Snake bot for tournament AI Bot Battles

Local testing

1. Configuration

• Config file is src/constants.py

2. Test game between 2 bots

$ python playGame.py --show <delay in seconds> --output <path to json output file> <path to bot1> <path to bot2> 

• Example

$ python playGame.py --show 0.1 aibb2021_snake_bot.py enemy_bot.py

Getting started with Snake-bot

In order to start programming your bot, first, you need to import IBot class from the src.bot module.

from src.bot import IBot

Then you need to create your own class Bot inherited from IBot and create a constructor in the following way to initialize your bot properly.

class Bot(IBot):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

The constructor may be extended with additional functionality. E.g. you can initialize there some initial state of your bot.

It is assumed that your class will implement the following method:

def chooseDirection(self, snake, opponent, mazeSize, apple)

It will be called on every game iteration by the checker. The method must plan the next step of the snake based on the following information about the game field:

• snake is an object of the class Snake from src.snake module
• opponent is an object of the class Snake from src.snake module
• mazeSize is a tuple (an object of the class src.geometry.Coordinate) which contains the height and width of the game field (for IOAI tournament the field size will 14 by 14).
• apple is a tuple (src.geometry.Coordinate) with coordinates of the apple: apple.x and apple.y.

The method must return the direction the snake must move in on the next step. The direction must be one of the following objects: src.geometry.DOWN, src.geometry.UP, src.geometry.LEFT, src.geometry.RIGHT.

The checker assumes that your method does not take more than 1 second to perform the next . If the execution time of the method exceeds 1 second, the bot loses the game. So, if your bot is doing heavy calculations you need to write a code that manage the execution time to return from the method in a proper moment.

Here is an example of a bot that makes only 3 steps and finish the game.

from src.bot import IBot
from src.geometry import Direction, Coordinate, RIGHT
from src.snake import Snake

STEPS_TO_MOVE = 3

class Bot(IBot):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.i = 0

    def chooseDirection(self, snake: Snake, opponent: Snake, mazeSize: Coordinate, apple: Coordinate) -> Direction:
        self.i += 1

        if self.i > STEPS_TO_MOVE:
            head = snake.body[0]
            firstBodyElement = snake.body[1]
            directionToDeath = head.getDirection(firstBodyElement)

            return directionToDeath
        else:
            return RIGHT

Conditions for the end of the game

In the beginning, all two snakes are alive.

The game ends when at least one snake is dead

A snake considered dead if at least one of the following conditions is true:

1. The number game iterations (moves) exceeded 500
2. Evaluation of chooseDirection of a snake exceeded 1 second
3. During execution of chooseDirection of a snake, an exception was raised.
4. Method chooseDirection of a snake returned neither UP, DOWN, LEFT, nor RIGHT (variables from src.geometry)
5. A snake went out of the field (head of snake not in 14x14 box)
6. The head of a snake is in the same cell as the body of this snake
7. The head of a snake is in the same cell as the body of opponent snake
8. The head of a snake is in the same cell as the head of opponent snake

If at the end:

• there is live snake, then this snake is the winner
• both snakes are dead, then if they have different lentgh (they ate diffent amount of apples) then the snake that is longer is the winner

Otherwise, we call it draw

Documentation

---

class Direction

Represents direction in changing current coordinate.

from src.geometry import Direction

• there are predefined directions: UP, DOWN, RIGHT and LEFT
• there are list of all predefined directions: directions

>>> from src.geometry import UP, LEFT, DOWN, RIGHT, directions
>>> directions == [UP, DOWN, RIGHT, LEFT]
True

You should return exactly one of the predefined directions in your chooseDirection method

---

class Coordinate

2D point with integer values

from src.geometry import Coordinate
coord = Coordinate(3, 14)

Method:

• moveTo(direction) - returns new coordinate, that has moved in this direction

>>> coord = Coordinate(3, 14)
>>> coord = coord.moveTo(UP)
>>> coord == Coordinate(3, 15)
True

• getDirection(otherCoordinate) - returns predefined direction of vector between two points. if there is no such predefined direction, returns None

>>> Coordinate(3,14).getDirection(Coordinate(3,15))
UP
>>> Coordinate(3,14).getDirection(Coordinate(4,14))
RIGHT
>>> Coordinate(3,14).getDirection(Coordinate(4,15))
>>> 

• inBounds(mazeSize) - returns true if point in maze, false otherwise

>>> coord = Coordinate(4,4)
>>> coord.inBounds(Coordinate(4,5))
False
>>> coord.inBounds(Coordinate(5,5))
True

• getDistance(otherCoordinate) - returns Manhattan distance between two coordinate

>>> Coordinate(1,1).getDistance(Coordinate(5,4))
7

• getMathDistance(otherCoordinate) - returns Euclidean distance between two points (coordinate)

>>> Coordinate(1,1).getMathDistance(Coordinate(10,10))
5

• clone() - creates and returns clone of current Coordinate

---

class Snake

from src.snake import Snake

Attributes:

• body - list of src.geometry.Coordinate objects that represents body of the snake
• elements - is the same as body, but it is a set not list
• head - first element of body

Methods:

• clone() - returns clone of current snake, src.snake.Snake object
• moveTo(direction, grow) - moves the snake to the direction, changes body and elements. Returns true if snake is alive after this move, false otherwise
  • paraments:
    • direction (src.geometry.Direction) - move in this direction
    • grow (bool) - if true than increase length by one after move
• headCollidesWith(otherSnake) - returns true if the head of the current snake is in the body of otherSnake
  • paraments:
    • otherSnake (src.snake.Snake) - snake for collision check

When forming the language pack, the code used in the competitions of the Olympiad in AI at Innopolis University (2021) was used