Merge pull request #15825 from OndrejSpanel/prMirroredShadow

Fix: wrong face cull for shadows of freshly inserted mirrored objects.

src/renderers/WebGLRenderer.js

@@ -706,7 +706,7 @@ function WebGLRenderer( parameters ) {
 
 	this.renderBufferDirect = function ( camera, fog, geometry, material, object, group ) {
 
-		var frontFaceCW = ( object.isMesh && object.normalMatrix.determinant() < 0 );
+		var frontFaceCW = ( object.isMesh && object.matrixWorld.determinant() < 0 );
 
 		state.setMaterial( material, frontFaceCW );