Use sync* for raytrace

packages/flame/lib/src/collisions/collision_detection.dart

@@ -96,17 +96,19 @@ abstract class CollisionDetection<T extends Hitbox<T>> {
  List<RaycastResult<T>>? out,
  });
 
- /// Gives back all hitboxes and intersection points the ray hits.
+ /// Follows the ray and its reflections until [maxDepth] is reached and then
+ /// returns all hitboxes, intersection points, normals and reflection rays
+ /// (bundled in a list of [RaycastResult]s) from where the ray hits.
  ///
  /// [maxDepth] is how many times the ray should collide before returning a
- /// result, defaults to 100.
+ /// result, defaults to 10.
  ///
  /// If [out] is provided the [RaycastResult]s in that list be modified and
  /// returned with the result. If there are less objects in [out] than the
  /// result requires, the missing [RaycastResult] objects will be created.
- List<RaycastResult<T>> raytrace(
+ Iterable<RaycastResult<T>> raytrace(
  Ray2 ray, {
- double maxDepth = 100,
+ double maxDepth = 10,
  List<RaycastResult<T>>? out,
  });
 }

packages/flame/lib/src/collisions/standard_collision_detection.dart

@@ -130,11 +130,12 @@ class StandardCollisionDetection extends CollisionDetection<ShapeHitbox> {
  }
 
  @override
- List<RaycastResult<ShapeHitbox>> raytrace(
+ Iterable<RaycastResult<ShapeHitbox>> raytrace(
  Ray2 ray, {
- double maxDepth = 100,
+ double maxDepth = 10,
  List<RaycastResult<ShapeHitbox>>? out,
- }) {
+ }) sync* {
+ out?.forEach((e) => e.reset());
  final result = out ?? <RaycastResult<ShapeHitbox>>[];
  var currentRay = ray;
  for (var i = 0; i < maxDepth; i++) {
@@ -145,14 +146,11 @@ class StandardCollisionDetection extends CollisionDetection<ShapeHitbox> {
  currentRay = currentResult.reflectionRay!;
  if (!hasResultObject) {
  result.add(currentResult);
+ yield currentResult;
  }
  } else {
- for (var j = i; j < result.length; j++) {
- result[j].reset();
- }
  break;
  }
  }
- return result;
  }
 }

packages/flame/test/collisions/collision_detection_test.dart

@@ -1113,7 +1113,7 @@ void main() {
  )..add(CircleHitbox());
  await game.ensureAddAll([circle1, circle2]);
  final ray = Ray2(Vector2(0, 10), Vector2.all(1.0)..normalize());
- final results = game.collisionDetection.raytrace(ray);
+ final results = game.collisionDetection.raytrace(ray).toList();
  expect(results.length, 2);
  expect(results.every((e) => e.isActive), isTrue);
  expect(results.every((e) => e.isInsideHitbox), isFalse);
@@ -1146,7 +1146,7 @@ void main() {
  )..add(RectangleHitbox());
  await game.ensureAddAll([rectangle1, rectangle2]);
  final ray = Ray2(Vector2(0, 10), Vector2.all(1.0)..normalize());
- final results = game.collisionDetection.raytrace(ray);
+ final results = game.collisionDetection.raytrace(ray).toList();
  expect(results.length, 2);
  expect(results.every((e) => e.isActive), isTrue);
  expect(results.every((e) => e.isInsideHitbox), isFalse);
@@ -1156,7 +1156,8 @@ void main() {
  final reflectionRay1 = results[0].reflectionRay;
  expect(reflectionRay1?.origin, Vector2(10, 20));
  expect(reflectionRay1?.direction, Vector2(-1, 1)..normalize());
- final results2 = game.collisionDetection.raytrace(reflectionRay1!);
+ final results2 =
+ game.collisionDetection.raytrace(reflectionRay1!).toList();
  expect(results2.length, 1);
  // Second box
  expect(results[1].intersectionPoint, Vector2(-10, 40));
@@ -1176,8 +1177,8 @@ void main() {
  )..add(RectangleHitbox());
  await game.ensureAddAll([rectangle1, rectangle2]);
  final ray = Ray2(Vector2(20, 10), Vector2(1, 1)..normalize());
- final results = game.collisionDetection.raytrace(ray);
- expect(results.length, 100);
+ final results = game.collisionDetection.raytrace(ray).toList();
+ expect(results.length, 10);
  expect(results.every((e) => e.isActive), isTrue);
  expect(results[0].isInsideHitbox, isFalse);
  expect(results[1].isInsideHitbox, isTrue);
@@ -1187,8 +1188,9 @@ void main() {
  final reflectionRay1 = results[0].reflectionRay;
  expect(reflectionRay1?.origin, Vector2(30, 20));
  expect(reflectionRay1?.direction, Vector2(1, -1)..normalize());
- final results2 = game.collisionDetection.raytrace(reflectionRay1!);
- expect(results2.length, 100);
+ final results2 =
+ game.collisionDetection.raytrace(reflectionRay1!).toList();
+ expect(results2.length, 10);
  // Second box
  expect(results[1].intersectionPoint, Vector2(50, 0));
  expect(results[1].normal, Vector2(0, 1));