resource: extract.py: pass directory of unpacked Minecraft JAR, not f…

…ull path to assets

Make the script easier to use, and more consistent with sign_textures.py.

resource/README.md

@@ -43,7 +43,7 @@ with MinedMap's resource metadata.
 5. Edit `blocks.json` until the following command passes without errors:
 
      ```sh
-     ./extract.py blocks.json data/new/assets/minecraft/textures/block colors.json
+     ./extract.py blocks.json data/new colors.json
      ```
 
    If possible, the top texture of blocks should be used where different sides

resource/extract.py

@@ -11,7 +11,7 @@
 	sys.exit('Usage: extract.py <blocks.json> <asset directory> <colors.json>')
 
 def mean_color(texture):
-	path = os.path.join(sys.argv[2], texture + '.png')
+	path = os.path.join(sys.argv[2], 'assets/minecraft/textures/block', texture + '.png')
 	im = Image.open(path)
 
 	data = im.convert('RGBA').getdata()