Flutter三维渲染插件three_js_core的使用

在Flutter中使用three_js_core插件进行三维渲染，可以结合Dart和Three.js的功能来实现。以下是一个简单的示例代码，展示如何在Flutter应用中集成和使用three_js_core插件进行基本的三维渲染。

首先，确保你已经在pubspec.yaml文件中添加了three_js_core依赖：

dependencies:
  flutter:
    sdk: flutter
  three_js_core: ^最新版本号  # 请替换为实际的最新版本号

然后，运行flutter pub get来安装依赖。

接下来是示例代码，展示如何在Flutter中使用three_js_core：

import 'package:flutter/material.dart';
import 'package:three_js_core/three_js_core.dart' as THREE;
import 'dart:html' as html;

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Three.js Core in Flutter'),
        ),
        body: ThreeJSView(),
      ),
    );
  }
}

class ThreeJSView extends StatefulWidget {
  @override
  _ThreeJSViewState createState() => _ThreeJSViewState();
}

class _ThreeJSViewState extends State<ThreeJSView> {
  html.CanvasElement? canvasElement;
  THREE.Scene? scene;
  THREE.Camera? camera;
  THREE.Renderer? renderer;
  THREE.CubeGeometry? cubeGeometry;
  THREE.MeshBasicMaterial? cubeMaterial;
  THREE.Mesh? cube;

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

  void initThreeJS() {
    // Create canvas element
    canvasElement = html.document.createElement('canvas') as html.CanvasElement;
    html.document.body!.append(canvasElement!);

    // Set up scene
    scene = THREE.Scene()!;

    // Set up camera
    camera = THREE.PerspectiveCamera(
      75,
      window.innerWidth.toDouble() / window.innerHeight.toDouble(),
      0.1,
      1000,
    )!;
    camera!.position.z = 5.0;

    // Set up renderer
    renderer = THREE.WebGLRenderer({
      'canvas': canvasElement!,
    })!;
    renderer!.setSize(window.innerWidth, window.innerHeight);

    // Create cube geometry and material
    cubeGeometry = THREE.BoxGeometry(1.0, 1.0, 1.0)!;
    cubeMaterial = THREE.MeshBasicMaterial({
      'color': THREE.Color(0x00ff00),
      'wireframe': true,
    })!;

    // Create cube mesh and add to scene
    cube = THREE.Mesh(cubeGeometry!, cubeMaterial!)!;
    scene!.add(cube!);

    // Animate
    animate();
  }

  void animate() {
    requestAnimationFrame(animate);

    // Rotate cube
    cube!.rotation.x += 0.01;
    cube!.rotation.y += 0.01;

    // Render scene and camera
    renderer!.render(scene!, camera!);
  }

  @override
  Widget build(BuildContext context) {
    // Use a Container to hold the canvas element
    return Container(
      child: html.HtmlElementView.fromType(
        'canvas',
        createContext: () => canvasElement!,
      ),
    );
  }

  @override
  void dispose() {
    // Clean up resources when the widget is disposed
    renderer?.dispose();
    super.dispose();
  }
}

注意：

1. 由于three_js_core是一个直接封装Three.js的Dart库，所以它的API与Three.js非常相似。在上面的代码中，我们通过html.document.createElement('canvas')创建了一个HTML canvas元素，并将其添加到文档中。
2. 使用了html.HtmlElementView.fromType来将canvas元素嵌入到Flutter的Widget树中。
3. 初始化Three.js的场景、相机和渲染器，并创建一个简单的旋转立方体。
4. 使用requestAnimationFrame进行动画渲染。

此代码示例应能帮助你在Flutter应用中集成和使用three_js_core插件进行三维渲染。根据你的具体需求，你可以进一步扩展和修改这个示例。