Files
flame/lib/components/component.dart
2020-09-10 01:16:25 +02:00

61 lines
3.0 KiB
Dart

import 'dart:ui';
import 'package:flutter/painting.dart';
import 'package:vector_math/vector_math_64.dart';
/// This represents a Component for your game.
///
/// Components can be bullets flying on the screen, a spaceship or your player's fighter.
/// Anything that either renders or updates can be added to the list on [BaseGame]. It will deal with calling those methods for you.
/// Components also have other methods that can help you out if you want to overwrite them.
abstract class Component {
/// This method is called periodically by the game engine to request that your component updates itself.
///
/// The time [t] in seconds (with microseconds precision provided by Flutter) since the last update cycle.
/// This time can vary according to hardware capacity, so make sure to update your state considering this.
/// All components on [BaseGame] are always updated by the same amount. The time each one takes to update adds up to the next update cycle.
void update(double t);
/// Renders this component on the provided Canvas [c].
void render(Canvas c);
/// This is a hook called by [BaseGame] to let this component know that the screen (or flame draw area) has been update.
///
/// It receives the new size.
/// You can use the [Resizable] mixin if you want an implementation of this hook that keeps track of the current size.
void resize(Vector2 size) {}
/// Whether this component has been loaded yet. If not loaded, [BaseGame] will not try to render it.
///
/// Sprite based components can use this to let [BaseGame] know not to try to render when the [Sprite] has not been loaded yet.
/// Note that for a more consistent experience, you can pre-load all your assets beforehand with Flame.images.loadAll.
bool loaded() => true;
/// Whether this should be destroyed or not.
///
/// It will be called once per component per loop, and if it returns true, [BaseGame] will mark your component for deletion and remove it before the next loop.
bool destroy() => false;
/// Whether this component is HUD object or not.
///
/// HUD objects ignore the [BaseGame.camera] when rendered (so their position coordinates are considered relative to the device screen).
bool isHud() => false;
/// Render priority of this component. This allows you to control the order in which your components are rendered.
///
/// Components are always updated and rendered in the order defined by this number.
/// The smaller the priority, the sooner your component will be updated/rendered.
/// It can be any integer (negative, zero, or positive).
/// If two components share the same priority, they will probably be drawn in the order they were added.
int priority() => 0;
/// Called when the component has been added and preperad by the game instance.
///
/// This can be used to make initializations on your component as, when this method is called,
/// things like resize (and other mixins) are already set and usable.
void onMount() {}
/// Called right before the component is destroyed and removed from the game
void onDestroy() {}
}