diff --git a/src/math/Matrix4.js b/src/math/Matrix4.js
index d0ad3d41c49830..471f9295278253 100644
--- a/src/math/Matrix4.js
+++ b/src/math/Matrix4.js
@@ -234,6 +234,16 @@ class Matrix4 {
 	 */
 	extractBasis( xAxis, yAxis, zAxis ) {
 
+		if ( this.determinant() === 0 ) {
+
+			xAxis.set( 1, 0, 0 );
+			yAxis.set( 0, 1, 0 );
+			zAxis.set( 0, 0, 1 );
+
+			return this;
+
+		}
+
 		xAxis.setFromMatrixColumn( this, 0 );
 		yAxis.setFromMatrixColumn( this, 1 );
 		zAxis.setFromMatrixColumn( this, 2 );
@@ -274,6 +284,12 @@ class Matrix4 {
 	 */
 	extractRotation( m ) {
 
+		if ( m.determinant() === 0 ) {
+
+			return this.identity();
+
+		}
+
 		const te = this.elements;
 		const me = m.elements;
 
@@ -1026,6 +1042,19 @@ class Matrix4 {
 
 		const te = this.elements;
 
+		position.x = te[ 12 ];
+		position.y = te[ 13 ];
+		position.z = te[ 14 ];
+
+		if ( this.determinant() === 0 ) {
+
+			scale.set( 1, 1, 1 );
+			quaternion.identity();
+
+			return this;
+
+		}
+
 		let sx = _v1.set( te[ 0 ], te[ 1 ], te[ 2 ] ).length();
 		const sy = _v1.set( te[ 4 ], te[ 5 ], te[ 6 ] ).length();
 		const sz = _v1.set( te[ 8 ], te[ 9 ], te[ 10 ] ).length();
@@ -1034,10 +1063,6 @@ class Matrix4 {
 		const det = this.determinant();
 		if ( det < 0 ) sx = - sx;
 
-		position.x = te[ 12 ];
-		position.y = te[ 13 ];
-		position.z = te[ 14 ];
-
 		// scale the rotation part
 		_m1.copy( this );
 
diff --git a/src/renderers/webgl-fallback/WebGLBackend.js b/src/renderers/webgl-fallback/WebGLBackend.js
index 167ef97af0cb0f..7b420c1eda1b80 100644
--- a/src/renderers/webgl-fallback/WebGLBackend.js
+++ b/src/renderers/webgl-fallback/WebGLBackend.js
@@ -815,7 +815,7 @@ class WebGLBackend extends Backend {
 		if ( this.discard === false ) {
 
 			// required here to handle async behaviour of render.compute()
-			gl.enable( gl.RASTERIZER_DISCARD );
+			state.enable( gl.RASTERIZER_DISCARD );
 			this.discard = true;
 
 		}
@@ -901,11 +901,11 @@ class WebGLBackend extends Backend {
 	 */
 	finishCompute( computeGroup ) {
 
-		const gl = this.gl;
+		const { state, gl } = this;
 
 		this.discard = false;
 
-		gl.disable( gl.RASTERIZER_DISCARD );
+		state.disable( gl.RASTERIZER_DISCARD );
 
 		this.prepareTimestampBuffer( TimestampQuery.COMPUTE, this.getTimestampUID( computeGroup ) );
 
diff --git a/src/renderers/webgl-fallback/utils/WebGLState.js b/src/renderers/webgl-fallback/utils/WebGLState.js
index 556a6ef763c00d..d9e5d5bf820c8c 100644
--- a/src/renderers/webgl-fallback/utils/WebGLState.js
+++ b/src/renderers/webgl-fallback/utils/WebGLState.js
@@ -625,11 +625,11 @@ class WebGLState {
 
 		if ( boolean ) {
 
-			gl.enable( gl.SCISSOR_TEST );
+			this.enable( gl.SCISSOR_TEST );
 
 		} else {
 
-			gl.disable( gl.SCISSOR_TEST );
+			this.disable( gl.SCISSOR_TEST );
 
 		}
 
diff --git a/src/renderers/webgl-fallback/utils/WebGLTextureUtils.js b/src/renderers/webgl-fallback/utils/WebGLTextureUtils.js
index f6da1850f5ea10..41846e7ec63005 100644
--- a/src/renderers/webgl-fallback/utils/WebGLTextureUtils.js
+++ b/src/renderers/webgl-fallback/utils/WebGLTextureUtils.js
@@ -488,7 +488,7 @@ class WebGLTextureUtils {
 		backend.state.unbindTexture();
 		// debug
 		// const framebuffer = gl.createFramebuffer();
-		// gl.bindFramebuffer( gl.FRAMEBUFFER, framebuffer );
+		// backend.state.bindFramebuffer( gl.FRAMEBUFFER, framebuffer );
 		// gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, glTextureType, textureGPU, 0 );
 
 		// const readout = new Float32Array( width * height * 4 );
@@ -497,7 +497,7 @@ class WebGLTextureUtils {
 		// const altType = gl.getParameter( gl.IMPLEMENTATION_COLOR_READ_TYPE );
 
 		// gl.readPixels( 0, 0, width, height, altFormat, altType, readout );
-		// gl.bindFramebuffer( gl.FRAMEBUFFER, null );
+		// backend.state.bindFramebuffer( gl.FRAMEBUFFER, null );
 		// log( readout );
 
 	}
@@ -1183,7 +1183,7 @@ class WebGLTextureUtils {
 
 		const fb = gl.createFramebuffer();
 
-		gl.bindFramebuffer( gl.READ_FRAMEBUFFER, fb );
+		backend.state.bindFramebuffer( gl.READ_FRAMEBUFFER, fb );
 
 		const target = texture.isCubeTexture ? gl.TEXTURE_CUBE_MAP_POSITIVE_X + faceIndex : gl.TEXTURE_2D;
 
@@ -1210,6 +1210,8 @@ class WebGLTextureUtils {
 		gl.getBufferSubData( gl.PIXEL_PACK_BUFFER, 0, dstBuffer );
 		gl.bindBuffer( gl.PIXEL_PACK_BUFFER, null );
 
+		backend.state.bindFramebuffer( gl.READ_FRAMEBUFFER, null );
+
 		gl.deleteFramebuffer( fb );
 
 		return dstBuffer;