This class creates a snake body and contains methods for movement and extension.
| 10 | UP, DOWN, LEFT, RIGHT = 90, 270, 180, 0 |
| 11 | |
| 12 | class Snake: |
| 13 | """ This class creates a snake body and contains methods for movement and extension. """ |
| 14 | def __init__(self): |
| 15 | self.segments = [] |
| 16 | self.create_snake() |
| 17 | self.head = self.segments[0] |
| 18 | |
| 19 | def create_snake(self): |
| 20 | """ Creates the initial snake body. """ |
| 21 | for position in STARTING_POSITIONS: |
| 22 | self.add_segment(position) |
| 23 | self.segments[0].color(colors.FIRST_SEGMENT_COLOR) |
| 24 | |
| 25 | def add_segment(self, position): |
| 26 | """ Adds a new segment to the snake. """ |
| 27 | new_segment = Turtle(shape="square") |
| 28 | new_segment.penup() |
| 29 | new_segment.goto(position) |
| 30 | new_segment.color(colors.BODY_COLOR) |
| 31 | self.segments.append(new_segment) |
| 32 | |
| 33 | def extend(self): |
| 34 | """ Adds a new segment to the snake's tail. """ |
| 35 | self.add_segment(self.segments[-1].position()) |
| 36 | self.segments[0].color(colors.FIRST_SEGMENT_COLOR) |
| 37 | |
| 38 | def move(self): |
| 39 | """ Moves the snake forward by moving each segment to the position of the one in front.""" |
| 40 | for i in range(len(self.segments) - 1, 0, -1): |
| 41 | x = self.segments[i - 1].xcor() |
| 42 | y = self.segments[i - 1].ycor() |
| 43 | self.segments[i].goto(x, y) |
| 44 | self.head.forward(MOVE_DISTANCE) |
| 45 | |
| 46 | def reset(self): |
| 47 | """Hides the old snake and creates a new one for restarting the game.""" |
| 48 | for segment in self.segments: |
| 49 | segment.hideturtle() |
| 50 | self.segments.clear() |
| 51 | self.create_snake() |
| 52 | self.head = self.segments[0] |
| 53 | |
| 54 | def up(self): |
| 55 | """Turns the snake's head upwards, preventing it from reversing.""" |
| 56 | if self.head.heading() != DOWN: |
| 57 | self.head.setheading(UP) |
| 58 | |
| 59 | def down(self): |
| 60 | """Turns the snake's head downwards, preventing it from reversing.""" |
| 61 | if self.head.heading() != UP: |
| 62 | self.head.setheading(DOWN) |
| 63 | |
| 64 | def left(self): |
| 65 | """Turns the snake's head to the left, preventing it from reversing.""" |
| 66 | if self.head.heading() != RIGHT: |
| 67 | self.head.setheading(LEFT) |
| 68 | |
| 69 | def right(self): |