diff --git a/examples/jsm/exporters/GLTFExporter.js b/examples/jsm/exporters/GLTFExporter.js
index 8ec912b4f7269f..1c2e67ef4f236a 100644
--- a/examples/jsm/exporters/GLTFExporter.js
+++ b/examples/jsm/exporters/GLTFExporter.js
@@ -1852,12 +1852,12 @@ class GLTFWriter {
 				! ( array instanceof Uint8Array ) ) {
 
 				console.warn( 'GLTFExporter: Attribute "skinIndex" converted to type UNSIGNED_SHORT.' );
-				modifiedAttribute = new BufferAttribute( new Uint16Array( array ), attribute.itemSize, attribute.normalized );
+				modifiedAttribute = GLTFExporter.Utils.toTypedBufferAttribute( attribute, Uint16Array );
 
 			} else if ( ( array instanceof Uint32Array || array instanceof Int32Array ) && ! attributeName.startsWith( '_' ) ) {
 
 				console.warn( `GLTFExporter: Attribute "${ attributeName }" converted to type FLOAT.` );
-				modifiedAttribute = GLTFExporter.Utils.toFloat32BufferAttribute( attribute );
+				modifiedAttribute = GLTFExporter.Utils.toTypedBufferAttribute( attribute, Float32Array );
 
 			}
 
@@ -3538,9 +3538,9 @@ GLTFExporter.Utils = {
 
 	},
 
-	toFloat32BufferAttribute: function ( srcAttribute ) {
+	toTypedBufferAttribute: function ( srcAttribute, TypedArray ) {
 
-		const dstAttribute = new BufferAttribute( new Float32Array( srcAttribute.count * srcAttribute.itemSize ), srcAttribute.itemSize, false );
+		const dstAttribute = new BufferAttribute( new TypedArray( srcAttribute.count * srcAttribute.itemSize ), srcAttribute.itemSize, false );
 
 		if ( ! srcAttribute.normalized && ! srcAttribute.isInterleavedBufferAttribute ) {
 
diff --git a/examples/jsm/loaders/VTKLoader.js b/examples/jsm/loaders/VTKLoader.js
index af74d3f7da3eeb..d7f249e0d56926 100644
--- a/examples/jsm/loaders/VTKLoader.js
+++ b/examples/jsm/loaders/VTKLoader.js
@@ -112,8 +112,20 @@ class VTKLoader extends Loader {
 			// pattern for detecting the end of a number sequence
 			const patWord = /^[^\d.\s-]+/;
 
-			// pattern for reading vertices, 3 floats or integers
-			const pat3Floats = /(\-?\d+\.?[\d\-\+e]*)\s+(\-?\d+\.?[\d\-\+e]*)\s+(\-?\d+\.?[\d\-\+e]*)/g;
+			function parseFloats( line ) {
+
+				const result = [];
+				const parts = line.split( /\s+/ );
+
+				for ( let i = 0; i < parts.length; i ++ ) {
+
+					if ( parts[ i ] !== '' ) result.push( parseFloat( parts[ i ] ) );
+
+				}
+
+				return result;
+
+			}
 
 			// pattern for connectivity, an integer followed by any number of ints
 			// the first integer is the number of polygon nodes
@@ -165,14 +177,15 @@ class VTKLoader extends Loader {
 				} else if ( inPointsSection ) {
 
 					// get the vertices
-					while ( ( result = pat3Floats.exec( line ) ) !== null ) {
+					if ( patWord.exec( line ) === null ) {
 
-						if ( patWord.exec( line ) !== null ) break;
+						const values = parseFloats( line );
 
-						const x = parseFloat( result[ 1 ] );
-						const y = parseFloat( result[ 2 ] );
-						const z = parseFloat( result[ 3 ] );
-						positions.push( x, y, z );
+						for ( let k = 0; k + 2 < values.length; k += 3 ) {
+
+							positions.push( values[ k ], values[ k + 1 ], values[ k + 2 ] );
+
+						}
 
 					}
 
@@ -243,17 +256,16 @@ class VTKLoader extends Loader {
 
 						// Get the colors
 
-						while ( ( result = pat3Floats.exec( line ) ) !== null ) {
+						if ( patWord.exec( line ) === null ) {
 
-							if ( patWord.exec( line ) !== null ) break;
+							const values = parseFloats( line );
 
