added an option to delete caches

gmap.py

@@ -11,7 +11,7 @@ import world
 import quadtree
 
 helptext = """
-%prog [-p PROCS] <Path to World> <tiles dest dir>
+%prog [-p PROCS] [-d] <Path to World> <tiles dest dir>
 """
 
 def main():
@@ -21,6 +21,7 @@ def main():
         cpus = 1
     parser = OptionParser(usage=helptext)
     parser.add_option("-p", "--processes", dest="procs", help="How many chunks to render in parallel. A good number for this is the number of cores in your computer. Default %s" % cpus, default=cpus, action="store", type="int")
+    parser.add_option("-d", "--delete", dest="delete", help="Clear all caches. Next time you render your world, it will have to start completely over again. This is probably not a good idea for large worlds. Use this if you change texture packs and want to re-render everything.", action="store_true")
 
     options, args = parser.parse_args()
 
@@ -34,6 +35,9 @@ def main():
         parser.error("Where do you want to save the tiles?")
     destdir = args[1]
 
+    if options.delete:
+        return delete_all(worlddir, destdir)
+
     # First generate the world's chunk images
     w = world.WorldRenderer(worlddir)
     w.go(options.procs)
@@ -42,5 +46,25 @@ def main():
     q = quadtree.QuadtreeGen(w, destdir)
     q.go(options.procs)
 
+def delete_all(worlddir, tiledir):
+    # First delete all images in the world dir
+    imgre = r"img\.[^.]+\.[^.]+\.nocave\.\w+\.png$"
+    matcher = re.compile(imgre)
+
+    for dirpath, dirnames, filenames in os.walk(worlddir):
+        for f in filenames:
+            if matcher.match(f):
+                filepath = os.path.join(dirpath, f)
+                print "Deleting {0}".format(filepath)
+                os.unlink(filepath)
+
+    # Now delete all /hash/ files in the tile dir.
+    for dirpath, dirnames, filenames in os.walk(tiledir):
+        for f in filenames:
+            if f.endswith(".hash"):
+                filepath = os.path.join(dirpath, f)
+                print "Deleting {0}".format(filepath)
+                os.unlink(filepath)
+
 if __name__ == "__main__":
     main()