--- a/undermine/game.py	Sat Apr 26 20:55:18 2014 +0200
+++ b/undermine/game.py	Sat Apr 26 21:15:52 2014 +0200
@@ -10,6 +10,16 @@
 import undermine.sprites
 
 
+MAP_DIRT, MAP_TUNNEL, MAP_BOULDER, MAP_GEM, MAP_PLAYER = range(5)
+TILES = {
+    MAP_DIRT: 8,
+    MAP_TUNNEL: 11,
+    MAP_BOULDER: 11,
+    MAP_GEM: 11,
+    MAP_PLAYER: 11,
+}
+
+
 class Game(object):
     def __init__(self, fps=24, map_size=(12, 12)):
         self.fps = fps
@@ -24,23 +34,22 @@
         if not (0 <= x + dx <= len(self.map[0]) and
                 0 <= y +dy < len(self.map)):
             return
-        if self.map[y + dy][x + dx] == 2:
+        if self.map[y + dy][x + dx] == MAP_BOULDER:
             return
         self.hero.animations.append(self.hero.move_anim(dx, dy))
         self.hero.place((x + dx, y + dy), False)
-        self.dig((x + dx, y + dy))
-        self.map[y][x] = 1
+        if self.map[y + dy][x + dx] in (MAP_DIRT, MAP_GEM):
+            self.dig((x + dx, y + dy))
+        self.map[y + dy][x + dx] = MAP_PLAYER
+        self.map[y][x] = MAP_TUNNEL
 
     def dig(self, (x, y)):
-        if self.map[y][x]:
-            return
-        self.map[y][x] = 4
-        self.display.background.blit(self.images[11], (x * 64, y * 64))
+        self.display.background.blit(self.images[TILES[MAP_TUNNEL]],
+                                     (x * 64, y * 64))
         dirt = undermine.sprites.Dirt(self.images)
         dirt.place((x, y))
         self.display.back_sprites.add(dirt)
 
-
     def make_map(self, map_size):
         self.boulders = []
         squares = []
@@ -54,26 +63,26 @@
         self.hero = undermine.sprites.Hero(self.images)
         self.hero.place(squares.pop())
         self.display.sprites.add(self.hero)
-        self.map[self.hero.pos[1]][self.hero.pos[0]] = 1
+        self.map[self.hero.pos[1]][self.hero.pos[0]] = MAP_PLAYER
         for i in range(8):
             boulder = undermine.sprites.Boulder(self.images[4])
             x, y = squares.pop()
             boulder.place((x, y))
             self.display.sprites.add(boulder)
             self.boulders.append(boulder)
-            self.map[y][x] = 2
+            self.map[y][x] = MAP_BOULDER
         for i in range(4):
             gem = undermine.sprites.Gem(self.images[5])
             x, y = squares.pop()
             gem.place((x, y))
             self.display.sprites.add(gem)
             self.boulders.append(gem)
-            self.map[y][x] = 3
+            self.map[y][x] = MAP_GEM
 
     def draw_map(self):
         for y, row in enumerate(self.map):
             for x, tile in enumerate(row):
-                self.display.background.blit(self.images[tile + 8],
+                self.display.background.blit(self.images[TILES[tile]],
                                              (x * 64, y * 64))
 
     def update_boulders(self):
@@ -82,10 +91,10 @@
             if boulder.animations:
                 continue
             x, y = boulder.pos
-            if y + 1 < len(self.map) and self.map[y + 1][x] == 1:
+            if y + 1 < len(self.map) and self.map[y + 1][x] == MAP_TUNNEL:
                 boulder.animations.append(boulder.fall_anim())
                 self.map[y + 1][x] = self.map[y][x]
-                self.map[y][x] = 1
+                self.map[y][x] = MAP_TUNNEL
                 boulder.place((x, y +1), False)
 
     def run(self):

Binary file undermine/undermine.png has changed