Optimize which surfaces are passed to lightmapper

src/rendering/hwrenderer/doom_levelmesh.cpp

@@ -204,6 +204,7 @@ void DoomLevelMesh::PropagateLight(const LevelMeshLight* light, std::set<LevelMe
 
 		// TODO skip any surface which isn't physically connected to the sector group in which the light resides
 		//if (light-> == surface.sectorGroup)
+		if (IsInFrontOfPlane(surface.plane, light->RelativeOrigin))
 		{
 			if (surface.portalIndex >= 0)
 			{

src/rendering/hwrenderer/scene/hw_bsp.cpp

@@ -869,7 +869,7 @@ void UpdateLightmaps(DFrameBuffer* screen, FRenderState& RenderState)
 	{
 		for (auto& e : level.levelMesh->Surfaces)
 		{
-			if (e.needsUpdate)
+			if (e.needsUpdate && !e.bSky)
 			{
 				list.Push(&e);