This would need converting to Blitz.
Hope it helps.
True Basic Source follows:
;Chess - updated 3/2/02 v.102
;This is a simple chess program written in True BASIC
;
;Even the fastest BASIC compiler is incapable of creating an efficient chess
;program. It's the nature of the language. And I don't even try to accomplish that
;here. My goal was simply to create a program that could play sensible chess, and yet
;be comprehensible to someone looking at the code. I've seen too many spaghetti code
;programs, or programs barely able to make legal moves. This program hopefully balances
;coherent code with reasonable play. (For a truly ambitious BASIC chess program, go
;to http://digilander.iol.it/larsenvb/index_e.htm)
;
;Although it contains a graphical interface, this program is no-frills. It will not
;check your moves for legality. It will not let you take back your moves. It will
;not play by a clock. It cannot be forced to make a move before it's ready.
;But hopefully you'll have fun tinkering with it. The source code is free. Use
;however you wish.
;
;ergundel@...
PROGRAM CHESS(PositionCSV$) ; load simple command line CSV file as starting position, if supplied
OPTION TYPO
RANDOMIZE
SET MODE "color256" ; Windows video mode - does nothing in dos
LIBRARY "BTreeLib.trc" ; compiled binary tree routines for searching book moves
LOCAL BookExists
WHEN error in ; If opening book file exits, use, else, ignore
OPEN #1: name "opnbook.bt", create old, access input, org byte
CLOSE #1 ; cause error if file isn't there
CALL BTOpen("opnbook.bt", BookExists, #2)
USE
LET BookExists=0
END WHEN
LOCAL BestFromR(1 to 4), BestFromC(1 to 4), BestToR(1 to 4), BestToC(1 to 4),x,y
LOCAL MaxRow,MaxCol,MaxPlyLevel,MaxExtendedPlys, BoardPic$,BlackSquare$,WhiteSquare$,turn
LOCAL fromX,fromY,toX,toY,mouseoption,besteval,NumberEvaluated, MoveCount
LOCAL MoveList$,BookLine$,note$,found,randx,tmp$,CastleFlag,SelfPlay$,colstr$
LET colstr$="abcdefgh"
DECLARE FUNCTION Notate$
LET CastleFlag=1
PRINT "Press Any Key To Begin, or ""A"" to begin autoplay";
GET KEY x
IF x<255 and ucase$(chr$(x))="A" then
LET SelfPlay$="Y"
IF ucase$(trim$(SelfPlay$))[1:1]="Y" then LET SelfPlay$="Y"
END IF
; Write game to pgn file
OPEN #1: name "game.pgn", org text, create newold, access outin
ERASE #1
; set default level
LET MaxPlyLevel=2
LET MaxExtendedPlys=2 ;ideally, Extended Plys+MaxPlies should be an even number
SET WINDOW 0, 22, -6, 9.5
ASK MAX CURSOR MaxRow,MaxCol ; find window limits
DIM board(1 to 8, 1 to 8)
; Load position from CSV file, else load normal starting position
IF PositionCSV$="" then
; first call merely sets up the board
CALL MakeMove(board,0,0,0,0,0,BestFromR(),BestFromC(),BestToR(),BestToC(),MoveList$,0)
ELSE
PRINT "Reading position from ";PositionCSV$ ; position in CSV, no frills
