Shorten the tail every 3 steps

buba/animations/snake.py

@@ -13,6 +13,7 @@ class SnakeAnimation(BubaAnimation):
         self.width = 20
         self.height = 4
         self.grid = []
+        self.body = []
         # 0:Space
         self.charset = " "
         # 1:up 2:right 3:down 4:left
@@ -37,10 +38,12 @@ class SnakeAnimation(BubaAnimation):
         x = random.randrange(self.width)
         y = random.randrange(self.height)
         d = random.randrange(4)
-        self.grid[y][x] = 1 + d
         for r in range(self.height):
             self.buba.simple_text(0, r, 0, "") # clear display
+        self.grid[y][x] = 1 + d
+        self.body.append((x, y))
         self.render()
+        iterations = 0
         while True:
             if self.is_blocked(x, y, d):
                 end = True
@@ -59,6 +62,13 @@ class SnakeAnimation(BubaAnimation):
                 self.grid[y][x] = 5 + (d % 2)
             (x, y) = self.next(x, y, d)
             self.grid[y][x] = 1 + d
+            iterations += 1
+            self.body.append((x, y))
+            if iterations % 3 == 0:
+                (tx, ty) = self.body.pop(0)
+                self.grid[ty][tx] = 0
+                (tx, ty) = self.body[0]
+                self.grid[ty][tx] = 11
             self.render()
             sleep(0.5)
         sleep(5)