diff --git a/src/gl/renderer/gl_scene.cpp b/src/gl/renderer/gl_scene.cpp
index b5f2c7b929..f19bf10189 100644
--- a/src/gl/renderer/gl_scene.cpp
+++ b/src/gl/renderer/gl_scene.cpp
@@ -152,7 +152,8 @@ sector_t * FGLRenderer::RenderViewpoint (FRenderViewpoint &mainvp, AActor * came
 {
 	R_SetupFrame (mainvp, r_viewwindow, camera);
 
-	UpdateShadowMap();
+	if (mainview && toscreen)
+		UpdateShadowMap();
 
     // Render (potentially) multiple views for stereo 3d
 	// Fixme. The view offsetting should be done with a static table and not require setup of the entire render state for the mode.