OPEN #3: name PositionCSV$, org text, create old, access input
MAT INPUT #3: board
CLOSE #3
END IF
CALL drawboard(board,boardpic$,BlackSquare$,WhiteSquare$)
LET turn=-1
LET MoveCount=1
DO
LET NumberEvaluated = 0
SET CURSOR MaxRow-6,1
SET BACK "black"
SET COLOR "white"
; ;; uncomment next block to auto-run two play levels against each other
; IF turn=1 then ;starts with black (changed later before move)
; LET MaxPlyLevel=2
; LET MaxExtendedPlys=2
; ELSE ;white
; LET MaxPlyLevel=2
; LET MaxExtendedPlys=0
; END IF
IF besteval>=70 then
CALL resign
ELSEIF besteval<=-99 then
PRINT "** you lose **"
STOP
ELSE
END IF
IF SelfPlay$<>"Y" then
PRINT "your turn (A-Autoplay, R-Refresh, Q-Quit, Level 1,2,3,4,5,6)";
SOUND 1000,.01
DO ; loop until move is made
DO ; loop through user options
GET MOUSE fromY,fromX,mouseoption
IF key input then
GET KEY x
IF x<256 then
SELECT CASE chr$(x)
CASE "Q","q"
STOP
CASE "A","a"
LET SelfPlay$="Y"
PRINT "Auto-play will start after your next move"
CASE "R","r"
CLEAR
CALL drawboard(board,boardpic$,BlackSquare$,WhiteSquare$)
SET CURSOR MaxRow-6,1
SET COLOR "White"
CASE "1"
PRINT "Setting to play level 1"
LET MaxPlyLevel=2
LET MaxExtendedPlys=0
CASE "2"
PRINT "Setting to play level 2"
LET MaxPlyLevel=2
LET MaxExtendedPlys=2
CASE "3"
PRINT "Setting to play level 3"
LET MaxPlyLevel=3
LET MaxExtendedPlys=0
CASE "4"
PRINT "Setting to play level 4"
LET MaxPlyLevel=3
LET MaxExtendedPlys=1
CASE "5"
PRINT "Setting to play level 5 (analysis)"
LET MaxPlyLevel=4
LET MaxExtendedPlys=0
CASE "6"
PRINT "Setting to play level 6 (analysis)"
LET MaxPlyLevel=4
LET MaxExtendedPlys=2
CASE else
END SELECT
END IF
END IF
LOOP until mouseoption = 1
DO
GET MOUSE toY,toX,mouseoption
LOOP until mouseoption = 3
LET fromX=int(fromX)
LET fromY=int(fromY)
LET toX=int(toX)
LET toY=int(toY)
IF max(toX,max(toY,max(fromX,fromY)))<=8 and min(toX,min(toY,min(fromX,fromY)))>=1 and (fromX-toX<>0 or fromY-toY<>0) then
WHEN error in
IF MoveCount=int(MoveCount) then
PRINT #1: trim$(str$(MoveCount)) & ". "& Notate$(fromX,fromY,toX,toY);" ";
ELSE
PRINT #1: Notate$(fromX,fromY,toX,toY)
END IF
LET MoveCount=MoveCount+0.5
USE
END WHEN
EXIT DO
END IF
LOOP
LET MoveList$=MoveList$ & Notate$(fromX,fromY,toX,toY)
SET CURSOR MaxRow-6,1
PRINT repeat$(" ",80) ; blank line, clear out old text
IF fromY<>toY and abs(board(fromX,fromY))=1 and board(toX,toY)=0 then ; au passant
LET board(fromX,toY)=0
IF mod(toY+fromX,2)=1 then
BOX SHOW WhiteSquare$ at fromX,toY
ELSE
BOX SHOW BlackSquare$ at fromX,toY
END IF
END IF
LET board(toX,toY)=board(fromX,fromY)
; set castling flags, if moved piece is king or rook
IF CastleFlag<210 and ((abs(board(fromX,fromY))=5 and (fromX*fromY=1 or fromX*fromY=8 or fromX*fromY=64)) or (abs(board(fromX,fromY))=99 and (fromX=1 or fromX=8) and fromY=5)) then CALL SetCastleFlag(fromX,fromY,CastleFlag)
