Flutter增强现实功能插件 ar_flutter_plugin_engine 的使用

概述

ar_flutter_plugin_engine 是一个支持 ARKit（iOS）和 ARCore（Android）的 Flutter 插件，用于创建协作式增强现实应用。该插件基于 arkit_flutter_plugin 和 arcore_flutter_plugin，并在此基础上进行了扩展。

安装与配置

1. 添加依赖

在项目的 pubspec.yaml 文件中添加以下依赖：

dependencies:
  ar_flutter_plugin_engine: ^1.0.0

然后运行以下命令安装依赖：

flutter pub get

2. 导入插件

在 Dart 文件中导入插件：

import 'package:ar_flutter_plugin_engine/ar_flutter_plugin.dart';

3. iOS 权限设置

如果你遇到 iOS 设备上的权限问题（例如相机视图无法显示），可以在 ios/Podfile 中添加以下内容：

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_ios_build_settings(target)
    target.build_configurations.each do |config|
      config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
        '$(inherited)',

        ## dart: PermissionGroup.camera
        'PERMISSION_CAMERA=1',

        ## dart: PermissionGroup.photos
        'PERMISSION_PHOTOS=1',

        ## dart: [PermissionGroup.location, PermissionGroup.locationAlways, PermissionGroup.locationWhenInUse]
        'PERMISSION_LOCATION=1',

        ## dart: PermissionGroup.sensors
        'PERMISSION_SENSORS=1',

        ## dart: PermissionGroup.bluetooth
        'PERMISSION_BLUETOOTH=1',
      ]
    end
  end
end

示例代码

以下是一个简单的示例应用，展示了如何使用 ar_flutter_plugin_engine 插件来创建不同的 AR 场景。

主入口文件 main.dart

import 'package:flutter/material.dart';
import 'examples/debugoptionsexample.dart';
import 'examples/localandwebobjectsexample.dart';
import 'examples/objectsonplanesexample.dart';
import 'examples/objectgesturesexample.dart';
import 'examples/screenshotexample.dart';
import 'examples/cloudanchorexample.dart';
import 'examples/externalmodelmanagementexample.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  [@override](/user/override)
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _platformVersion = 'Unknown';
  static const String _title = 'AR Plugin Demo';

  [@override](/user/override)
  void initState() {
    super.initState();
    initPlatformState();
  }

  Future<void> initPlatformState() async {
    String platformVersion;
    try {
      platformVersion = await ArFlutterPlugin.platformVersion;
    } on PlatformException {
      platformVersion = 'Failed to get platform version.';
    }

    if (!mounted) return;

    setState(() {
      _platformVersion = platformVersion;
    });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text(_title),
        ),
        body: Column(children: [
          Text('Running on: $_platformVersion\n'),
          Expanded(
            child: ExampleList(),
          ),
        ]),
      ),
    );
  }
}

class ExampleList extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    final examples = [
      Example(
        'Debug Options',
        'Visualize feature points, planes and world coordinate system',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => DebugOptionsWidget())),
      ),
      Example(
        'Local & Online Objects',
        'Place 3D objects from Flutter assets and the web into the scene',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => LocalAndWebObjectsWidget())),
      ),
      Example(
        'Anchors & Objects on Planes',
        'Place 3D objects on detected planes using anchors',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => ObjectsOnPlanesWidget())),
      ),
      Example(
        'Object Transformation Gestures',
        'Rotate and Pan Objects',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => ObjectGesturesWidget())),
      ),
      Example(
        'Screenshots',
        'Place 3D objects on planes and take screenshots',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => ScreenshotWidget())),
      ),
      Example(
        'Cloud Anchors',
        'Place and retrieve 3D objects using the Google Cloud Anchor API',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => CloudAnchorWidget())),
      ),
      Example(
        'External Model Management',
        'Similar to Cloud Anchors example, but uses external database to choose from available 3D models',
        () => Navigator.push(context, MaterialPageRoute(builder: (context) => ExternalModelManagementWidget())),
      ),
    ];
    return ListView(
      children: examples.map((example) => ExampleCard(example: example)).toList(),
    );
  }
}

class ExampleCard extends StatelessWidget {
  ExampleCard({Key? key, required this.example}) : super(key: key);
  final Example example;

