScreenBounds.top, 1600, 1600));

is changed to the new calculation of camera bounds:

final camera = CameraComponent(world: world);
camera.follow(george);
Rectangle rect = Rectangle.fromLTRB(
    size.x / 2, size.y / 2, 1600 - size.x / 2, 1600 - size.y / 2);
camera.setBounds(rect);
camera.viewport.add(hud);
add(camera);

As you can see, the Hud component is added to the camera viewport now. Fixed the X coordinate for the Health text in the Hud class.

TiledMap

Changed logic of reading object group from layer:

final water = tiledMap.tileMap.getObjectGroupFromLayer('Water');
final enemies = tiledMap.tileMap.getObjectGroupFromLayer('Enemies');

to

final water = tiledMap.tileMap.getLayer<ObjectGroup>('Water')!;
final enemies = tiledMap.tileMap.getLayer<ObjectGroup>('Enemies')!;

Further improvement notes

I've noticed few issues that could fixed in the future. I didn't want to fix them now, because the main goal of this repository is to show flame-engine migration steps.

I'm new in flutter and flame-engine, so if you find any mistakes in this repository, please let me know by PR or issue.

I hope this repository will be useful for someone else.