Raycast, sweep and overlap: the source

since 0.5.0 Physics and particles
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: world (line 32), raycast (line 51), sweep (line 53), overlap (line 60), check (line 106).
1/// A raycast, a sweep and an overlap against the same small level, reported
2/// as text: three questions a `CollisionWorld` answers exactly rather than
3/// a picture asking you to take its word for it.
4///
5/// Quoted by `collision_queries.md` and shown whole in the Source tab.
6library;

8import 'package:flutter/widgets.dart';
9import 'package:flutter3d/flutter3d.dart';
10import 'package:flutter3d_physics/flutter3d_physics.dart';
11import 'package:flutter3d_showcase/src/demo/demo.dart';
12import 'package:vector_math/vector_math.dart';

14final class CollisionQueriesDemo extends ShowcaseDemo {
late final CollisionWorld _world;
late final Collider _pickup;

final RayHit _ray = RayHit();
final SweepHit _sweep = SweepHit();
final List<Collider> _overlapping = <Collider>[];

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 8.0
    ..pitch = 0.25
    ..yaw = 0.6;
}

@override
Scene build(DemoContext context) {
  _world = CollisionWorld();
  final Collider wall = _world.add(
    Collider(
      shape: CollisionBox(Vector3(2.0, 1.0, 0.2)),
      position: Vector3(0.0, 1.0, 0.0),
    ),
  );
  _pickup = _world.add(
    Collider(
      shape: CollisionSphere(0.4),
      position: Vector3(2.0, 0.5, 2.0),
      kind: ColliderKind.trigger,
    ),
  );
  // A trigger is not level geometry: `add` files anything that is not
  // `ColliderKind.static` as a mover, and a mover's grid cell is only
  // filled in when the world is asked to index it.
  _world.reindex();

  _world.raycast(Vector3(0.0, 1.0, 5.0), Vector3(0.0, 0.0, -1.0), 10.0, _ray);

  _world.sweep(
    CollisionBox(Vector3(0.3, 0.5, 0.3)),
    Vector3(0.0, 0.5, 3.0),
    Vector3(0.0, 0.0, -4.0),
    _sweep,
  );

  _world.overlap(
    CollisionBox(Vector3(0.1, 0.1, 0.1)),
    _pickup.position,
    _overlapping,
  );

  return Scene()
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          CuboidShape(size: Vector3(4.0, 2.0, 0.4)).build(),
        ),
        Material(name: 'wall', baseColor: Vector4(0.5, 0.5, 0.6, 1.0)),
        name: 'wall',
      )..setPositionFrom(wall.position),
    )
    ..add(
      LightNode(name: 'sun', intensity: 2.5)
        ..setLocalForward(Vector3(-0.3, -0.6, -0.4)),
    );
}

@override
Widget? customBody(BuildContext buildContext, DemoContext context) {
  String vec3(Vector3 v) =>
      '(${v.x.toStringAsFixed(2)}, ${v.y.toStringAsFixed(2)}, '
      '${v.z.toStringAsFixed(2)})';
  return Container(
    color: const Color(0xFF14161A),
    padding: const EdgeInsets.all(24),
    alignment: Alignment.topLeft,
    child: DefaultTextStyle(
      style: const TextStyle(color: Color(0xFFE8E8EC), fontSize: 15),
      child: Text(
        'raycast: ${_ray.hit ? 'hit at ${vec3(_ray.point)}' : 'miss'}\n'
        'sweep: ${_sweep.hit ? 'stopped at fraction ${_sweep.fraction.toStringAsFixed(3)}, '
                  'normal ${vec3(_sweep.normal)}' : 'clear'}\n'
        'overlap: ${_overlapping.length} collider(s) at the pickup',
      ),
    ),
  );
}

@override
void verify(Scene scene, FrameResult frame) {
  if (!_ray.hit || (_ray.distance - 4.8).abs() > 0.01) {
    throw StateError('the ray should meet the wall 4.8m out');
  }
  if (!_sweep.hit || _sweep.normal.z < 0.9) {
    throw StateError('the sweep should stop on the wall\'s near face');
  }
  if (_overlapping.length != 1 || !identical(_overlapping.first, _pickup)) {
    throw StateError('the overlap should find only the pickup');
  }
  if (frame.drawCalls < 1) {
    throw StateError('the wall did not reach the frame');
  }
}
119}