def create(self):
assert not self.grow
assert not self.body
assert not self.direction
# try to spawn snake at some distance from world's borders
distance = settings.INIT_LENGTH + settings.INIT_MIN_DISTANCE_BORDER
x = randint(distance, World.SIZE_X - distance)
y = randint(distance, World.SIZE_Y - distance)
self.direction = self.current_direction = self.DIRECTIONS[randint(
0, 3)]
# create snake from tail to head
render = []
pos = Position(x, y)
for i in range(0, settings.INIT_LENGTH):
target = self._world[pos.y][pos.x]
if target.char != self.CH_VOID:
raise SnakePlacementError(
'Cannot place snake on %r because the position '
'is occupied by %r', pos, target)
if i == 0:
char = self.CH_TAIL
elif i == settings.INIT_LENGTH - 1:
char = self.CH_HEAD
else:
char = self.CH_BODY
self.body.appendleft(pos)
render.append(Draw(pos.x, pos.y, char, self.color))
pos = self.next_position()
return render
def render_new_snake(self):
# try to spawn snake at some distance from world's borders
distance = settings.INIT_LENGHT + 2
x = randint(distance, settings.FIELD_SIZE_X - distance)
y = randint(distance, settings.FIELD_SIZE_Y - distance)
self.direction = self.DIRECTIONS[randint(0, 3)]
# create snake from tail to head
render = []
pos = Position(x, y)
for i in range(0, settings.INIT_LENGHT):
self.snake.appendleft(pos)
if i == 0:
char = self.TAIL_CHAR
elif i == settings.INIT_LENGHT - 1:
char = self.HEAD_CHAR
else:
char = self.BODY_CHAR
render.append(Draw(pos.x, pos.y, char, self.color))
pos = self.next_position()
return render
def next_position(self):
# next position of the snake's head
return Position(self.snake[0].x + self.direction.xdir,
self.snake[0].y + self.direction.ydir)