Three Dart Fundamentals

three_dart Fundamentals

Iron Law

Always call renderer.dispose() in the widget dispose() method — failing to do so leaks the WebGL context, causing a crash after ~8 widget recreations on mobile.

Flutter uses the three_dart package — a Dart port of Three.js. API concepts are identical to Three.js; only syntax changes (Dart instead of JavaScript).

pubspec.yaml

dependencies:
  three_dart: ^0.0.15
  flutter_gl: ^0.0.10  # required — OpenGL bindings

Quick Start

import 'package:flutter/material.dart';
import 'package:three_dart/three_dart.dart' as THREE;
import 'package:three_dart_jsm/three_dart_jsm.dart' as THREE_JSM;

class ThreeDScene extends StatefulWidget {
  const ThreeDScene({super.key});
  @override
  State<ThreeDScene> createState() => _ThreeDSceneState();
}

class _ThreeDSceneState extends State<ThreeDScene> {
  late THREE.WebGLRenderer renderer;
  late THREE.Scene scene;
  late THREE.PerspectiveCamera camera;
  late THREE.Mesh cube;

  @override
  void initState() {
    super.initState();
    _initScene();
  }

  void _initScene() {
    scene = THREE.Scene();

    camera = THREE.PerspectiveCamera(75, 1.0, 0.1, 1000);
    camera.position.z = 5;

    final geometry = THREE.BoxGeometry(1, 1, 1);
    final material = THREE.MeshStandardMaterial({'color': 0x00ff00});
    cube = THREE.Mesh(geometry, material);
    scene.add(cube);

    scene.add(THREE.AmbientLight(0xffffff, 0.5));
    final dirLight = THREE.DirectionalLight(0xffffff, 1.0);
    dirLight.position.set(5, 5, 5);
    scene.add(dirLight);
  }

  void _animate(double delta) {
    cube.rotation.x += 0.01;
    cube.rotation.y += 0.01;
    renderer.render(scene, camera);
  }

  @override
  Widget build(BuildContext context) {
    return THREE_JSM.ThreeDartWidget(
      onSetupRenderer: (r) => renderer = r,
      onAnimate: _animate,
      scene: scene,
      camera: camera,
    );
  }

  @override
  void dispose() {
    renderer.dispose();
    super.dispose();
  }
}

Core Classes

Scene

final scene = THREE.Scene();
scene.background = THREE.Color(0x222222);
scene.fog = THREE.Fog(0x222222, 10, 100);

PerspectiveCamera

// PerspectiveCamera(fov, aspect, near, far)
final camera = THREE.PerspectiveCamera(75, width / height, 0.1, 1000);
camera.position.set(0, 2, 5);
camera.lookAt(THREE.Vector3(0, 0, 0));

WebGLRenderer

// Renderer is created by ThreeDartWidget — configure via onSetupRenderer
void onSetupRenderer(THREE.WebGLRenderer r) {
  renderer = r;
  renderer.setPixelRatio(window.devicePixelRatio);
  renderer.shadowMap.enabled = true;
  renderer.shadowMap.type = THREE.PCFSoftShadowMap;
}

Object3D Hierarchy

final group = THREE.Group();
group.add(mesh1);
group.add(mesh2);
scene.add(group);

// Transforms
mesh.position.set(1, 2, 3);
mesh.rotation.y = math.pi / 4;
mesh.scale.setScalar(2.0);

Key Difference from JS Three.js

See Also

• three-dart-geometry — geometry types and custom meshes
• three-dart-materials — PBR and standard materials
• three-dart-animation — AnimationMixer, keyframe clips
• three-dart-loaders — GLTF/GLB model loading