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feat: Add a method to adapt the camera bounds to the world (#2769)
This PR adds a method to the CameraComponent class that allows it to set its bounds according to the current world. In fact, this was the behavior of the old camera object.
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packages/flame/lib/src/camera/behaviors/viewport_aware_bounds_behavior.dart
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,117 @@ | ||
| import 'dart:math'; | ||
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| import 'package:flame/extensions.dart'; | ||
| import 'package:flame/src/camera/behaviors/bounded_position_behavior.dart'; | ||
| import 'package:flame/src/camera/camera_component.dart'; | ||
| import 'package:flame/src/camera/viewfinder.dart'; | ||
| import 'package:flame/src/camera/viewport.dart'; | ||
| import 'package:flame/src/components/core/component.dart'; | ||
| import 'package:flame/src/components/mixins/parent_is_a.dart'; | ||
| import 'package:flame/src/experimental/geometry/shapes/circle.dart'; | ||
| import 'package:flame/src/experimental/geometry/shapes/rectangle.dart'; | ||
| import 'package:flame/src/experimental/geometry/shapes/rounded_rectangle.dart'; | ||
| import 'package:flame/src/experimental/geometry/shapes/shape.dart'; | ||
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| /// This behavior ensures that none of the viewport can go outside | ||
| /// of the bounds, when it is false only the viewfinder anchor is considered. | ||
| /// Note that it only works with [Rectangle], [RoundedRectangle] and [Circle] | ||
| /// shapes. | ||
| class ViewportAwareBoundsBehavior extends Component with ParentIsA<Viewfinder> { | ||
| Shape _boundsShape; | ||
| late Rect _visibleWorldRect; | ||
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| ViewportAwareBoundsBehavior({ | ||
| required Shape boundsShape, | ||
| }) : _boundsShape = boundsShape; | ||
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| @override | ||
| void onLoad() { | ||
| _visibleWorldRect = parent.visibleWorldRect; | ||
| parent.transform.scale.addListener(_updateCameraBoundsIfNeeded); | ||
| viewport.transform.scale.addListener(_updateCameraBoundsIfNeeded); | ||
| } | ||
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| @override | ||
| void onMount() { | ||
| super.onMount(); | ||
| _updateCameraBounds(); | ||
| } | ||
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| @override | ||
| void onRemove() { | ||
| viewport.transform.scale.removeListener(_updateCameraBoundsIfNeeded); | ||
| parent.transform.scale.removeListener(_updateCameraBoundsIfNeeded); | ||
| } | ||
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| /// Returns the bounds that do not take the viewport into account. | ||
| /// These bounds are automatically updated when [CameraComponent.setBounds] | ||
| /// is being called. | ||
| Shape get boundsShape => _boundsShape; | ||
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| /// Changes the original camera bounds. | ||
| /// This setter is used when you call [CameraComponent.setBounds]. | ||
| set boundsShape(Shape boundsShape) { | ||
| _boundsShape = boundsShape; | ||
| _updateCameraBounds(); | ||
| } | ||
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| /// Returns the camera viewport. | ||
| Viewport get viewport => parent.camera.viewport; | ||
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| /// Calls [_updateCameraBounds] if the [_visibleWorldRect] differs from | ||
| /// viewfinder visible world rect. | ||
| void _updateCameraBoundsIfNeeded() { | ||
| if (_visibleWorldRect != parent.visibleWorldRect) { | ||
| _updateCameraBounds(); | ||
| } | ||
| } | ||
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| /// Triggers an update of the current camera bounds. | ||
| void _updateCameraBounds() { | ||
| _visibleWorldRect = parent.visibleWorldRect; | ||
| final boundedBehavior = parent.firstChild<BoundedPositionBehavior>(); | ||
| boundedBehavior?.bounds = _calculateViewportAwareBounds(); | ||
| } | ||
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| /// This method calculates adapts the [_boundsShape] so that none | ||
| /// of the viewport can go outside of the bounds. | ||
| /// It returns the [_boundsShape] if it fails to calculates new bounds. | ||
| Shape _calculateViewportAwareBounds() { | ||
| final worldSize = Vector2( | ||
| _boundsShape | ||
| .support( | ||
| _boundsShape.nearestPoint( | ||
| _boundsShape.center + Vector2(1, 0), | ||
| ), | ||
| ) | ||
| .x, | ||
| _boundsShape | ||
| .support( | ||
| _boundsShape.nearestPoint( | ||
| _boundsShape.center + Vector2(0, 1), | ||
| ), | ||
| ) | ||
| .y, | ||
| ); | ||
| final halfViewportSize = viewport.size / 2; | ||
| if (_boundsShape is Rectangle) { | ||
| return Rectangle.fromCenter( | ||
| center: _boundsShape.center, | ||
| size: worldSize - halfViewportSize, | ||
| ); | ||
| } else if (_boundsShape is RoundedRectangle) { | ||
| final halfSize = (worldSize - halfViewportSize) / 2; | ||
| return RoundedRectangle.fromPoints( | ||
| _boundsShape.center - halfSize, | ||
| _boundsShape.center + halfSize, | ||
| (_boundsShape as RoundedRectangle).radius, | ||
| ); | ||
| } else if (_boundsShape is Circle) { | ||
| return Circle( | ||
| _boundsShape.center, | ||
| worldSize.x - max(halfViewportSize.x, halfViewportSize.y), | ||
| ); | ||
| } | ||
| return _boundsShape; | ||
| } | ||
| } |
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29 changes: 29 additions & 0 deletions
29
packages/flame/test/camera/behaviors/viewport_aware_bounds_behavior_test.dart
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,29 @@ | ||
| import 'package:flame/camera.dart'; | ||
| import 'package:flame/experimental.dart'; | ||
| import 'package:flame_test/flame_test.dart'; | ||
| import 'package:flutter_test/flutter_test.dart'; | ||
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| void main() { | ||
| group('ViewportAwareBoundsBehavior', () { | ||
| testWithFlameGame('setBounds considering viewport', (game) async { | ||
| final world = World()..addToParent(game); | ||
| final camera = CameraComponent(world: world)..addToParent(game); | ||
| await game.ready(); | ||
| final bounds = Rectangle.fromLTRB(0, 0, 400, 50); | ||
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| camera.setBounds(bounds); | ||
| game.update(0); | ||
| expect((_getBounds(camera) as Rectangle).toRect(), bounds.toRect()); | ||
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| camera.setBounds(bounds, considerViewport: true); | ||
| game.update(0); | ||
| expect( | ||
| (_getBounds(camera) as Rectangle).toRect(), | ||
| Rectangle.fromLTRB(200.0, -100.0, 200.0, 150.0).toRect(), | ||
| ); | ||
| }); | ||
| }); | ||
| } | ||
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| Shape _getBounds(CameraComponent camera) => | ||
| camera.viewfinder.firstChild<BoundedPositionBehavior>()!.bounds; |