Manual exposure: the source

since 0.1.0 or earlier Shading and materials

Open the live demo · Read the guide · View on GitHub

Regions the guide quotes: scene (line 23), settings (line 46), check (line 62).

1/// `RenderSettings.exposure`: the linear multiplier the composite applies
2/// before the tone curve, set by hand rather than metered.
3///
4/// Quoted by `exposure.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 ExposureDemo extends ShowcaseDemo {
double exposure = 2.4;

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 5.0
    ..pitch = 0.1;
}

@override
Scene build(DemoContext context) {
  final Material lantern = Material(
    name: 'lantern',
    baseColor: Vector4(0.9, 0.85, 0.6, 1.0),
    emissive: Vector3(2.0, 1.7, 0.9),
  );
  final MeshNode box = MeshNode(
    DeviceMesh.upload(
      context.device,
      CuboidShape(size: Vector3(1.4, 1.4, 1.4)).build(),
    ),
    lantern,
    name: 'lantern',
  );
  return Scene()
    ..add(box)
    ..add(
      LightNode(name: 'sun', intensity: 1.5)
        ..setLocalForward(Vector3(-0.3, -0.6, -0.7)),
    );
}

@override
RenderSettings settings(DemoContext context) => RenderSettings(
  exposure: exposure,
);

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  SliderControl(
    'Exposure',
    min: 0.1,
    max: 4,
    value: () => exposure,
    onChanged: (double v) => exposure = v,
  ),
];

@override
void verify(Scene scene, FrameResult frame) {
  if ((frame.exposure - exposure).abs() > 1e-6) {
    throw StateError(
      'the frame was composited at ${frame.exposure}, not the '
      '$exposure this page asked for',
    );
  }
  if (frame.drawCalls < 1) {
    throw StateError('the lantern was not drawn');
  }
}
72}