gistfile1.diff

diff --git a/src/nodedef.cpp b/src/nodedef.cpp
index 560c609..92c1d9d 100644
--- a/src/nodedef.cpp
+++ b/src/nodedef.cpp
@@ -678,6 +678,8 @@ class CNodeDefManager: public IWritableNodeDefManager
                                f->special_tiles[j].material_flags = 0;
                                if(f->tiledef_special[j].backface_culling)
                                        f->special_tiles[j].material_flags |= MATERIAL_FLAG_BACKFACE_CULLING;
+                               else
+                                       assert(0);
                                if(f->tiledef_special[j].animation.type == TAT_VERTICAL_FRAMES)
                                        f->special_tiles[j].material_flags |= MATERIAL_FLAG_ANIMATION_VERTICAL_FRAMES;
                                // Animation parameters