【问题标题】:ES6 Import inside of Android Webview - not a constructor errorAndroid Webview 内部的 ES6 导入 - 不是构造函数错误
【发布时间】:2020-01-08 01:18:30
【问题描述】:

我在 WebView 中渲染一个 html 网页,它使用 three.js 渲染 3D 模型。到目前为止,所有这些都运行良好。我现在正在尝试添加触摸/拖动控件来移动相机。我找到了一些示例代码来完成这项工作,并且我已经实现了它。以下是相关部分代码:

import * as tc from './TrackballControls.js';
//....
controls = new tc.TrackballControls( camera , renderer.domElement);
controls.rotateSpeed = 1.0;
controls.zoomSpeed = 1.2;
controls.panSpeed = 0.8;

在 Crome 和 Firefox 的 PC 上一切正常,我的模型渲染和拖动确实改变了相机视图。在我的 Android 设备上的 Chrome 和 Firefox 中,通过本地网络加载页面,一切正常。

但是在我的应用程序的 WebView 中,我收到了这个错误:

Uncaught TypeError: tc.TrackballControls is not a constructor

似乎创建 TrackballControls 对象失败了。为什么它在 WebView 内部以这种方式失败,而不是在同一部手机上的 Chrome 中失败?

这是我的html app目录结构:

我已经编辑了 three.module.js 和 TrackballControls.js 以说明它们在同一个目录中,如下所示:

// in index.html js:
import * as THREE from './three.module.js';
import * as tc from './TrackballControls.js';    

// in TrackballControls.js:
import {
  EventDispatcher,
  MOUSE,
  Quaternion,
  Vector2,
  Vector3
} from "./three.module.js";

我可以在 html/javascript 或 Android java 代码中更改什么以使其在 WebView 中正常工作吗?

我在 2 种不同的设备上尝试过,它们的 webview userAgent 字符串是:

"Mozilla/5.0 (Linux; Android 6.0.1; S60 Build/MMB29M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/79.0.3945.93 Mobile Safari/537.36", source: https://appassets.androidplatform.net/assets/www/cpb_3d_model_wgt/index.html (27)

"Mozilla/5.0 (Linux; Android 8.1.0; LM-V405 Build/OPM1.171019.026; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/79.0.3945.93 Mobile Safari/537.36", source: https://appassets.androidplatform.net/assets/www/cpb_3d_model_wgt/index.html (27)

编辑更多信息: 我试图使用以下方法从 Assets 目录中提供我的页面:

final WebViewAssetLoader assetLoader = new WebViewAssetLoader.Builder()
            .addPathHandler("/assets/", new WebViewAssetLoader.AssetsPathHandler(this))
            .addPathHandler("/res/", new WebViewAssetLoader.ResourcesPathHandler(this))
            .build();

    wv.setWebViewClient(new WebViewClient() {
        @Override
        public WebResourceResponse shouldInterceptRequest(WebView view,
                                                          WebResourceRequest request) {
           if (!request.isForMainFrame() && request.getUrl().getPath().endsWith(".js")) {
                Log.d(TAG, " js file request need to set mime/type " + request.getUrl().getPath());
               try {
                   return new WebResourceResponse("application/javascript", null, new BufferedInputStream(view.getContext().getAssets().open("www/cpb_3d_model_wgt/three.module.js")));
               } catch (IOException e) {
                   e.printStackTrace();
               }
            }
            return assetLoader.shouldInterceptRequest(request.getUrl());
        }

        @RequiresApi(api = Build.VERSION_CODES.M)
        @Override
        public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
            super.onReceivedError(view, request, error);
            //Log.d(TAG, "error: " + error.getDescription());
            Log.d(TAG, "error: " + request.getUrl());
        }
    });

    wv.loadUrl("https://appassets.androidplatform.net/assets/www/cpb_3d_model_wgt/index.html");