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Card(
      child: InkWell(
        splashColor: Colors.blue.withAlpha(30),
        onTap: () {
          example.onTap();
        },
        child: ListTile(
          title: Text(example.name),
          subtitle: Text(example.description),
        ),
      ),
    );
  }
}

class Example {
  const Example(this.name, this.description, this.onTap);
  final String name;
  final String description;
  final Function onTap;
}

示例场景

1. Debug Options

这是一个简单的 AR 场景，包含切换世界原点、特征点和平面可视化的选项。

// debugoptionsexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class DebugOptionsWidget extends StatefulWidget {
  [@override](/user/override)
  _DebugOptionsWidgetState createState() => _DebugOptionsWidgetState();
}

class _DebugOptionsWidgetState extends State<DebugOptionsWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Debug Options')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}

2. Local & Online Objects

在这个场景中，用户可以放置来自 Flutter 资源或互联网的 GLTF/GLB 对象，并调整其位置、旋转和缩放。

// localandwebobjectsexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class LocalAndWebObjectsWidget extends StatefulWidget {
  [@override](/user/override)
  _LocalAndWebObjectsWidgetState createState() => _LocalAndWebObjectsWidgetState();
}

class _LocalAndWebObjectsWidgetState extends State<LocalAndWebObjectsWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Local & Online Objects')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}

3. Objects & Anchors on Planes

在这个场景中，用户可以通过点击检测到的平面来创建带有 3D 模型的锚点。

// objectsonplanesexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class ObjectsOnPlanesWidget extends StatefulWidget {
  [@override](/user/override)
  _ObjectsOnPlanesWidgetState createState() => _ObjectsOnPlanesWidgetState();
}

class _ObjectsOnPlanesWidgetState extends State<ObjectsOnPlanesWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Objects & Anchors on Planes')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}

4. Object Transformation Gestures

这个场景允许用户通过手势旋转和平移已放置的对象。

// objectgesturesexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class ObjectGesturesWidget extends StatefulWidget {
  [@override](/user/override)
  _ObjectGesturesWidgetState createState() => _ObjectGesturesWidgetState();
}

class _ObjectGesturesWidgetState extends State<ObjectGesturesWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Object Transformation Gestures')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}

5. Screenshots

这个场景允许用户拍摄 AR 场景的截图。

// screenshotexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class ScreenshotWidget extends StatefulWidget {
  [@override](/user/override)
  _ScreenshotWidgetState createState() => _ScreenshotWidgetState();
}

class _ScreenshotWidgetState extends State<ScreenshotWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Screenshots')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}

6. Cloud Anchors

这个场景允许用户上传和下载对象及其锚点，从而创建可共享的交互式 AR 体验。

// cloudanchorexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class CloudAnchorWidget extends StatefulWidget {
  [@override](/user/override)
  _CloudAnchorWidgetState createState() => _CloudAnchorWidgetState();
}

class _CloudAnchorWidgetState extends State<CloudAnchorWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Cloud Anchors')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}

7. External Model Management

这个场景类似于云锚点示例，但使用外部数据库（Firestore）管理可用的模型。

// externalmodelmanagementexample.dart
import 'package:flutter/material.dart';
import 'package:ar_flutter_plugin/ar_flutter_plugin.dart';

class ExternalModelManagementWidget extends StatefulWidget {
  [@override](/user/override)
  _ExternalModelManagementWidgetState createState() => _ExternalModelManagementWidgetState();
}

class _ExternalModelManagementWidgetState extends State<ExternalModelManagementWidget> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('External Model Management')),
      body: ARView(
        // 配置 AR 视图
      ),
    );
  }
}