LET board(fromX,fromY)=0
IF abs(board(toX,toY))=1 and (toX=1 or toX=8) then LET board(toX,toY)=9*board(toX,toY) ; pawn to queen
CALL MovePics(fromX,fromY,toX,toY,BlackSquare$,WhiteSquare$,board(toX,toY))
; Castle
IF abs(board(toX,toY)) = 99 and abs(fromY-toY)=2 then
IF toY=7 then
LET fromY=8
LET toY=6
ELSE
LET fromY=1
LET toY=4
END IF
LET board(toX,toY)=board(fromX,fromY)
LET board(fromX,fromY)=0
IF abs(board(toX,toY))=1 and (toX=1 or toX=8) then LET board(toX,toY)=9*board(toX,toY) ; pawn to queen
CALL MovePics(fromX,fromY,toX,toY,BlackSquare$,WhiteSquare$,board(toX,toY))
END IF
ELSE
LET turn = -turn
END IF
IF BookExists<>0 then ; get bookmoves
CALL GetNearest(MoveList$, BookLine$, #2)
LET note$="In Book"
LET tmp$=BookLine$
IF len(MoveList$)<=24 then LET randx=int(rnd*3000/(1+len(MoveList$))) else LET randx=int(rnd*5)
FOR x=1 to randx
CALL GetNext(BookLine$,#2)
IF pos(BookLine$,MoveList$)=0 then
LET BookLine$=tmp$
EXIT FOR
END IF
NEXT x
END IF
IF BookExists=0 or pos(BookLine$,MoveList$)=0 or BookLine$=MoveList$ then
LET note$=""
LET BookExists=0 ; out of book
ELSE
LET BestFromC(MaxPlyLevel)=pos(colstr$,BookLine$[len(MoveList$)+1:len(MoveList$)+1])
LET BestFromR(MaxPlyLevel)=val(BookLine$[len(MoveList$)+2:len(MoveList$)+2])
LET BestToC(MaxPlyLevel) =pos(colstr$,BookLine$[len(MoveList$)+3:len(MoveList$)+3])
LET BestToR(MaxPlyLevel) =val(BookLine$[len(MoveList$)+4:len(MoveList$)+4])
LET MoveList$=MoveList$ & BookLine$[len(MoveList$)+1:len(MoveList$)+4]
END IF
IF BookExists=0 then
CALL MakeMove(board(,),MaxPlyLevel,MaxExtendedPlys,turn,besteval,NumberEvaluated,BestFromR(),BestFromC(),BestToR(),BestToC(),MoveList$,CastleFlag)
LET MoveList$=MoveList$ & Notate$(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel),BestToR(MaxPlyLevel),BestToC(MaxPlyLevel))
SET CURSOR MaxRow-5,1
PRINT "My Move: "&MoveList$[len(MoveList$)-3:maxnum]&" "
END IF
IF BestFromR(MaxPlyLevel)=0 then CALL resign
IF abs(board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel)))=1 and (BestToR(MaxPlyLevel)=1 or BestToR(MaxPlyLevel)=8) then LET board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel))=9*board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel)) ; pawn to queen
LET board(BestToR(MaxPlyLevel),BestToC(MaxPlyLevel))=board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel))
CALL MovePics(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel),BestToR(MaxPlyLevel),BestToC(MaxPlyLevel),BlackSquare$,WhiteSquare$,board(BestToR(MaxPlyLevel),BestToC(MaxPlyLevel)))
; set castling flags, if moved piece is king or rook