以这种方式提供我的页面时,我收到了not a constructor 错误。我使用 chrome 远程设备检查器查看了 TrackballControl.js 文件的网络请求,我看到了:

当我的电脑使用 python 网络服务器提供相同的页面时,一切正常(没有错误,所有功能都正常)这些是响应头:

据我所知,响应或标头导致导入问题导致代码失败,因为导入的构造函数没有正确存在。

一旦我注意到响应标头中的这种差异,我就放弃了WebViewAssetLoader,并开始使用 NanoHTTPD 为我的页面提供服务,当它以这种方式提供服务时,一切都按预期工作。

另一个编辑: 现在回顾我的资产加载器/拦截请求代码,我可以看到我已经硬编码了“错误”的 js 文件,以便为每个以 .js 结尾的请求返回很可能是“不是构造函数错误”的原因我的错误,我最初发布问题时应该包含该代码但我忽略了它。

【问题讨论】:

  • 什么版本的Android WebView? (navigator.userAgent)
  • 另外请注意,除非您修改了源代码,否则您需要保留three.js repo 的结构以使用import。这意味着three.module.js 需要在somefolder/build 中,而TrackballControls.js 需要在somefolder/examples/jsm/controls/TrackballControls.js 中,因为在它内部引用three.module.js ../../../build/three.module.js (github.com/mrdoob/three.js/blob/…)
  • 我确实将文件修改为我们资产目录根目录下的 js 文件。我明天会从用户代理发布目录结构和版本
  • @gman 我已经添加了 userAgent 字符串以及有关我的目录结构和 js 文件修改的更多详细信息。
  • 您是否检查了显示 WebView 的应用程序的权限?

标签: javascript android ecmascript-6 webview three.js


【解决方案1】:

TrackballControls.js 不是作为可以导入的模块编写的。相反,它假定THREE 变量是全局可用的,并将其附加到THREE。要解决此问题,您可能需要将其source code 复制并粘贴到您自己的文件中(我们称之为TC.js)并在开头和结尾进行一些更改:

TC.js:

// 1. Import THREE instead of assuming it's globally available
import * as THREE from './three.module.js';

// 2a. Remove "THREE." and make it a stand-alone variable
var TrackballControls = function ( object, domElement ) {

    // ... All 600+ lines of internal content stays the same

};

// 2a. Remove "THREE." at the bottom of the file as well
TrackballControls.prototype = Object.create( THREE.EventDispatcher.prototype );
TrackballControls.prototype.constructor = TrackballControls;

// 3. Export the object to be used in other files
export default TrackballControls;

现在您应该可以在项目中使用自己的TC.js 文件了:

main.js:

import * as THREE from './three.module.js';
import TrackballControls from 'TC.js';

const controls = new TrackballControls(camera , renderer.domElement);

我在下面做了一个例子来演示复制粘贴TrackballControls 仍然可以通过使其成为独立变量来工作。前 600 多行实际上是复制粘贴的,经过我上面提到的修改。场景设置的其余部分在 JS 的末尾:

// In your code, you'd import THREE here, instead of via <script> tag
// import * as THREE from 'three';

const TrackballControls = function ( object, domElement ) {

	if ( domElement === undefined ) console.warn( 'THREE.TrackballControls: The second parameter "domElement" is now mandatory.' );
	if ( domElement === document ) console.error( 'THREE.TrackballControls: "document" should not be used as the target "domElement". Please use "renderer.domElement" instead.' );

	var _this = this;
	var STATE = { NONE: - 1, ROTATE: 0, ZOOM: 1, PAN: 2, TOUCH_ROTATE: 3, TOUCH_ZOOM_PAN: 4 };

	this.object = object;
	this.domElement = domElement;

