Soft shadows: the source

since 0.7.0 Shadows
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: casters (line 41), lights (line 78), settings (line 105).
1/// A penumbra that widens with distance: sharp where a shadow starts, soft
2/// where it has travelled.
3///
4/// Quoted by `soft_shadows.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 SoftShadowsDemo extends ShowcaseDemo {
double sunRadius = 0.05;
double lampRadius = 0.3;
int lightChoice = 0;

late final LightNode _sun;
late final LightNode _lamp;

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 8.0
    ..pitch = 0.75
    ..yaw = 0.9;
}

@override
Scene build(DemoContext context) {
  final Material stone = Material(
    name: 'stone',
    baseColor: Vector4(0.78, 0.76, 0.72, 1.0),
    roughness: 0.9,
    doubleSided: true,
  );
  final Material clay = Material(
    name: 'clay',
    baseColor: Vector4(0.85, 0.45, 0.3, 1.0),
    roughness: 0.7,
  );

  final Scene scene = Scene()
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          const PlaneShape(width: 12, depth: 12).build(),
        ),
        stone,
        name: 'ground',
      ),
    )
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          const CylinderShape(
            radiusTop: 0.12,
            radiusBottom: 0.12,
            height: 3.0,
            segments: 16,
          ).build(),
        ),
        clay,
        name: 'pole',
      )..setPosition(-1.5, 1.5, 0.0),
    )
    ..add(
      MeshNode(
        DeviceMesh.upload(
          context.device,
          CuboidShape(size: Vector3(1.6, 0.15, 1.6)).build(),
        ),
        clay,
        name: 'slab',
      )..setPosition(1.5, 1.6, 0.0),
    );

  _sun = LightNode(name: 'sun', intensity: 3.0, castsShadow: true)
    ..setLocalForward(Vector3(-0.55, -0.7, -0.35));
  _lamp = LightNode(
    name: 'lamp',
    type: LightType.point,
    intensity: 60.0,
    range: 20.0,
  )..setPosition(2.5, 3.2, 2.5);
  scene
    ..add(_sun)
    ..add(_lamp);
  return scene;
}

@override
void update(DemoContext context, double dt) {
  final bool lamp = lightChoice == 1;
  _sun
    ..castsShadow = !lamp
    ..intensity = lamp ? 0.0 : 3.0;
  _lamp
    ..castsShadow = lamp
    ..intensity = lamp ? 60.0 : 0.0;
}

@override
RenderSettings settings(DemoContext context) => RenderSettings(
  shadows: ShadowSettings(
    cascades: 1,
    resolution: 1024,
    cubeResolution: 256,
    directionalLightRadius: sunRadius,
    pointLightRadius: lampRadius,
  ),
);

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  ChoiceControl(
    'Light',
    options: const <String>['Sun', 'Lamp'],
    index: () => lightChoice,
    onChanged: (int i) => lightChoice = i,
  ),
  SliderControl(
    'Sun size',
    min: 0,
    max: 0.2,
    value: () => sunRadius,
    onChanged: (double v) => sunRadius = v,
    format: (double v) => '${(v * 57.29578).toStringAsFixed(1)}°',
  ),
  SliderControl(
    'Lamp size',
    min: 0,
    max: 0.6,
    value: () => lampRadius,
    onChanged: (double v) => lampRadius = v,
    format: (double v) => '${v.toStringAsFixed(2)} 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 to soften');
  }
  if (frame.shadowsDenied > 0) {
    throw StateError('the light was denied its shadow');
  }
}
149}