three.js/examples/js/interactive/HTMLMesh.js

( function () {

	class HTMLMesh extends THREE.Mesh {

		constructor( dom ) {

			const texture = new HTMLTexture( dom );
			const geometry = new THREE.PlaneGeometry( texture.image.width * 0.001, texture.image.height * 0.001 );
			const material = new THREE.MeshBasicMaterial( {
				map: texture,
				toneMapped: false
			} );
			super( geometry, material );

			function onEvent( event ) {

				material.map.dispatchEvent( event );

			}

			this.addEventListener( 'mousedown', onEvent );
			this.addEventListener( 'mousemove', onEvent );
			this.addEventListener( 'mouseup', onEvent );
			this.addEventListener( 'click', onEvent );

		}

	}

	class HTMLTexture extends THREE.CanvasTexture {

		constructor( dom ) {

			super( html2canvas( dom ) );
			this.dom = dom;
			this.anisotropy = 16;
			this.encoding = THREE.sRGBEncoding;
			this.minFilter = THREE.LinearFilter;
			this.magFilter = THREE.LinearFilter;

		}

		dispatchEvent( event ) {

			htmlevent( this.dom, event.type, event.data.x, event.data.y );
			this.update();

		}

		update() {

			this.image = html2canvas( this.dom );
			this.needsUpdate = true;

		}

	} //


	function html2canvas( element ) {

		var range = document.createRange();

		function Clipper( context ) {

			var clips = [];
			var isClipping = false;

			function doClip() {

				if ( isClipping ) {

					isClipping = false;
					context.restore();

				}

				if ( clips.length === 0 ) return;
				var minX = - Infinity,
					minY = - Infinity;
				var maxX = Infinity,
					maxY = Infinity;

				for ( var i = 0; i < clips.length; i ++ ) {

					var clip = clips[ i ];
					minX = Math.max( minX, clip.x );
					minY = Math.max( minY, clip.y );
					maxX = Math.min( maxX, clip.x + clip.width );
					maxY = Math.min( maxY, clip.y + clip.height );

				}

				context.save();
				context.beginPath();
				context.rect( minX, minY, maxX - minX, maxY - minY );
				context.clip();
				isClipping = true;

			}

			return {
				add: function ( clip ) {

					clips.push( clip );
					doClip();

				},
				remove: function () {

					clips.pop();
					doClip();

				}
			};

		}

		function drawText( style, x, y, string ) {

			if ( string !== '' ) {

				if ( style.textTransform === 'uppercase' ) {

					string = string.toUpperCase();

				}

				context.font = style.fontSize + ' ' + style.fontFamily;
				context.textBaseline = 'top';
				context.fillStyle = style.color;
				context.fillText( string, x, y );

			}

		}

		function drawBorder( style, which, x, y, width, height ) {

			var borderWidth = style[ which + 'Width' ];
			var borderStyle = style[ which + 'Style' ];
			var borderColor = style[ which + 'Color' ];

			if ( borderWidth !== '0px' && borderStyle !== 'none' && borderColor !== 'transparent' && borderColor !== 'rgba(0, 0, 0, 0)' ) {

				context.strokeStyle = borderColor;
				context.beginPath();
				context.moveTo( x, y );
				context.lineTo( x + width, y + height );
				context.stroke();

			}

		}

		function drawElement( element, style ) {

			var x = 0,
				y = 0,
				width = 0,
				height = 0;

			if ( element.nodeType === 3 ) {

				// text
				range.selectNode( element );
				var rect = range.getBoundingClientRect();
				x = rect.left - offset.left - 0.5;
				y = rect.top - offset.top - 0.5;
				width = rect.width;
				height = rect.height;
				drawText( style, x, y, element.nodeValue.trim() );

			} else {

				if ( element.style.display === 'none' ) return;
				var rect = element.getBoundingClientRect();
				x = rect.left - offset.left - 0.5;
				y = rect.top - offset.top - 0.5;
				width = rect.width;
				height = rect.height;
				style = window.getComputedStyle( element );
				var backgroundColor = style.backgroundColor;

				if ( backgroundColor !== 'transparent' && backgroundColor !== 'rgba(0, 0, 0, 0)' ) {

					context.fillStyle = backgroundColor;
					context.fillRect( x, y, width, height );

				}

				drawBorder( style, 'borderTop', x, y, width, 0 );
				drawBorder( style, 'borderLeft', x, y, 0, height );
				drawBorder( style, 'borderBottom', x, y + height, width, 0 );
				drawBorder( style, 'borderRight', x + width, y, 0, height );

				if ( element.type === 'color' || element.type === 'text' ) {

					clipper.add( {
						x: x,
						y: y,
						width: width,
						height: height
					} );
					drawText( style, x + parseInt( style.paddingLeft ), y + parseInt( style.paddingTop ), element.value );
					clipper.remove();

				}

			}
			/*
    // debug
    context.strokeStyle = '#' + Math.random().toString( 16 ).slice( - 3 );
    context.strokeRect( x - 0.5, y - 0.5, width + 1, height + 1 );
    */


			var isClipping = style.overflow === 'auto' || style.overflow === 'hidden';
			if ( isClipping ) clipper.add( {
				x: x,
				y: y,
				width: width,
				height: height
			} );

			for ( var i = 0; i < element.childNodes.length; i ++ ) {

				drawElement( element.childNodes[ i ], style );

			}

			if ( isClipping ) clipper.remove();

		}

		var offset = element.getBoundingClientRect();
		var canvas = document.createElement( 'canvas' );
		canvas.width = offset.width;
		canvas.height = offset.height;
		var context = canvas.getContext( '2d'
			/*, { alpha: false }*/
		);
		var clipper = new Clipper( context ); // console.time( 'drawElement' );

		drawElement( element ); // console.timeEnd( 'drawElement' );

		return canvas;

	}

	function htmlevent( element, event, x, y ) {

		const mouseEventInit = {
			clientX: x * element.offsetWidth + element.offsetLeft,
			clientY: y * element.offsetHeight + element.offsetTop,
			view: element.ownerDocument.defaultView
		};
		window.dispatchEvent( new MouseEvent( event, mouseEventInit ) );
		const rect = element.getBoundingClientRect();
		x = x * rect.width + rect.left;
		y = y * rect.height + rect.top;

		function traverse( element ) {

			if ( element.nodeType !== 3 ) {

				const rect = element.getBoundingClientRect();

				if ( x > rect.left && x < rect.right && y > rect.top && y < rect.bottom ) {

					element.dispatchEvent( new MouseEvent( event, mouseEventInit ) );

				}

				for ( var i = 0; i < element.childNodes.length; i ++ ) {

					traverse( element.childNodes[ i ] );

				}

			}

		}

		traverse( element );

	}

	THREE.HTMLMesh = HTMLMesh;

} )();