	// API

	this.enabled = true;

	this.screen = { left: 0, top: 0, width: 0, height: 0 };

	this.rotateSpeed = 1.0;
	this.zoomSpeed = 1.2;
	this.panSpeed = 0.3;

	this.noRotate = false;
	this.noZoom = false;
	this.noPan = false;

	this.staticMoving = false;
	this.dynamicDampingFactor = 0.2;

	this.minDistance = 0;
	this.maxDistance = Infinity;

	this.keys = [ 65 /*A*/, 83 /*S*/, 68 /*D*/ ];

	this.mouseButtons = { LEFT: THREE.MOUSE.ROTATE, MIDDLE: THREE.MOUSE.ZOOM, RIGHT: THREE.MOUSE.PAN };

	// internals

	this.target = new THREE.Vector3();

	var EPS = 0.000001;

	var lastPosition = new THREE.Vector3();
	var lastZoom = 1;

	var _state = STATE.NONE,
		_keyState = STATE.NONE,

		_eye = new THREE.Vector3(),

		_movePrev = new THREE.Vector2(),
		_moveCurr = new THREE.Vector2(),

		_lastAxis = new THREE.Vector3(),
		_lastAngle = 0,

		_zoomStart = new THREE.Vector2(),
		_zoomEnd = new THREE.Vector2(),

		_touchZoomDistanceStart = 0,
		_touchZoomDistanceEnd = 0,

		_panStart = new THREE.Vector2(),
		_panEnd = new THREE.Vector2();

	// for reset

	this.target0 = this.target.clone();
	this.position0 = this.object.position.clone();
	this.up0 = this.object.up.clone();
	this.zoom0 = this.object.zoom;

	// events

	var changeEvent = { type: 'change' };
	var startEvent = { type: 'start' };
	var endEvent = { type: 'end' };


	// methods

	this.handleResize = function () {

		var box = this.domElement.getBoundingClientRect();
		// adjustments come from similar code in the jquery offset() function
		var d = this.domElement.ownerDocument.documentElement;
		this.screen.left = box.left + window.pageXOffset - d.clientLeft;
		this.screen.top = box.top + window.pageYOffset - d.clientTop;
		this.screen.width = box.width;
		this.screen.height = box.height;

	};

	var getMouseOnScreen = ( function () {

		var vector = new THREE.Vector2();

		return function getMouseOnScreen( pageX, pageY ) {

			vector.set(
				( pageX - _this.screen.left ) / _this.screen.width,
				( pageY - _this.screen.top ) / _this.screen.height
			);

			return vector;

		};

	}() );

	var getMouseOnCircle = ( function () {

		var vector = new THREE.Vector2();

		return function getMouseOnCircle( pageX, pageY ) {

			vector.set(
				( ( pageX - _this.screen.width * 0.5 - _this.screen.left ) / ( _this.screen.width * 0.5 ) ),
				( ( _this.screen.height + 2 * ( _this.screen.top - pageY ) ) / _this.screen.width ) // screen.width intentional
			);

			return vector;

		};

	}() );

	this.rotateCamera = ( function () {

		var axis = new THREE.Vector3(),
			quaternion = new THREE.Quaternion(),
			eyeDirection = new THREE.Vector3(),
			objectUpDirection = new THREE.Vector3(),
			objectSidewaysDirection = new THREE.Vector3(),
			moveDirection = new THREE.Vector3(),
			angle;

		return function rotateCamera() {

			moveDirection.set( _moveCurr.x - _movePrev.x, _moveCurr.y - _movePrev.y, 0 );
			angle = moveDirection.length();

			if ( angle ) {

				_eye.copy( _this.object.position ).sub( _this.target );

				eyeDirection.copy( _eye ).normalize();
				objectUpDirection.copy( _this.object.up ).normalize();
				objectSidewaysDirection.crossVectors( objectUpDirection, eyeDirection ).normalize();

				objectUpDirection.setLength( _moveCurr.y - _movePrev.y );
				objectSidewaysDirection.setLength( _moveCurr.x - _movePrev.x );

				moveDirection.copy( objectUpDirection.add( objectSidewaysDirection ) );

				axis.crossVectors( moveDirection, _eye ).normalize();

				angle *= _this.rotateSpeed;
				quaternion.setFromAxisAngle( axis, angle );

