Rough metals and rough clay: the source

since 0.8.0 Shading and materials
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: metals (line 34), clay (line 50), light (line 65), settings (line 73).
1/// Gold from polished to rough above, grey clay from half rough to fully rough
2/// below: the two frame settings that keep rough surfaces from losing light.
3///
4/// Quoted by `rough_surfaces.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 RoughSurfacesDemo extends ShowcaseDemo {
bool compensate = true;
bool orenNayar = true;

static const List<double> _metalRoughness = <double>[0.1, 0.3, 0.5, 0.7, 0.9];
static const List<double> _clayRoughness = <double>[0.5, 0.75, 1.0];

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 7.0
    ..yaw = 0.0
    ..pitch = 0.05;
}

@override
Scene build(DemoContext context) {
  final DeviceMesh ball = DeviceMesh.upload(
    context.device,
    SphereShape(radius: 0.5, segments: 48, rings: 24).build(),
  );
  final Scene scene = Scene()..ambientIntensity = 0.1;

  for (var i = 0; i < _metalRoughness.length; i++) {
    scene.add(
      MeshNode(
        ball,
        Material(
          name: 'gold ${_metalRoughness[i]}',
          lighting: LightingModel.pbr,
          baseColor: Vector4(1.0, 0.78, 0.34, 1.0),
          metallic: 1.0,
          roughness: _metalRoughness[i],
        ),
        name: 'gold',
      )..setPosition((i - 2) * 1.15, 0.65, 0.0),
    );
  }

  for (var i = 0; i < _clayRoughness.length; i++) {
    scene.add(
      MeshNode(
        ball,
        Material(
          name: 'clay ${_clayRoughness[i]}',
          lighting: LightingModel.pbr,
          baseColor: Vector4(0.42, 0.42, 0.42, 1.0),
          roughness: _clayRoughness[i],
        ),
        name: 'clay',
      )..setPosition((i - 1) * 1.15, -0.65, 0.0),
    );
  }

  return scene..add(
    LightNode(name: 'key', intensity: 3.0)
      ..setLocalForward(Vector3(-0.3, -0.4, -1.0).normalized()),
  );
}

@override
RenderSettings settings(DemoContext context) => RenderSettings(
  energyCompensation: compensate,
  diffuseModel: orenNayar ? DiffuseModel.eon : DiffuseModel.lambert,
);

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  ToggleControl(
    'Energy compensation',
    value: () => compensate,
    onChanged: (bool v) => compensate = v,
  ),
  ToggleControl(
    'Energy-preserving diffuse',
    value: () => orenNayar,
    onChanged: (bool v) => orenNayar = v,
  ),
];

@override
void verify(Scene scene, FrameResult frame) {
  final FramePass? pass = frame.passes
      .where((FramePass p) => p.name == 'scene')
      .firstOrNull;
  final int spheres = _metalRoughness.length + _clayRoughness.length;
  if (pass == null || pass.drawCalls < spheres) {
    throw StateError('the scene pass did not draw all $spheres spheres');
  }
}
101}