Shadow quality: the source

since 0.1.0 Shadows
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: ground (line 29), casters (line 47), sun (line 74), settings (line 83).
1/// The knobs that decide how good the sun's shadow looks: the size of its map,
2/// the bias that keeps it clean, how dark it is and how far it is fitted for.
3///
4/// Quoted by `shadow_settings.md` and shown whole in the Source tab.
5library;

7import 'package:flutter3d/flutter3d.dart';
8import 'package:flutter3d_showcase/src/demo/demo.dart';
9import 'package:vector_math/vector_math.dart';

11final class ShadowSettingsDemo extends ShowcaseDemo {
int resolutionChoice = 0;
double bias = 0.0015;
double strength = 1.0;
double viewDistance = 40.0;

static const List<int> _resolutions = <int>[256, 512, 1024, 2048];

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 9.0
    ..pitch = 0.6
    ..yaw = 0.6;
}

@override
Scene build(DemoContext context) {
  final Material stone = Material(
    name: 'stone',
    baseColor: Vector4(0.75, 0.73, 0.68, 1.0),
    roughness: 0.9,
    doubleSided: true,
  );
  final Scene scene = Scene()
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          const PlaneShape(width: 14, depth: 14).build(),
        ),
        stone,
        name: 'ground',
      ),
    );

  final Material clay = Material(
    name: 'clay',
    baseColor: Vector4(0.85, 0.45, 0.3, 1.0),
    roughness: 0.7,
  );
  scene
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          CuboidShape(size: Vector3(1.2, 2.4, 1.2)).build(),
        ),
        clay,
        name: 'column',
      )..setPosition(-1.5, 1.2, 0.0),
    )
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          SphereShape(radius: 0.8, segments: 32, rings: 16).build(),
        ),
        clay,
        name: 'ball',
      )..setPosition(1.5, 0.8, 0.5),
    );

  scene.add(
    LightNode(name: 'sun', intensity: 3.0, castsShadow: true)
      ..setLocalForward(Vector3(-0.5, -0.9, -0.4)),
  );
  return scene;
}

@override
RenderSettings settings(DemoContext context) => RenderSettings(
  shadows: ShadowSettings(
    cascades: 2,
    resolution: _resolutions[resolutionChoice],
    bias: bias,
    strength: strength,
    viewDistance: viewDistance,
  ),
);

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  ChoiceControl(
    'Map size',
    options: <String>[for (final int r in _resolutions) '$r'],
    index: () => resolutionChoice,
    onChanged: (int i) => resolutionChoice = i,
  ),
  SliderControl(
    'Bias',
    min: 0,
    max: 0.02,
    value: () => bias,
    onChanged: (double v) => bias = v,
    format: (double v) => v.toStringAsFixed(4),
  ),
  SliderControl(
    'Strength',
    min: 0,
    max: 1,
    value: () => strength,
    onChanged: (double v) => strength = v,
  ),
  SliderControl(
    'Distance',
    min: 3,
    max: 40,
    value: () => viewDistance,
    onChanged: (double v) => viewDistance = v,
    format: (double v) => '${v.round()} m',
  ),
];

@override
void verify(Scene scene, FrameResult frame) {
  if (!frame.passes.any((FramePass p) => p.name == 'directional shadows')) {
    throw StateError('the sun drew no shadow map');
  }
  if (frame.shadowCasters < 2) {
    throw StateError(
      'expected the column and the ball in the map, '
      'got ${frame.shadowCasters}',
    );
  }
}
137}