				_eye.applyQuaternion( quaternion );
				_this.object.up.applyQuaternion( quaternion );

				_lastAxis.copy( axis );
				_lastAngle = angle;

			} else if ( ! _this.staticMoving && _lastAngle ) {

				_lastAngle *= Math.sqrt( 1.0 - _this.dynamicDampingFactor );
				_eye.copy( _this.object.position ).sub( _this.target );
				quaternion.setFromAxisAngle( _lastAxis, _lastAngle );
				_eye.applyQuaternion( quaternion );
				_this.object.up.applyQuaternion( quaternion );

			}

			_movePrev.copy( _moveCurr );

		};

	}() );


	this.zoomCamera = function () {

		var factor;

		if ( _state === STATE.TOUCH_ZOOM_PAN ) {

			factor = _touchZoomDistanceStart / _touchZoomDistanceEnd;
			_touchZoomDistanceStart = _touchZoomDistanceEnd;

			if ( _this.object.isPerspectiveCamera ) {

				_eye.multiplyScalar( factor );

			} else if ( _this.object.isOrthographicCamera ) {

				_this.object.zoom *= factor;
				_this.object.updateProjectionMatrix();

			} else {

				console.warn( 'THREE.TrackballControls: Unsupported camera type' );

			}

		} else {

			factor = 1.0 + ( _zoomEnd.y - _zoomStart.y ) * _this.zoomSpeed;

			if ( factor !== 1.0 && factor > 0.0 ) {

				if ( _this.object.isPerspectiveCamera ) {

					_eye.multiplyScalar( factor );

				} else if ( _this.object.isOrthographicCamera ) {

					_this.object.zoom /= factor;
					_this.object.updateProjectionMatrix();

				} else {

					console.warn( 'THREE.TrackballControls: Unsupported camera type' );

				}

			}

			if ( _this.staticMoving ) {

				_zoomStart.copy( _zoomEnd );

			} else {

				_zoomStart.y += ( _zoomEnd.y - _zoomStart.y ) * this.dynamicDampingFactor;

			}

		}

	};

	this.panCamera = ( function () {

		var mouseChange = new THREE.Vector2(),
			objectUp = new THREE.Vector3(),
			pan = new THREE.Vector3();

		return function panCamera() {

			mouseChange.copy( _panEnd ).sub( _panStart );

			if ( mouseChange.lengthSq() ) {

				if ( _this.object.isOrthographicCamera ) {

					var scale_x = ( _this.object.right - _this.object.left ) / _this.object.zoom / _this.domElement.clientWidth;
					var scale_y = ( _this.object.top - _this.object.bottom ) / _this.object.zoom / _this.domElement.clientWidth;

					mouseChange.x *= scale_x;
					mouseChange.y *= scale_y;

				}

				mouseChange.multiplyScalar( _eye.length() * _this.panSpeed );

				pan.copy( _eye ).cross( _this.object.up ).setLength( mouseChange.x );
				pan.add( objectUp.copy( _this.object.up ).setLength( mouseChange.y ) );

				_this.object.position.add( pan );
				_this.target.add( pan );

				if ( _this.staticMoving ) {

					_panStart.copy( _panEnd );

				} else {

					_panStart.add( mouseChange.subVectors( _panEnd, _panStart ).multiplyScalar( _this.dynamicDampingFactor ) );

				}

			}

		};

	}() );

	this.checkDistances = function () {

		if ( ! _this.noZoom || ! _this.noPan ) {

			if ( _eye.lengthSq() > _this.maxDistance * _this.maxDistance ) {

				_this.object.position.addVectors( _this.target, _eye.setLength( _this.maxDistance ) );
				_zoomStart.copy( _zoomEnd );

