Directional, point and spot lights: the source

since 0.2.0 Shading and materials
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: directional (line 56), point (line 62), spot (line 69), live (line 87), check (line 111).
1/// The three punctual light types: directional, point and spot, each with
2/// its own sphere so the difference is easy to read.
3///
4/// Quoted by `punctual_lights.md` and shown whole in the Source tab.
5library;

7import 'dart:math' as math;

9import 'package:flutter3d/flutter3d.dart';
10import 'package:flutter3d_showcase/src/demo/demo.dart';
11import 'package:vector_math/vector_math.dart';

13final class PunctualLightsDemo extends ShowcaseDemo {
double pointRange = 4.0;
double spotOuterDegrees = 25.0;

late final LightNode _point;
late final LightNode _spot;

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 7.0
    ..pitch = 0.25;
}

@override
Scene build(DemoContext context) {
  final DeviceMesh sphere = DeviceMesh.upload(
    context.device,
    SphereShape(segments: 32, rings: 16).build(),
  );
  final Scene scene = Scene()
    ..add(
      MeshNode(
        sphere,
        Material(baseColor: Vector4(0.8, 0.8, 0.8, 1.0)),
        name: 'sun ball',
      )..setPosition(-2.2, 0.0, 0.0),
    )
    ..add(
      MeshNode(
        sphere,
        Material(baseColor: Vector4(0.8, 0.8, 0.8, 1.0)),
        name: 'point ball',
      )..setPosition(0.0, 0.0, 0.0),
    )
    ..add(
      MeshNode(
        sphere,
        Material(baseColor: Vector4(0.8, 0.8, 0.8, 1.0)),
        name: 'spot ball',
      )..setPosition(2.2, 0.0, 0.0),
    );

  final LightNode sun = LightNode(
    name: 'sun',
    type: LightType.directional,
    intensity: 2.0,
  )..setLocalForward(Vector3(-0.3, -0.6, -0.7));

  _point = LightNode(
    name: 'lamp',
    type: LightType.point,
    intensity: 6.0,
    range: pointRange,
  )..setPosition(0.0, 1.6, 1.2);

  _spot = LightNode(
    name: 'torch',
    type: LightType.spot,
    intensity: 10.0,
    range: 6.0,
    innerConeAngle: 0.0,
    outerConeAngle: spotOuterDegrees * math.pi / 180.0,
  )..setPosition(2.2, 2.2, 1.6);
  _spot.lookAt(Vector3(2.2, 0.0, 0.0));

  return scene
    ..add(sun)
    ..add(_point)
    ..add(_spot);
}

@override
void update(DemoContext context, double dt) {
  _point.range = pointRange;
  _spot.outerConeAngle = spotOuterDegrees * math.pi / 180.0;
}

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  SliderControl(
    'Point range',
    min: 1,
    max: 10,
    value: () => pointRange,
    onChanged: (double v) => pointRange = v,
  ),
  SliderControl(
    'Spot cone (degrees)',
    min: 5,
    max: 60,
    value: () => spotOuterDegrees,
    onChanged: (double v) => spotOuterDegrees = v,
  ),
];

@override
void verify(Scene scene, FrameResult frame) {
  final Set<LightType> types = <LightType>{
    for (final LightNode light in scene.lights) light.type,
  };
  if (types.length != 3) {
    throw StateError('expected all three punctual types, found $types');
  }
  if (_point.range != pointRange) {
    throw StateError('the point light range did not track the slider');
  }
  if (frame.drawCalls < 3) {
    throw StateError('not every ball was drawn');
  }
}
124}