diff --git a/simplepbr/__init__.py b/simplepbr/__init__.py
index d09b1d8..302bfc1 100644
--- a/simplepbr/__init__.py
+++ b/simplepbr/__init__.py
@@ -372,6 +372,9 @@ def _update(self, task: p3d.PythonTask) -> int:
         if recompile:
             self._recompile_pbr()
 
+        # Copy window background color so ShowBase.set_background_color() works
+        self._filtermgr.buffers[0].set_clear_color(self.window.get_clear_color())
+
         return task.DS_cont