addressing feedback

src/renderers/WebGLRenderer.js

@@ -2728,7 +2728,7 @@ function WebGLRenderer( parameters ) {
 
 		textures.setTexture2D( texture, 0 );
 
-		_gl.copyTexImage2D( _gl.TEXTURE_2D, level || 0, glFormat, position.x, position.y, width, height, 0 );
+		_gl.copyTexImage2D( _gl.TEXTURE_2D, level, glFormat, position.x, position.y, width, height, 0 );
 
 	};