Author: Normand M. Blais
Date: 20:12:48 09/23/99
Go up one level in this thread
On September 23, 1999 at 22:44:01, leonid wrote:
>On September 23, 1999 at 14:11:57, Normand M. Blais wrote:
>
>>On September 22, 1999 at 15:30:36, Brian Nielsen wrote:
>>
>>>
>>>Hi
>>>
>>>My name is Brian, i was thinking about writing a chess engine for fun.
>>>I am pretty experienced programmer/developper(c++,delpie), but have not been
>>>programming games, thoug i have made a packman clone a couple years ago.
>>>
>>>I have done a little research myself to get the principles in making a chess
>>>engine/program, and i think i now have basic understanding in how to(i hope :-))
>>>
>>>i am curious in how you chessgame programmers represent the chessboard, I have
>>>seen 4-5 different examples/ways in how to do it, how do you do it and why ??
>>>
>>>Second how long time does it take to make a basic engine! from scratch
>>>provided that i am a experienced programmer.
>>>
>>>Best regards
>>>
>>>Brian Nielsen
>>
>>
>>Hi,
>>
>>I'm not using C/C++ (yet) but I thought I could share the idea that I use for
>>my chess program. It is probably not new but I've nerver seen it mentionned any-
>>where. It is easy to understand and to implement. So, just for the record, here
>>it is.
>>
>>
>>
>>preliminary notes: The lower bound for array indexing is 1 (not 0) in the
>> explanation below.
>>
>>1- The board is represented by an array of 64 integers.
>>
>>
>>
>> 1 2 3 4 5 6 7 8 - 8
>> 9 10 11 12 13 14 15 16 - 7
>> 17 18 19 20 21 22 23 24 - 6
>> 25 26 27 28 29 30 31 32 - 5
>> 33 34 35 36 37 38 39 40 - 4
>> 41 42 43 44 45 46 47 48 - 3
>> 49 50 51 52 53 54 55 56 - 2
>> 57 58 59 60 61 62 63 64 - 1
>>
>> A B C D E F G H
>>
>>
>>2- A 64 by 8 integer array is used for the piece movements. For each square,
>> 8 directions is recorded:
>>
>>
>> NW(8) N(1) NE(2)
>> \ | /
>> W(7)--- ----E(3)
>> / | \
>> SW(6) S(5) SE(4)
>>
>> For a given square and a given direction, the index of the adjacent square
>> is stored. If there is no square (case of a border square), 0 is stored.
>>
>> directions: 1 2 3 4 5 6 7 8
>> ---------------------------------------
>> square(1) = 0, 0, 2,10, 9, 0, 0, 0
>> square(2) = 0, 0, 3,11,10, 9, 1, 0
>> .
>> .
>> .
>> square(64) = 56, 0, 0, 0, 0, 0,63,55
>>
>>
>>3- The movement of the pieces are defined in term of directions:
>>
>> Rook --> 1 to 7 by 2
>> Bishop --> 2 to 8 by 2
>> Queen --> 1 to 8 by 1
>> King --> 1 to 8 by 1
>>
>> Knight --> {1,1,2},{1,1,8},{3,3,2},{3,3,4},
>> {5,5,4},{5,5,6},{7,7,6},{7,7,8}
>> White:
>> pawn move one --> 1
>> pawn move two --> {1,1}
>> pawn captures --> 2,8
>>
>> Black:
>> pawn move one --> 5
>> pawn move two --> {5,5}
>> pawn captures --> 4,6
>>
>>4- Enhencements.
>>
>> A 64 by 8 array can be generated for the knight where the squares stored
>> for a given direction is the end square of a knight move. Then the knight
>> movement can be defined this way:
>>
>> Knight --> 1 to 8 by 1
>>
>>
>>
>>Best Regards,
>>
>>Normand M. Blais
>
>This is pretty fascinating for me to find your description of the chess
>board. It had nothing to do with mine. My question to you is: Do your
>representation of the board is usual?
>
>Thanks,
>Leonid.
>boad represention is usual one or something
The way I represent the chess board is not new. What's particular is the way I
generate the moves using an intermediary array to represent directions. I was
able to build a movegenerator in a short time. I compare it to TSCP move
generator and it is as fast if not faster. I know that the bitboard is the way
to go but I'm using an interpreted language that don't have 64bits unsigned
integer data type. I'm programming for fun only.
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