Merge pull request #2 from procaconsul/open-mouth

Make snake open mouth to consume food

Author: procaconsul

main.py

@@ -46,19 +46,40 @@ def increment_score():
     score += 1
     score_var.set(f"Score: {score}")
 
-def render_point(point, color):
+def render_point(point, color, square=True):
     coord_x, coord_y = point.x * TILE_WIDTH, point.y * TILE_WIDTH
-    canvas.create_rectangle(coord_x, coord_y,
-                            coord_x + TILE_WIDTH,
-                            coord_y + TILE_WIDTH,
-                            fill=color,
-                            outline='white')
+    renderer = canvas.create_rectangle if square else canvas.create_oval
+    return renderer(coord_x, coord_y,
+                    coord_x + TILE_WIDTH,
+                    coord_y + TILE_WIDTH,
+                    fill=color,
+                    outline='white')
 
 def render_food(food):
-    render_point(food, 'red')
+    render_point(food, 'red', square=False)
+
+def render_head(snake):
+    if snake.next_position() == food or snake.head == food:
+        x, y = snake.head
+        x, y = x * TILE_WIDTH, y * TILE_WIDTH
+        midpoint = [x + (TILE_WIDTH / 2), y + (TILE_WIDTH / 2)]
+
+        bbox = [[x, y],
+                [x + TILE_WIDTH, y],
+                [x + TILE_WIDTH, y + TILE_WIDTH],
+                [x, y + TILE_WIDTH]]
+
+        bbox.insert(snake.direction.value + 1, midpoint)
+
+        bbox = [coord for point in bbox for coord in point]
+
+        canvas.create_polygon(bbox, fill="blue", outline="white")
+    else:
+        render_point(snake.head, "blue")
 
 def render_snake(snake):
-    render_point(snake[-1], 'blue')
+    render_head(snake)
+
     for point in snake.tail:
         render_point(point, 'black')
 
@@ -72,15 +93,14 @@ def game_loop():
     else:
         snake.move()
 
-    if snake[-1] in snake.tail:
+    if snake.head in snake.tail:
         text = canvas.create_text(SCREEN_WIDTH/2, SCREEN_WIDTH/2,
                                   fill='black',font='courier 80 bold', 
                                   text=GAME_OVER_MSG)
         text_frame = canvas.create_rectangle(canvas.bbox(text), 
                                              fill='white', 
                                              outline='white')
         canvas.tag_lower(text_frame, text)
-
     else:
         canvas.delete('all')
         render_food(food)

snake.py

@@ -23,16 +23,24 @@ def __getitem__(self, index):
         return list(self.body)[index]
 
     def change_direction(self, new_direction):
-        if new_direction.value + self.direction.value:
+        if not self.direction.is_opposite(new_direction):
           self.direction = new_direction
 
     def move(self, grow=False):
-        tail = self.body[0] if grow else self.body.popleft()
-        x, y = self.body[-1] if len(self.body) else tail
-        d_x, d_y = DIRECTION_VECTOR[self.direction]
-        self.body.append(Point((x + d_x) % self.env_width,
-                          (y + d_y) % self.env_width))
+        new_head = self.next_position()
+        if not grow:
+            self.body.popleft()
+        self.body.append(new_head)
 
+    def next_position(self):
+        x, y = self.head
+        dx, dy = DIRECTION_VECTOR[self.direction]
+        return Point((x + dx) % self.env_width,
+                     (y + dy) % self.env_width)
+
+    @property
+    def head(self):
+        return self[-1]
 
     @property
     def tail(self):

utils.py

@@ -2,9 +2,12 @@
 from collections import namedtuple 
 
 class Direction(Enum):
-    NORTH = 1
-    EAST  = 2
-    SOUTH = -1
-    WEST  = -2
+    NORTH = 0
+    EAST  = 1
+    SOUTH = 2
+    WEST  = 3
+
+    def is_opposite(self, other):
+        return self.value + other.value % 2 == 0
 
 Point = namedtuple('Point', 'x, y')