Stretched highlights: the source

since 0.8.0 Shading and materials
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: materials (line 28), mesh (line 45), live (line 66).
1/// One highlight round, the same highlight stretched: the anisotropy layer.
2///
3/// Quoted by `anisotropic_highlights.md` and shown whole in the Source tab.
4library;

6import 'dart:math' as math;

8import 'package:flutter3d/flutter3d.dart';
9import 'package:flutter3d_showcase/src/demo/demo.dart';
10import 'package:vector_math/vector_math.dart';

12final class AnisotropicHighlightsDemo extends ShowcaseDemo {
double strength = 0.9;
double rotation = 0.0;

late final Material _brushed;

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 3.4
    ..yaw = 0.0
    ..pitch = 0.1;
}

@override
Scene build(DemoContext context) {
  final Material plain = Material(
    name: 'plain',
    lighting: LightingModel.pbrLayered,
    baseColor: Vector4(0.8, 0.05, 0.05, 1.0),
    roughness: 0.3,
  );
  _brushed = Material(
    name: 'brushed',
    lighting: LightingModel.pbrLayered,
    baseColor: Vector4(0.8, 0.05, 0.05, 1.0),
    roughness: 0.3,
    extensions: MaterialExtensions(
      anisotropyStrength: strength,
      anisotropyRotation: rotation,
    ),
  );

  // A sphere from `SphereShape` carries a tangent at every vertex, running
  // around the sphere along its lines of latitude.
  final DeviceMesh ball = DeviceMesh.upload(
    context.device,
    SphereShape(radius: 0.5, segments: 48, rings: 24).build(),
  );

  return Scene()
    ..ambientIntensity = 0.15
    ..add(MeshNode(ball, plain, name: 'plain')..setPosition(-0.6, 0.0, 0.0))
    ..add(
      MeshNode(ball, _brushed, name: 'brushed')..setPosition(0.6, 0.0, 0.0),
    )
    ..add(
      LightNode(name: 'key', intensity: 3.0)
        ..setLocalForward(Vector3(-0.35, -0.45, -1.0).normalized()),
    );
}

@override
void update(DemoContext context, double dt) {
  _brushed.extensions = MaterialExtensions(
    anisotropyStrength: strength,
    anisotropyRotation: rotation,
  );
}

@override
List<DemoControl> controls(DemoContext context) => <DemoControl>[
  SliderControl(
    'Strength',
    min: 0,
    max: 1,
    value: () => strength,
    onChanged: (double v) => strength = v,
  ),
  SliderControl(
    'Rotation',
    min: 0,
    max: math.pi,
    value: () => rotation,
    onChanged: (double v) => rotation = v,
    format: (double v) => '${(v * 180 / math.pi).round()}°',
  ),
];

@override
void verify(Scene scene, FrameResult frame) {
  final MeshNode brushed = scene.meshes.firstWhere(
    (MeshNode m) => m.name == 'brushed',
  );
  if (!identical(brushed.material.lighting, LightingModel.pbrLayered)) {
    throw StateError('the brushed sphere is not on the layered model');
  }
  if ((brushed.material.extensions?.anisotropyStrength ?? 0.0) <= 0.0) {
    throw StateError('the brushed sphere has no anisotropy');
  }
  if (frame.drawCalls < 2) {
    throw StateError('the two spheres were not both drawn');
  }
}
106}