Only pass the part of the dict we need to the chunk renderer

chunk.py

@@ -112,12 +112,12 @@ def iterate_chunkblocks(xoff,yoff):
 transparent_blocks = set([0, 6, 8, 9, 18, 20, 37, 38, 39, 40, 44, 50, 51, 52, 53,
     59, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 74, 75, 76, 77, 78, 79, 81, 83, 85])
 
-def render_and_save(chunkfile, cachedir, worldobj, cave=False, queue=None):
+def render_and_save(chunkfile, cachedir, worldobj, cached, cave=False, queue=None):
     """Used as the entry point for the multiprocessing workers (since processes
     can't target bound methods) or to easily render and save one chunk
     
     Returns the image file location"""
-    a = ChunkRenderer(chunkfile, cachedir, worldobj, queue)
+    a = ChunkRenderer(chunkfile, cachedir, worldobj, cached, queue)
     try:
         return a.render_and_save(cave)
     except ChunkCorrupt:
@@ -140,7 +140,7 @@ class ChunkCorrupt(Exception):
     pass
 
 class ChunkRenderer(object):
-    def __init__(self, chunkfile, cachedir, worldobj, queue):
+    def __init__(self, chunkfile, cachedir, cached, worldobj, queue):
         """Make a new chunk renderer for the given chunkfile.
         chunkfile should be a full path to the .dat file to process
         cachedir is a directory to save the resulting chunk images to
@@ -169,7 +169,7 @@ class ChunkRenderer(object):
         moredirs, dir2 = os.path.split(destdir)
         _, dir1 = os.path.split(moredirs)
         self.cachedir = os.path.join(cachedir, dir1, dir2)
-        self.dirbits = (dir1, dir2)
+        self.cached = cached
 
 
         if self.world.useBiomeData:
@@ -304,9 +304,9 @@ class ChunkRenderer(object):
     def find_oldimage(self, cave):
         # Get the name of the existing image.
         oldimg = oldimg_path = None
-        key = ".".join((self.dirbits[0], self.dirbits[1], self.blockid, "cave" if cave else "nocave"))
-        if key in self.world.cached:
-             oldimg_path = self.world.cached[key]
+        key = ".".join((self.blockid, "cave" if cave else "nocave"))
+        if key in self.cached:
+             oldimg_path = self.cached[key]
              _, oldimg = os.path.split(oldimg_path)
              logging.debug("Found cached image {0}".format(oldimg))
         return oldimg, oldimg_path

world.py

@@ -36,6 +36,7 @@ and for extracting information about available worlds
 """
 
 base36decode = functools.partial(int, base=36)
+cached = collections.defaultdict(dict)
 
 
 def _convert_coords(chunks):
@@ -108,7 +109,6 @@ class WorldRenderer(object):
             textures.prepareBiomeData(worlddir)
 
         self.chunklist = chunklist
-        self.cached = collections.defaultdict(dict)
 
         # In order to avoid having to look up the cache file names in
         # ChunkRenderer, get them all and store them here
@@ -119,8 +119,9 @@ class WorldRenderer(object):
                 dirname, dir_b = os.path.split(root)
                 _, dir_a = os.path.split(dirname)
                 _, x, z, cave, _ = filename.split('.', 4)
-                bits = '.'.join((dir_a, dir_b, x, z, cave))
-                self.cached[bits] = os.path.join(root, filename)
+                dir = '/'.join((dir_a, dir_b))
+                bits = '.'.join((x, z, cave))
+                cached[dir][bits] = os.path.join(root, filename)
 
 
         #  stores Points Of Interest to be mapped with markers
@@ -294,7 +295,11 @@ class WorldRenderer(object):
                         results[(col, row)] = imgpath
                         continue
 
-                result = chunk.render_and_save(chunkfile, self.cachedir, self, cave=self.caves, queue=q)
+                moredirs, dir2 = os.path.split(os.path.dirname(self.chunkfile))
+                dir1 = os.path.basename(moredirs)
+                cachename = '/'.join(dir1, dir2)
+
+                result = chunk.render_and_save(chunkfile, self.cachedir, self, cached[chunkname], queue=q)
                 results[(col, row)] = result
                 if i > 0:
                     try:
@@ -320,8 +325,12 @@ class WorldRenderer(object):
                         results[(col, row)] = imgpath
                         continue
 
+                moredirs, dir2 = os.path.split(os.path.dirname(self.chunkfile))
+                dir1 = os.path.basename(moredirs)
+                cachename = '/'.join(dir1, dir2)
+
                 result = pool.apply_async(chunk.render_and_save,
-                        args=(chunkfile,self.cachedir,self),
+                        args=(chunkfile,self.cachedir,self, cached[chunkname]),
                         kwds=dict(cave=self.caves, queue=q))
                 asyncresults.append((col, row, result))