An optimized tic-tac-toe game.
This game is an on-chain tictactoe game, where minters play against each other . The is just a project I created while learning bits manipulations.
Tic-tac-toe is a 2 player game where players take turns to make a finite amount of moves until either all moves has been exhausted (its a draw) or a player has won. Here is a typical tic-tac-toe game.
# an empty game # game where play x won
[ ] [ ] [ ] [x] [ ] [o]
[ ] [ ] [ ] [ ] [x] [o]
[ ] [ ] [ ] [o] [ ] [x] # Win is diagonal
# a draw
[x] [x] [o]
[o] [x] [x]
[x] [o] [o]
From the example above, 2 players are represented using to letters X and O and each take turns to win and also prevent the other player from winning.
So here is how we'd store a game in bits
21 bits for each game
00 00 00 |
00 00 00 |= first 18 bits [000000000000000000]
00 00 00 |
[00] [0] [00 00 00 00 00 00 00 00 00]
------ ------ ------------------------------
STATE TURN BOARD
When a player chooses to make a move he'd choose which place to play the move and indicate that it's the next players turn. Each move would be represented by a number like so:
[0] [1] [2] | => { [8] [7] [6] [5] [4] [3] [2] [1] [0] }
[3] [4] [5] | --------------------------------------
[6] [7] [8] | BOARD
So typically a game play would be:
Given that player1 is X and player2 is O
- player1 makes more 0
- player2 makes more 4
- player1 makes more 3
- player2 makes more 6
- player1 makes more 1
- player2 makes more 2
[x1] [x3] [o3]
[x2] [o1] [ ]
[o2] [ ] [ ]
player 2 won :)
Now, players can make moves and switch turns but they'd keep playing if we don't stop them when a player has won or it's a draw. So a player's win can either be HORIZONTAL, VERTICAL or DIAGONAL. Representing these in the board would look like:
HORIZONTAL_MASK = 0x3f
11 11 11 |
00 00 00 | => 000000000000111111 = 0x3f
00 00 00 |
These are the HORIZONTAL wins
1. x x x 2. | 0 0 0 3. | 0 0 0
0 0 0 | x x x | 0 0 0
0 0 0 | 0 0 0 | x x x
For player 1
H1. 10 10 10
00 00 00 = 000000000000010101
00 00 00
H2. 00 00 00
10 10 10 = 000000010101000000 : H1 << 6
00 00 00
H3. 00 00 00
00 00 00 = 010101000000000000 : H2 << 6 or H1 << 12
10 10 10
Note: HORIZONTAL_MASK / 3 == H1
VERTICAL_MASK = 0x3f
00 00 11 |
00 00 11 | => 0b11000011000011 = 0x30C3
00 00 11 |
These are the VERTICAL wins
1. x 0 0 2. | 0 x 0 3. | 0 0 x
x 0 0 | 0 x 0 | 0 0 x
x 0 0 | 0 x 0 | 0 0 x
For player 1
V1. 10 00 00
10 00 00 = 000001000001000001
10 00 00
V2. 00 10 00
00 10 00 = 000100000100000100 : V1 << 2
00 10 00
V3. 00 00 10
00 00 10 = 010000010000010000 : V2 << 2 or V1 << 4
00 00 10
Note: VERTICAL_MASK / 3 == V1
11 00 00 |
00 11 00 | => 0b110000001100000011 = 0x30303
00 00 11 |
00 00 11 |
00 11 00 | => 0b1100110011 = 0x3330
11 00 00 |
These are the DIAGONAL wins
1. x 0 0 2. | 0 0 x
0 x 0 | 0 x 0
0 0 x | x 0 0
For player 1
D1. 10 00 00
00 10 00 = 010000000100000001
00 00 10
D2. 00 00 10
00 10 00 = 000001000100010000
10 00 00
BL_TO_TR_DIAGONAL_MASK / 3 == D1
BR_TO_TL_DIAGONAL_MASK / 3 == D2
Python is required.
pip install -r requirements.txt
Deploy Locally and Run Tests using Brownie
brownie run scripts/deploy.py
brownie test