			}

			if ( _eye.lengthSq() < _this.minDistance * _this.minDistance ) {

				_this.object.position.addVectors( _this.target, _eye.setLength( _this.minDistance ) );
				_zoomStart.copy( _zoomEnd );

			}

		}

	};

	this.update = function () {

		_eye.subVectors( _this.object.position, _this.target );

		if ( ! _this.noRotate ) {

			_this.rotateCamera();

		}

		if ( ! _this.noZoom ) {

			_this.zoomCamera();

		}

		if ( ! _this.noPan ) {

			_this.panCamera();

		}

		_this.object.position.addVectors( _this.target, _eye );

		if ( _this.object.isPerspectiveCamera ) {

			_this.checkDistances();

			_this.object.lookAt( _this.target );

			if ( lastPosition.distanceToSquared( _this.object.position ) > EPS ) {

				_this.dispatchEvent( changeEvent );

				lastPosition.copy( _this.object.position );

			}

		} else if ( _this.object.isOrthographicCamera ) {

			_this.object.lookAt( _this.target );

			if ( lastPosition.distanceToSquared( _this.object.position ) > EPS || lastZoom !== _this.object.zoom ) {

				_this.dispatchEvent( changeEvent );

				lastPosition.copy( _this.object.position );
				lastZoom = _this.object.zoom;

			}

		} else {

			console.warn( 'THREE.TrackballControls: Unsupported camera type' );

		}

	};

	this.reset = function () {

		_state = STATE.NONE;
		_keyState = STATE.NONE;

		_this.target.copy( _this.target0 );
		_this.object.position.copy( _this.position0 );
		_this.object.up.copy( _this.up0 );
		_this.object.zoom = _this.zoom0;

		_this.object.updateProjectionMatrix();

		_eye.subVectors( _this.object.position, _this.target );

		_this.object.lookAt( _this.target );

		_this.dispatchEvent( changeEvent );

		lastPosition.copy( _this.object.position );
		lastZoom = _this.object.zoom;

	};

	// listeners

	function keydown( event ) {

		if ( _this.enabled === false ) return;

		window.removeEventListener( 'keydown', keydown );

		if ( _keyState !== STATE.NONE ) {

			return;

		} else if ( event.keyCode === _this.keys[ STATE.ROTATE ] && ! _this.noRotate ) {

			_keyState = STATE.ROTATE;

		} else if ( event.keyCode === _this.keys[ STATE.ZOOM ] && ! _this.noZoom ) {

			_keyState = STATE.ZOOM;

		} else if ( event.keyCode === _this.keys[ STATE.PAN ] && ! _this.noPan ) {

			_keyState = STATE.PAN;

		}

	}

	function keyup() {

		if ( _this.enabled === false ) return;

		_keyState = STATE.NONE;

		window.addEventListener( 'keydown', keydown, false );

	}

	function mousedown( event ) {

		if ( _this.enabled === false ) return;

		event.preventDefault();
		event.stopPropagation();

		if ( _state === STATE.NONE ) {

			switch ( event.button ) {

				case _this.mouseButtons.LEFT:
					_state = STATE.ROTATE;
					break;

				case _this.mouseButtons.MIDDLE:
					_state = STATE.ZOOM;
					break;

				case _this.mouseButtons.RIGHT:
					_state = STATE.PAN;
					break;

				default:
					_state = STATE.NONE;

			}

		}

		var state = ( _keyState !== STATE.NONE ) ? _keyState : _state;

		if ( state === STATE.ROTATE && ! _this.noRotate ) {

			_moveCurr.copy( getMouseOnCircle( event.pageX, event.pageY ) );
			_movePrev.copy( _moveCurr );

		} else if ( state === STATE.ZOOM && ! _this.noZoom ) {

			_zoomStart.copy( getMouseOnScreen( event.pageX, event.pageY ) );
			_zoomEnd.copy( _zoomStart );