IF CastleFlag<210 and ((abs(board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel)))=5 and (BestFromR(MaxPlyLevel)*BestFromC(MaxPlyLevel)=1 or BestFromR(MaxPlyLevel)*BestFromC(MaxPlyLevel)=8 or BestFromR(MaxPlyLevel)*BestFromC(MaxPlyLevel)=64)) or (abs(board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel)))=99 and (BestFromR(MaxPlyLevel)=1 or BestFromR(MaxPlyLevel)=8) and BestFromC(MaxPlyLevel)=5)) then CALL SetCastleFlag(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel),CastleFlag)
LET board(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel))=0
; Castle
IF abs(board(BestToR(MaxPlyLevel),BestToC(MaxPlyLevel))) = 99 and abs(BestFromC(MaxPlyLevel)-BestToC(MaxPlyLevel))=2 then
IF BestToC(MaxPlyLevel)=7 then
LET fromY=8
LET toY=6
ELSE
LET fromY=1
LET toY=4
END IF
LET board(BestFromR(MaxPlyLevel),toY)=board(BestFromR(MaxPlyLevel),fromY)
LET board(BestFromR(MaxPlyLevel),fromY)=0
CALL MovePics(BestFromR(MaxPlyLevel),fromY,BestFromR(MaxPlyLevel),toY,BlackSquare$,WhiteSquare$,board(BestFromR(MaxPlyLevel),toY))
END IF
IF key input then LET SelfPlay$="" ; stop auto-play if key is pressed
WHEN error in
IF MoveCount=int(MoveCount) then
PRINT #1: trim$(str$(MoveCount)) & ". "& Notate$(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel),BestToR(MaxPlyLevel),BestToC(MaxPlyLevel));" ";
ELSE
PRINT #1: Notate$(BestFromR(MaxPlyLevel),BestFromC(MaxPlyLevel),BestToR(MaxPlyLevel),BestToC(MaxPlyLevel))
END IF
USE
END WHEN
LET MoveCount=MoveCount+.5
LOOP
END
;___________________________________________________________________________________________________
; Main routine, accepting as input values board, MaxPlyLevel,MaxExtendedPlys,turn,MoveList$,CastleFlag
; BestFromR(),BestFromC(),BestToR(),BestToC(),besteval,NumberEvaluated (positions)
SUB MakeMove(board(,),MaxPlyLevel,MaxExtendedPlys,turn,besteval,NumberEvaluated,BestFromR(),BestFromC(),BestToR(),BestToC(),MoveList$,CastleFlag)
LOCAL PlyLevel, z, y, a$
LOCAL CurrentFromR(1 to 4), CurrentFromC(1 to 4), CurrentToR(1 to 4), CurrentToC(1 to 4), no_more_moves
LOCAL CurrentEval, EvenOddSwitch
LET EvenOddSwitch=sgn(mod(MaxPlyLevel,2)-0.5)
RESTORE
DIM directions(1 to 32) ; Array of directions from which a square may be attacked (in row/column pairs)
DATA -1,-2, 1,-2, -1,2, 1,2 ; knight moves
DATA -2,-1, 2,-1, -2,1, 2,1
DATA 0, 1, 1, 1, 1,0, 1,-1 ; eight directions
DATA 0,-1, -1,-1, -1,0, -1,1
MAT READ directions
LET no_more_moves = -100 ; constant
LET besteval=-turn*maxnum
IF turn=0 then
CALL setupboard(board)
ELSE
LET PlyLevel=MaxPlyLevel
CALL scanmoves(PlyLevel+1,board(,),0,0,0,0,turn,BestFromR(),BestFromC(),BestToR(),BestToC(),besteval,CastleFlag)
END IF
;___________________________________________________________________________________________________
SUB scanmoves(PlyLevel_,board_(,),SubFromR_,SubFromC_,SubToR_,SubToC_, turn_,BestFromR_(),BestFromC_(),BestToR_(),BestToC_(), BestEval_,CastleFlag_)
DECLARE FUNCTION PosEval,AskCastleFlag,attacked
IF abs(besteval_)>9999 then LET besteval_=(turn_)*maxnum
