Procedural shapes: the source

since 0.1.0 Scene and geometry
Open the live demo · Read the guide · View on GitHub
Regions the guide quotes: descriptions (line 22), build (line 41), lighting (line 68), check (line 86).
1/// Five meshes generated from shape values without loading an asset.
2library;

4import 'package:flutter3d/flutter3d.dart';
5import 'package:flutter3d_showcase/src/demo/demo.dart';
6import 'package:vector_math/vector_math.dart';

8final class ProceduralShapesDemo extends ShowcaseDemo {
final List<MeshNode> _shapes = <MeshNode>[];

@override
void configureView(DemoContext context) {
  context.orbit
    ..distance = 11.0
    ..pitch = 0.25
    ..yaw = 0.12;
  context.orbit.target.setValues(0.0, 0.35, 0.0);
}

@override
Scene build(DemoContext context) {
  final List<(String, Shape)> descriptions = <(String, Shape)>[
    ('cuboid', CuboidShape(size: Vector3(1.4, 1.4, 1.4))),
    ('sphere', const SphereShape(radius: 0.8, segments: 32, rings: 16)),
    (
      'torus',
      const TorusShape(
        radius: 0.58,
        tubeRadius: 0.24,
        segments: 40,
        tubeSegments: 18,
      ),
    ),
    (
      'capsule',
      const CapsuleShape(radius: 0.45, height: 0.8, segments: 32, rings: 8),
    ),
    ('disc', const DiscShape(radius: 0.9, innerRadius: 0.28, segments: 40)),
  ];

  final Scene scene = Scene()
    ..ambientColor = Vector3(0.55, 0.62, 0.78)
    ..ambientIntensity = 0.16;
  for (var i = 0; i < descriptions.length; i++) {
    final (String name, Shape shape) = descriptions[i];
    final MeshData data = shape.build();
    final Material material = Material(
      name: '$name material',
      baseColor: Vector4(
        0.28 + i * 0.12,
        0.68 - i * 0.07,
        0.82 - i * 0.1,
        1.0,
      ),
      roughness: 0.42,
      metallic: i == 2 ? 0.55 : 0.05,
      doubleSided: name == 'disc',
    );
    final MeshNode node = MeshNode(
      DeviceMesh.upload(context.device, data),
      material,
      name: name,
    )..setPosition((i - 2) * 2.0, name == 'disc' ? 0.25 : 0.85, 0.0);
    _shapes.add(node);
    scene.add(node);
  }

  scene
    ..add(
      LightNode(name: 'key', intensity: 3.4)
        ..setLocalForward(Vector3(-0.45, -0.8, -0.38)),
    )
    ..add(
      LightNode(
        type: LightType.point,
        intensity: 10.0,
        range: 12.0,
        name: 'fill',
      )..setPosition(-3.0, 3.5, 3.0),
    );
  return scene;
}

@override
void verify(Scene scene, FrameResult frame) {
  final Set<String?> names = <String?>{
    for (final MeshNode node in _shapes) node.name,
  };
  const Set<String> expected = <String>{
    'cuboid',
    'sphere',
    'torus',
    'capsule',
    'disc',
  };
  if (_shapes.length != expected.length ||
      !names.containsAll(expected) ||
      frame.drawCalls < expected.length) {
    throw StateError('not every procedural shape was drawn');
  }
}
102}