		} else if ( state === STATE.PAN && ! _this.noPan ) {

			_panStart.copy( getMouseOnScreen( event.pageX, event.pageY ) );
			_panEnd.copy( _panStart );

		}

		document.addEventListener( 'mousemove', mousemove, false );
		document.addEventListener( 'mouseup', mouseup, false );

		_this.dispatchEvent( startEvent );

	}

	function mousemove( event ) {

		if ( _this.enabled === false ) return;

		event.preventDefault();
		event.stopPropagation();

		var state = ( _keyState !== STATE.NONE ) ? _keyState : _state;

		if ( state === STATE.ROTATE && ! _this.noRotate ) {

			_movePrev.copy( _moveCurr );
			_moveCurr.copy( getMouseOnCircle( event.pageX, event.pageY ) );

		} else if ( state === STATE.ZOOM && ! _this.noZoom ) {

			_zoomEnd.copy( getMouseOnScreen( event.pageX, event.pageY ) );

		} else if ( state === STATE.PAN && ! _this.noPan ) {

			_panEnd.copy( getMouseOnScreen( event.pageX, event.pageY ) );

		}

	}

	function mouseup( event ) {

		if ( _this.enabled === false ) return;

		event.preventDefault();
		event.stopPropagation();

		_state = STATE.NONE;

		document.removeEventListener( 'mousemove', mousemove );
		document.removeEventListener( 'mouseup', mouseup );
		_this.dispatchEvent( endEvent );

	}

	function mousewheel( event ) {

		if ( _this.enabled === false ) return;

		if ( _this.noZoom === true ) return;

		event.preventDefault();
		event.stopPropagation();

		switch ( event.deltaMode ) {

			case 2:
				// Zoom in pages
				_zoomStart.y -= event.deltaY * 0.025;
				break;

			case 1:
				// Zoom in lines
				_zoomStart.y -= event.deltaY * 0.01;
				break;

			default:
				// undefined, 0, assume pixels
				_zoomStart.y -= event.deltaY * 0.00025;
				break;

		}

		_this.dispatchEvent( startEvent );
		_this.dispatchEvent( endEvent );

	}

	function touchstart( event ) {

		if ( _this.enabled === false ) return;

		event.preventDefault();

		switch ( event.touches.length ) {

			case 1:
				_state = STATE.TOUCH_ROTATE;
				_moveCurr.copy( getMouseOnCircle( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY ) );
				_movePrev.copy( _moveCurr );
				break;

			default: // 2 or more
				_state = STATE.TOUCH_ZOOM_PAN;
				var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
				var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;
				_touchZoomDistanceEnd = _touchZoomDistanceStart = Math.sqrt( dx * dx + dy * dy );

				var x = ( event.touches[ 0 ].pageX + event.touches[ 1 ].pageX ) / 2;
				var y = ( event.touches[ 0 ].pageY + event.touches[ 1 ].pageY ) / 2;
				_panStart.copy( getMouseOnScreen( x, y ) );
				_panEnd.copy( _panStart );
				break;

		}

		_this.dispatchEvent( startEvent );

	}

	function touchmove( event ) {

		if ( _this.enabled === false ) return;

		event.preventDefault();
		event.stopPropagation();

		switch ( event.touches.length ) {

			case 1:
				_movePrev.copy( _moveCurr );
				_moveCurr.copy( getMouseOnCircle( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY ) );
				break;

			default: // 2 or more
				var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
				var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;
				_touchZoomDistanceEnd = Math.sqrt( dx * dx + dy * dy );

				var x = ( event.touches[ 0 ].pageX + event.touches[ 1 ].pageX ) / 2;
				var y = ( event.touches[ 0 ].pageY + event.touches[ 1 ].pageY ) / 2;
				_panEnd.copy( getMouseOnScreen( x, y ) );
				break;

