mirror of
https://github.com/flame-engine/flame.git
synced 2025-11-03 12:28:03 +08:00
d2a8fe01fa
This PR adds a new mixin on Component. When attached to a component, it allows scaling the delta time of that component as well as all its children by a non-negative factor. The idea is to allows slowing down or speeding up the gameplay by change the scaling factor. Note: This approach works only for framerate independent game logic. Code in update() that is not dependent on delta time will remain unaffected by time scale.
100 lines
2.8 KiB
Dart
100 lines
2.8 KiB
Dart
import 'package:flame/components.dart';
|
|
import 'package:flame/game.dart';
|
|
import 'package:flame_test/flame_test.dart';
|
|
import 'package:test/test.dart';
|
|
|
|
void main() {
|
|
group('HasTimeScale', () {
|
|
testWithGame<_GameWithTimeScale>(
|
|
'delta time scales correctly',
|
|
_GameWithTimeScale.new,
|
|
(game) async {
|
|
final component = _MovingComponent();
|
|
await game.add(component);
|
|
await game.ready();
|
|
const stepTime = 10.0;
|
|
var distance = 0.0;
|
|
final offset = stepTime * component.speed;
|
|
|
|
game.timeScale = 0.5;
|
|
distance = component.x;
|
|
game.update(stepTime);
|
|
expect(component.x, distance + game.timeScale * offset);
|
|
|
|
game.timeScale = 1.0;
|
|
distance = component.x;
|
|
game.update(stepTime);
|
|
expect(component.x, distance + game.timeScale * offset);
|
|
|
|
game.timeScale = 1.5;
|
|
distance = component.x;
|
|
game.update(stepTime);
|
|
expect(component.x, distance + game.timeScale * offset);
|
|
|
|
game.timeScale = 2.0;
|
|
distance = component.x;
|
|
game.update(stepTime);
|
|
expect(component.x, distance + game.timeScale * offset);
|
|
},
|
|
);
|
|
|
|
testWithGame(
|
|
'cascading time scale',
|
|
_GameWithTimeScale.new,
|
|
(game) async {
|
|
final component1 = _ComponentWithTimeScale();
|
|
final component2 = _MovingComponent();
|
|
await component1.add(component2);
|
|
await game.add(component1);
|
|
await game.ready();
|
|
const stepTime = 10.0;
|
|
var distance = 0.0;
|
|
final offset = stepTime * component2.speed;
|
|
|
|
game.timeScale = 0.5;
|
|
component1.timeScale = 0.5;
|
|
distance = component2.x;
|
|
game.update(stepTime);
|
|
expect(
|
|
component2.x,
|
|
distance + game.timeScale * component1.timeScale * offset,
|
|
);
|
|
|
|
game.timeScale = 1.0;
|
|
distance = component2.x;
|
|
game.update(stepTime);
|
|
expect(
|
|
component2.x,
|
|
distance + game.timeScale * component1.timeScale * offset,
|
|
);
|
|
|
|
component1.timeScale = 1.5;
|
|
distance = component2.x;
|
|
game.update(stepTime);
|
|
expect(
|
|
component2.x,
|
|
distance + game.timeScale * component1.timeScale * offset,
|
|
);
|
|
|
|
game.timeScale = 2.0;
|
|
distance = component2.x;
|
|
game.update(stepTime);
|
|
expect(
|
|
component2.x,
|
|
distance + game.timeScale * component1.timeScale * offset,
|
|
);
|
|
},
|
|
);
|
|
});
|
|
}
|
|
|
|
class _GameWithTimeScale extends FlameGame with HasTimeScale {}
|
|
|
|
class _ComponentWithTimeScale extends Component with HasTimeScale {}
|
|
|
|
class _MovingComponent extends PositionComponent {
|
|
final speed = 1.0;
|
|
@override
|
|
void update(double dt) => position.setValues(position.x + speed * dt, 0);
|
|
}
|