LOCAL PlyLevel,board(8,8), new_r, new_c, num, SubFromR, SubFromC, rcount,ccount, x,y, BestEval
LOCAL BestFromR(4),BestFromC(4),BestToR(4),BestToC(4),CastleFlag,LostKingFlag,TotalNumberPositions
LOCAL king_r,king_c
FOR y=1 to 8 ; make a copy of the board as if passed by value
FOR x=1 to 8
IF board_(x,y)<>0 then
IF board_(x,y)=turn*99 then
LET king_r=x
LET king_c=y
END IF
END IF
LET board(x,y) = board_(x,y)
NEXT x
NEXT y
LET CastleFlag=CastleFlag_
; make move if square is empty, or opposite colored (exception - pawn can't take by pushing forward
IF PlyLevel_<=MaxPlyLevel and (board(SubToR_,SubToC_)=0 Or (Sgn(board(SubToR_,SubToC_))<>Sgn(board(SubFromR_,SubFromC_)) And (Abs(board(SubFromR_,SubFromC_))<>1 Or SubFromC_<>SubToC_))) then
LET board(SubToR_,SubToC_)=board(SubFromR_,SubFromC_)
;pawn to queen
IF abs(board(SubToR_,SubToC_))=1 and (SubToR_=1 or SubToR_=8) then LET board(SubToR_,SubToC_)=9*board(SubToR_,SubToC_)
; set castling flags, if moved piece is king or rook
IF CastleFlag<210 and ((abs(board(SubFromR_,SubFromC_))=5 and (SubFromR_*SubFromC_=1 or SubFromR_*SubFromC_=8 or SubFromR_*SubFromC_=64)) or (abs(board(SubFromR_,SubFromC_))=99 and (SubFromR_=1 or SubFromR_=8) and SubFromC_=5)) then CALL SetCastleFlag(SubFromR_,SubFromC_,CastleFlag)
LET board(SubFromR_,SubFromC_)=0
LET CurrentFromR(PlyLevel_)= SubFromR_
LET CurrentFromC(PlyLevel_)= SubFromC_
LET CurrentToR(PlyLevel_) = SubToR_
LET CurrentToC(PlyLevel_) = SubToC_
IF abs(board(SubToR_,SubToC_)) = 99 and abs(SubFromC_-SubToC_)=2 then ; Castle
IF SubToC_=7 then
LET board(SubToR_,6)=board(SubFromR_,8)
LET board(SubFromR_,8)=0
ELSE
LET board(SubToR_,4)=board(SubFromR_,1)
LET board(SubFromR_,1)=0
END IF
END IF
IF SubFromR_=king_r and SubFromC_=king_c then
LET king_r=SubToR_
LET king_c=SubToC_
END IF
; checked, but not checked-king's turn (or king missing)
IF king_r=0 or (-turn_=sgn(board(king_r,king_c)) and attacked(board(,),king_r,king_c,turn)=1) then
EXIT SUB
END IF
ELSEIF PlyLevel_<=MaxPlyLevel then ; illegal move, skip move-line
EXIT SUB
ELSE
END IF
IF PlyLevel_=1 Then ; End of recursive search; eval current position
; if move is a capture (not pawn), add plys until no longer a capture
IF MaxExtendedPlys<>0 and (((sgn(board_(CurrentToR(1),CurrentToC(1)))=-sgn(board_(CurrentFromR(1),CurrentFromC(1)))))) and (abs(board_(CurrentFromR(1),CurrentFromC(1)))<>1 or abs(board_(CurrentToR(1),CurrentToC(1)))<>1) then
LOCAL BestFromRx(1),BestFromCx(1),BestToRx(1),BestToCx(1),boardx(0,0)
MAT boardx = board
CALL MakeMove(boardx(,),1,MaxExtendedPlys-1,1*turn_,CurrentEval,0,BestFromRx(),BestFromCx(),BestToRx(),BestToCx(),MoveList$,CastleFlag)
ELSEIF MaxExtendedPlys=0 and (((sgn(board_(CurrentToR(1),CurrentToC(1)))=-sgn(board_(CurrentFromR(1),CurrentFromC(1)))))) and (abs(board_(CurrentFromR(1),CurrentFromC(1)))<>1 or abs(board_(CurrentToR(1),CurrentToC(1)))<>1) then
