da thang

Snake/Bike.py

@@ -0,0 +1,98 @@
+"""
+
+from trail import SnakeBodySegment
+
+
+
+
+
+class SnakeHead:
+    """An Agent representing the snake's head. When the game starts, you control
+    the snake head using the arrow keys. The SnakeHead always has a direction, and 
+    will keep moving in that direction every turn. When you press an arrow key, 
+    you change the SnakeHead's direction. 
+
+    Attributes:
+        name: "Snake head"
+        position: (0,0) 
+        character: ``'v'`` Depending on the snake head's direction, its character
+            changes to ``'<'``, ``'^'``, ``'>'``, or ``'v'``.
+        next_segment: Initially ``None``, this is a reference to a SnakeBodySegment.
+        growing: When set to True, the snake will grow a new segment on its next move.
+    """
+    RIGHT = (1, 0)
+    UP = (0, -1)
+    LEFT = (-1, 0)
+    DOWN = (0, 1)
+    name = "Snake head"
+    position = (0, 0)
+    direction = DOWN
+    character = 'v'
+    next_segment = None
+    growing = False
+
+    def play_turn(self, game):
+        """On each turn, the snake head uses its position and direction to figure out
+        its next position. If the snake head is able to move there (it's on the board and 
+        not occuppied by part of the snake's body), it moves. 
+
+        Then, if the snake head is on the Apple, the Apple moves to a new random position
+        and ``growing`` is set to True.
+
+        Now we need to deal with two situations. First, if ``next_segment`` is not None, there is 
+        a SnakeBodySegment attached to the head. We need the body to follow the head, 
+        so we call ``self.next_segment.move``, passing the head's old position 
+        (this will be the body's new position), a reference to the game, and a value for 
+        ``growing``. If the snake needs to grow, we need to pass this information along
+        the body until it reaches the tail--this is where the next segment will be attached. 
+
+        If there is no ``next_segment`` but ``self.growing`` is True, it's time to add 
+        a body! We set ``self.next_segment`` to a  new SnakeBodySegment, set its 
+        position to the head's old position, and add it to the game. We also add 1 to the 
+        game's score.
+        """
+        x, y = self.position
+        dx, dy = self.direction
+        if self.can_move((x+dx, y+dy), game):
+            self.position = (x+dx, y+dy)
+            if self.is_on_apple(self.position, game):
+                apple = game.get_agent_by_name("Apple")
+                apple.relocate(game)
+                self.growing = True
+            if self.next_segment:
+                self.next_segment.move((x, y), game, growing=self.growing)
+            elif self.growing:
+                self.next_segment = SnakeBodySegment(1, (x, y))
+                game.add_agent(self.next_segment)
+                game.state['score'] += 1
+            self.growing = False
+
+
+    def handle_keystroke(self, keystroke, game):
+        """Checks whether one of the arrow keys has been pressed. 
+        If so, sets the SnakeHead's direction and character.
+        """
+        x, y = self.position
+        if keystroke.name == "KEY_RIGHT":
+            self.direction = self.RIGHT
+            self.character = '>'
+        elif keystroke.name == "KEY_UP":
+            self.direction = self.UP
+            self.character = '^'
+        elif keystroke.name == "KEY_LEFT":
+            self.direction = self.LEFT
+            self.character = '<'
+        elif keystroke.name == "KEY_DOWN":
+            self.direction = self.DOWN
+            self.character = 'v'
+
+
+    def can_move(self, position, game):
+        on_board = game.on_board(position)
+        empty = game.is_empty(position)
+        on_apple = self.is_on_apple(position, game)
+        return on_board and (empty or on_apple)
+
+    def is_on_apple(self, position, game):
+        apple = game.get_agent_by_name("Apple")
+        return apple.position == position