From 391ba50aea4dee51987354ac227f005b47f1bc67 Mon Sep 17 00:00:00 2001
From: Andrew Chin <achin@eminence32.net>
Date: Tue, 22 Feb 2011 19:08:58 -0500
Subject: [PATCH] Provide a nice error message when run on McRegion'd worlds

---
 world.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/world.py b/world.py
index 1a9f38e..9293ba9 100644
--- a/world.py
+++ b/world.py
@@ -112,6 +112,14 @@ class WorldRenderer(object):
         self.cachedir = cachedir
         self.useBiomeData = useBiomeData
 
+        # figure out chunk format is in use
+        # if mcregion, error out early until we can add support
+        data = nbt.load(os.path.join(self.worlddir, "level.dat"))[1]['Data']
+        #print data
+        if 'version' in data and data['version'] == 19132:
+            logging.error("Sorry, Minecraft-Overviewer doesn't yet know how to read McRegion chunks")
+            sys.exit(1)
+
         if self.useBiomeData:
             textures.prepareBiomeData(worlddir)