--- a/Indoor.cpp	Wed Jun 05 21:00:45 2013 +0600
+++ b/Indoor.cpp	Fri Jun 07 22:24:11 2013 +0600
@@ -768,7 +768,7 @@
             v7 = sub_423B5D(v1);
             if ( v7 )
             {
-              if ( sub_424829(v7, &stru_F8A590, pBLVRenderParams->field_7C, v1) )
+              if ( isVisibleRoom(v7, &stru_F8A590, pBLVRenderParams->field_7C, v1) )
               {
                 if ( v2->uPolygonType == 1 )
                 {
@@ -1384,7 +1384,7 @@
 //          face_min_screenspace_x <= p->uViewportZ &&
           face_max_screenspace_y >= p->uViewportY &&
           face_min_screenspace_y <= p->uViewportW &&
-          sub_424829(num_vertices, &nodes[num_nodes].field_C, &p->field_C, uFaceID))
+          isVisibleRoom(num_vertices, &nodes[num_nodes].field_C, &p->field_C, uFaceID))
         {
           //v17 = v39;
           v18 = pFace->uSectorID;
@@ -1546,7 +1546,7 @@
           && v23 <= *((short *)v20 + 2007)
           && v12 >= *((short *)v20 + 2006)
           && v22 <= *((short *)v20 + 2008)
-          && sub_424829(v10, &v3->nodes[v3->num_nodes].field_C, (BspRenderer_stru2 *)(v20 + 4020), uFaceID) )
+          && isVisibleRoom(v10, &v3->nodes[v3->num_nodes].field_C, (BspRenderer_stru2 *)(v20 + 4020), uFaceID) )
         {
           v16 = v21->uSectorID;
           if ( *((short *)v20 + 2004) == v16 )
@@ -1605,7 +1605,7 @@
         v3 = sub_423B5D(v2);
         if ( v3 )
         {
-          if ( sub_424829(v3, &stru_F8A590, pBLVRenderParams->field_7C, v1) )
+          if ( isVisibleRoom(v3, &stru_F8A590, pBLVRenderParams->field_7C, v1) )
           {
             v4 = stru_F8A590._viewport_space_y;
             v5 = pBLVRenderParams->pRenderTarget;