-							const r = parseFloat( result[ 1 ] );
-							const g = parseFloat( result[ 2 ] );
-							const b = parseFloat( result[ 3 ] );
+							for ( let k = 0; k + 2 < values.length; k += 3 ) {
 
-							color.setRGB( r, g, b, SRGBColorSpace );
+								color.setRGB( values[ k ], values[ k + 1 ], values[ k + 2 ], SRGBColorSpace );
+								colors.push( color.r, color.g, color.b );
 
-							colors.push( color.r, color.g, color.b );
+							}
 
 						}
 
@@ -261,14 +273,15 @@ class VTKLoader extends Loader {
 
 						// Get the normal vectors
 
-						while ( ( result = pat3Floats.exec( line ) ) !== null ) {
+						if ( patWord.exec( line ) === null ) {
 
-							if ( patWord.exec( line ) !== null ) break;
+							const values = parseFloats( line );
 
-							const nx = parseFloat( result[ 1 ] );
-							const ny = parseFloat( result[ 2 ] );
-							const nz = parseFloat( result[ 3 ] );
-							normals.push( nx, ny, nz );
+							for ( let k = 0; k + 2 < values.length; k += 3 ) {
+
+								normals.push( values[ k ], values[ k + 1 ], values[ k + 2 ] );
+
+							}
 
 						}
 
@@ -400,7 +413,7 @@ class VTKLoader extends Loader {
 				let index = start;
 				let c = buffer[ index ];
 				const s = [];
-				while ( c !== 10 ) {
+				while ( c !== 10 && index < buffer.length ) {
 
 					s.push( String.fromCharCode( c ) );
 					index ++;
diff --git a/src/renderers/WebGLRenderer.js b/src/renderers/WebGLRenderer.js
index 760eaeec1889b0..ea16241325b482 100644
--- a/src/renderers/WebGLRenderer.js
+++ b/src/renderers/WebGLRenderer.js
@@ -2988,6 +2988,10 @@ class WebGLRenderer {
 					const textureFormat = texture.format;
 					const textureType = texture.type;
 
+					// when using MRT, select the correct color buffer for the subsequent read command
+
+					if ( renderTarget.textures.length > 1 ) _gl.readBuffer( _gl.COLOR_ATTACHMENT0 + textureIndex );
+
 					if ( ! capabilities.textureFormatReadable( textureFormat ) ) {
 
 						error( 'WebGLRenderer.readRenderTargetPixels: renderTarget is not in RGBA or implementation defined format.' );
@@ -3006,10 +3010,6 @@ class WebGLRenderer {
 
 					if ( ( x >= 0 && x <= ( renderTarget.width - width ) ) && ( y >= 0 && y <= ( renderTarget.height - height ) ) ) {
 
-						// when using MRT, select the correct color buffer for the subsequent read command
-
-						if ( renderTarget.textures.length > 1 ) _gl.readBuffer( _gl.COLOR_ATTACHMENT0 + textureIndex );
-
 						_gl.readPixels( x, y, width, height, utils.convert( textureFormat ), utils.convert( textureType ), buffer );
 
 					}
@@ -3070,6 +3070,11 @@ class WebGLRenderer {
 					const textureFormat = texture.format;
 					const textureType = texture.type;
 
+					// when using MRT, select the correct color buffer for the subsequent read command
+
+					if ( renderTarget.textures.length > 1 ) _gl.readBuffer( _gl.COLOR_ATTACHMENT0 + textureIndex );
+
+
 					if ( ! capabilities.textureFormatReadable( textureFormat ) ) {
 
 						throw new Error( 'THREE.WebGLRenderer.readRenderTargetPixelsAsync: renderTarget is not in RGBA or implementation defined format.' );
@@ -3086,10 +3091,6 @@ class WebGLRenderer {
 					_gl.bindBuffer( _gl.PIXEL_PACK_BUFFER, glBuffer );
 					_gl.bufferData( _gl.PIXEL_PACK_BUFFER, buffer.byteLength, _gl.STREAM_READ );
 
-					// when using MRT, select the correct color buffer for the subsequent read command
-
-					if ( renderTarget.textures.length > 1 ) _gl.readBuffer( _gl.COLOR_ATTACHMENT0 + textureIndex );
-
 					_gl.readPixels( x, y, width, height, utils.convert( textureFormat ), utils.convert( textureType ), 0 );
 
 					// reset the frame buffer to the currently set buffer before waiting