		}

	}

	function touchend( event ) {

		if ( _this.enabled === false ) return;

		switch ( event.touches.length ) {

			case 0:
				_state = STATE.NONE;
				break;

			case 1:
				_state = STATE.TOUCH_ROTATE;
				_moveCurr.copy( getMouseOnCircle( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY ) );
				_movePrev.copy( _moveCurr );
				break;

		}

		_this.dispatchEvent( endEvent );

	}

	function contextmenu( event ) {

		if ( _this.enabled === false ) return;

		event.preventDefault();

	}

	this.dispose = function () {

		this.domElement.removeEventListener( 'contextmenu', contextmenu, false );
		this.domElement.removeEventListener( 'mousedown', mousedown, false );
		this.domElement.removeEventListener( 'wheel', mousewheel, false );

		this.domElement.removeEventListener( 'touchstart', touchstart, false );
		this.domElement.removeEventListener( 'touchend', touchend, false );
		this.domElement.removeEventListener( 'touchmove', touchmove, false );

		document.removeEventListener( 'mousemove', mousemove, false );
		document.removeEventListener( 'mouseup', mouseup, false );

		window.removeEventListener( 'keydown', keydown, false );
		window.removeEventListener( 'keyup', keyup, false );

	};

	this.domElement.addEventListener( 'contextmenu', contextmenu, false );
	this.domElement.addEventListener( 'mousedown', mousedown, false );
	this.domElement.addEventListener( 'wheel', mousewheel, false );

	this.domElement.addEventListener( 'touchstart', touchstart, false );
	this.domElement.addEventListener( 'touchend', touchend, false );
	this.domElement.addEventListener( 'touchmove', touchmove, false );

	window.addEventListener( 'keydown', keydown, false );
	window.addEventListener( 'keyup', keyup, false );

	this.handleResize();

	// force an update at start
	this.update();

};

TrackballControls.prototype = Object.create( THREE.EventDispatcher.prototype );
TrackballControls.prototype.constructor = TrackballControls;

//////////////////////////// END OF TRACKBALL SOURCE CODE ////////////////////////////

// Boilerplate Three setup
const renderer = new THREE.WebGLRenderer({canvas: document.querySelector("canvas")});
const camera = new THREE.PerspectiveCamera(70, 1, 1, 1000);
camera.position.z = 20;

const scene = new THREE.Scene();
const geometry = new THREE.TorusBufferGeometry(8, 3, 16, 32);
const material = new THREE.MeshNormalMaterial();
const mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);

// Now we can use the controls as expected
const controls = new TrackballControls(camera , renderer.domElement );
controls.rotateSpeed = 1.0;
controls.zoomSpeed = 1.2;
controls.panSpeed = 0.8;

function resize() {
  var width = renderer.domElement.clientWidth;
  var height = renderer.domElement.clientHeight;
  if (renderer.domElement.width !== width || renderer.domElement.height !== height) {
    renderer.setSize(width, height, false);
    camera.aspect = width / height;
    camera.updateProjectionMatrix();
  }
}

function animate(time) {
  controls.update();
  renderer.render(scene, camera);
  requestAnimationFrame(animate);
}

resize();
requestAnimationFrame(animate);
body { margin: 0; }
canvas { width: 100vw; height: 100vh; display: block; }
<canvas></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/110/three.min.js"></script>

【讨论】:

  • 我最终找到了一种解决问题的方法,方法是使用 NanoHTTPD Web 服务器为我现有的页面提供服务,然后从那里将它们加载到 WebView 中。但是,我确实认为以这种方式重构代码可以帮助解决 Javascript 方面的问题,我感谢您花时间制作示例代码并解释更改。我奖励你赏金。谢谢。
【解决方案2】:

TrackballControls.js 不是 ES6 模块,不会导出 TrackballControls 构造函数。 TrackballControls 附加到 THREEts 可能只是一个空对象,ts.TrackballControls 是未定义的。 改为如下定义controls

controls = new THREE.TrackballControls( camera , renderer.domElement);

我的回答是基于 Github 上的 TrackballControls.js

【讨论】:

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