Merge pull request #18973 from Mugen87/dev41

Reflector: Fix rendering bug when using Scene.background.

examples/js/objects/Reflector.js

@@ -162,6 +162,9 @@ THREE.Reflector = function ( geometry, options ) {
 		renderer.shadowMap.autoUpdate = false; // Avoid re-computing shadows
 
 		renderer.setRenderTarget( renderTarget );
+
+		renderer.state.buffers.depth.setMask( true ); // make sure the depth buffer is writable so it can be properly cleared, see #18897
+
 		if ( renderer.autoClear === false ) renderer.clear();
 		renderer.render( scene, virtualCamera );
 

examples/jsm/objects/Reflector.js

@@ -179,6 +179,9 @@ var Reflector = function ( geometry, options ) {
 		renderer.shadowMap.autoUpdate = false; // Avoid re-computing shadows
 
 		renderer.setRenderTarget( renderTarget );
+
+		renderer.state.buffers.depth.setMask( true ); // make sure the depth buffer is writable so it can be properly cleared, see #18897
+
 		if ( renderer.autoClear === false ) renderer.clear();
 		renderer.render( scene, virtualCamera );