Doors, lifts and buttons: the source

since 0.4.0 or earlier Simulation, audio and XR
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: live (line 41), press-live (line 114), world (line 146), wire (line 149), press (line 171).
1/// Doors, lifts and buttons: one machine that travels between two places, and
2/// a switch that relays an activation to it by name.
3///
4/// Quoted by `level_mechanisms.md` and shown whole in the Source tab.
5library;

7import 'package:flutter3d/flutter3d.dart' hide Material;
8import 'package:flutter3d_showcase/src/demo/demo.dart';
9import 'package:flutter3d_showcase/src/demo/scene_kit.dart';
10import 'package:flutter3d_sim/flutter3d_sim.dart';
11import 'package:vector_math/vector_math.dart';

13final class LevelMechanismsDemo extends ShowcaseDemo {
late final String _report;

bool automatic = true;
bool _pressAsked = false;

late final MechanismWorld _mechanisms;
late final Door _door;
late final Collider _doorCollider;
late final MeshNode _doorNode;
late final MeshNode _buttonNode;
late final BarGauge _progress;
double _clock = 0.0;
double _lit = 0.0;

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 9.0
    ..pitch = 0.3
    ..yaw = 0.4;
  context.orbit.target.setValues(2.5, 1.2, 0.0);
}

@override
Scene build(DemoContext context) {
  _report = _run();

  // The same door and button, running: the door's collider is what the
  // mechanism moves, and the picture follows it.
  final CollisionWorld world = CollisionWorld();
  _mechanisms = MechanismWorld(world);
  _doorCollider = world.addBox(Vector3(5, 1, 0), Vector3(1, 2, 0.2));
  _door = _mechanisms.add(
    Door(
      name: 'north-door',
      collider: _doorCollider,
      travel: Vector3(0, 2, 0),
    ),
  );
  _mechanisms.add(
    Button(
      name: 'door-button',
      target: 'north-door',
      collider: world.addBox(Vector3(0, 1, 0), Vector3(0.3, 0.3, 0.3)),
    ),
  );

  _doorNode = blockNode(
    context,
    'door',
    Vector3(1.0, 2.0, 0.2),
    Vector4(0.65, 0.42, 0.3, 1.0),
    at: Vector3(5.0, 1.0, 0.0),
  );
  _buttonNode = blockNode(
    context,
    'button',
    Vector3(0.3, 0.3, 0.3),
    Vector4(0.8, 0.2, 0.2, 1.0),
    at: Vector3(0.0, 1.0, 0.0),
  );
  _progress = BarGauge(
    context,
    'progress',
    Vector4(0.9, 0.75, 0.3, 1.0),
    Vector3(7.0, 0.0, 0.0),
    height: 2.0,
    vertical: true,
  );
  return sceneOf(<SceneNode>[
    floorNode(context, width: 12.0, depth: 6.0),
    // The frame the door slides up out of, and the wall beside it.
    blockNode(
      context,
      'wall left',
      Vector3(4.5, 3.0, 0.4),
      Vector4(0.5, 0.5, 0.52, 1.0),
      at: Vector3(2.75, 1.5, 0.0),
    ),
    blockNode(
      context,
      'wall right',
      Vector3(1.5, 3.0, 0.4),
      Vector4(0.5, 0.5, 0.52, 1.0),
      at: Vector3(5.75 + 0.25, 1.5, 0.0),
    ),
    _doorNode,
    _buttonNode,
    ..._progress.nodes,
  ]);
}

@override
void update(DemoContext context, double dt) {
  _clock += dt;
  if (automatic && _clock > 2.0 && (_clock - 2.0) % 8.0 < dt) {
    _pressAsked = true;
  }
  if (_pressAsked) {
    _pressAsked = false;
    _mechanisms.activate('door-button', const Activation());
    _lit = 1.0;
  }
  _mechanisms.step(dt);
  _lit = (_lit - dt * 1.5).clamp(0.0, 1.0);
  _doorNode.setPositionFrom(_doorCollider.position);
  _progress.set(_door.progress);
  _buttonNode.material.baseColor.setValues(
    0.8 - 0.6 * _lit,
    0.2 + 0.65 * _lit,
    0.2,
    1.0,
  );
}

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  ToggleControl(
    'Press the button',
    value: () => false,
    onChanged: (bool v) {
      if (v) _pressAsked = true;
    },
  ),
  ToggleControl(
    'Press it for me',
    value: () => automatic,
    onChanged: (bool v) => automatic = v,
  ),
];

static String _run() {
  final world = CollisionWorld();
  final mechanisms = MechanismWorld(world);

  final doorCollider = world.addBox(Vector3(5, 1, 0), Vector3(1, 2, 0.2));
  final door = mechanisms.add(
    Door(
      name: 'north-door',
      collider: doorCollider,
      travel: Vector3(0, 2, 0),
    ),
  );
  final buttonCollider = world.addBox(
    Vector3(0, 1, 0),
    Vector3(0.3, 0.3, 0.3),
  );
  mechanisms.add(
    Button(
      name: 'door-button',
      target: 'north-door',
      collider: buttonCollider,
    ),
  );

  final beforeProgress = door.progress;

  mechanisms.activate('door-button', const Activation());
  for (var i = 0; i < 180; i++) {
    mechanisms.step(1 / 60);
  }

  return 'the door started at progress ${beforeProgress.toStringAsFixed(2)}\n'
      'after pressing the button and stepping three seconds, it is at '
      '${door.progress.toStringAsFixed(2)}, state ${door.state.name}';
}

@override
void verify(Scene scene, FrameResult frame) {
  if (frame.drawCalls < 1) {
    throw StateError('the door marker was not drawn');
  }
  if (!_report.contains('started at progress 0.00')) {
    throw StateError('a door should start closed');
  }
  if (!_report.contains('is at 1.00, state open')) {
    throw StateError(
      'pressing the button should open the door within '
      'three seconds',
    );
  }
}
196}