The scene surface and its status screens: the source

since 0.7.0 Widgets and the rest

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

Regions the guide quotes: scene (line 18), surface (line 37), failure (line 53).

1/// The widget every viewport in this app is built from: renders a scene
2/// once a frame and hands the result to Flutter through `presentFrame`, and
3/// the screen an application shows when a renderer never opened at all.
4///
5/// Quoted by `scene_surface.md` and shown whole in the Source tab.
6library;

8import 'package:flutter/widgets.dart';
9import 'package:flutter3d/flutter3d.dart' hide Material;
10import 'package:flutter3d/flutter3d.dart' as f3d show Material;
11import 'package:flutter3d_app/flutter3d_app.dart';
12import 'package:flutter3d_showcase/src/demo/demo.dart';
13import 'package:vector_math/vector_math.dart';

15final class SceneSurfaceDemo extends ShowcaseDemo {
late Scene _scene;

@override
Scene build(DemoContext context) {
  final material = f3d.Material(
    name: 'ball',
    baseColor: Vector4(0.6, 0.7, 0.9, 1.0),
  );
  final ball = MeshNode(
    DeviceMesh.upload(context.device, SphereShape(segments: 24).build()),
    material,
  );
  _scene = Scene()
    ..add(ball)
    ..add(
      LightNode(name: 'sun', intensity: 3.0)
        ..setLocalForward(Vector3(-0.4, -1.0, -0.3)),
    );
  return _scene;
}

@override
Widget? customBody(BuildContext buildContext, DemoContext context) =>
    SceneSurface(
      renderer: context.renderer,
      scene: _scene,
      view: context.view,
      settings: () => const RenderSettings(),
      onBeforeFrame: () {},
      presentFrame: presentFrame,
    );

@override
void verify(Scene scene, FrameResult frame) {
  if (frame.drawCalls < 1) {
    throw StateError('the ball was not drawn');
  }
  // What an application shows instead, when the renderer never opened.
  final failure = DidNotStart(
    StateError('no shader bundle for this build'),
    explaining: 'run tool/build_shaders.sh first',
  );
  if (failure.explaining != 'run tool/build_shaders.sh first') {
    throw StateError('the explanation should be carried through as given');
  }
}
62}