LET CurrentEval=PosEval(board, turn_)
; if exchange at end of search, and taking piece is undefended, penalize
IF attacked(board,CurrentToR(1),CurrentToC(1),sgn(board(CurrentToR(1),CurrentToC(1))))=1 and attacked(board,CurrentToR(1),CurrentToC(1),-sgn(board(CurrentToR(1),CurrentToC(1))))<>1 then
LET CurrentEval=CurrentEval - 0.72 * board(CurrentToR(1),CurrentToC(1))
END IF
ELSE
LET CurrentEval=PosEval(board, turn_)
END IF
IF EvenOddSwitch*turn*CurrentEval>EvenOddSwitch*turn*BestEval_ then
LET BestEval_=CurrentEval
FOR x=1 to MaxPlyLevel
LET BestFromR_(x)= CurrentFromR(x)
LET BestFromC_(x)= CurrentFromC(x)
LET BestToR_(x) = CurrentToR(x)
LET BestToC_(x) = CurrentToC(x)
NEXT x
END IF
EXIT SUB
ELSEIF PlyLevel_=MaxPlyLevel and maxplylevel<>1 then
CALL info(BestFromR_(),BestFromC_(),BestToR_(),BestToC_(),NumberEvaluated,besteval_,"",MaxPlyLevel)
END IF
LET besteval=(turn_)*maxnum ; always start with the highest value for other side
LET PlyLevel = PlyLevel_ -1
FOR rcount=1 To 8
FOR ccount=1 To 8
IF board(rcount,ccount)<>0 Then ; p
IF Sgn(board(rcount,ccount))=turn_ Then
LET num=1
DO ; repeat thru all possible piece moves
SELECT CASE board(rcount,ccount)
CASE 1, -1 ; pawn
CALL pawnmove(rcount,ccount,num, board(,),1*turn_, new_r, new_c) ; au passant Not yet implemented
CASE 3, -3 ; knight
CALL knightmove(rcount,ccount,num,new_r, new_c)
CASE 3.1, -3.1 ; bishop
CALL bishopmove(rcount,ccount,num,new_r, new_c,board(,))
CASE 5, -5 ; rook
CALL rookmove(rcount,ccount,num,new_r, new_c,board(,),CastleFlag)
CASE 9, -9 ; rook
CALL queenmove(rcount,ccount,num,new_r, new_c,board(,))
CASE 99, -99 ; king
CALL kingmove(rcount,ccount,num,new_r, new_c,board(,),CastleFlag)
END SELECT
IF new_r = no_more_moves then EXIT DO
IF new_r<>0 then
; Recurse down
CALL scanmoves(PlyLevel,board(,),rcount,ccount,new_r, new_c, -1*turn_, BestFromR(),BestFromC(),BestToR(),BestToC(),BestEval,CastleFlag)
; LET TotalNumberPositions=TotalNumberPositions+1
END IF
LET num=num+1
LOOP
END IF
END IF
NEXT ccount
NEXT rcount
IF BestFromR(1)=0 then ; no move found
IF attacked(board_(,),king_r,king_c,turn)=1 then
LET besteval=-turn_*999-turn_*PlyLevel_ ; checkmate seen
ELSE
LET besteval=0 ; stalemate seen
END IF
END IF
IF turn_*BestEval<turn_*BestEval_ then
LET BestEval_ = BestEval ;+ turn_*0.01*TotalNumberPositions
FOR x=1 to maxplylevel
LET BestFromR_(x) = BestFromR(x)
LET BestFromC_(x) = BestFromC(x)
LET BestToR_(x) = BestToR(x)
LET BestToC_(x) = BestToC(x)
NEXT x
END IF
END SUB
;___________________________________________________________________________________________________
; posEval evaluates the current position, with a positive evaluation favoring white
; and a negative eval favoring black. Currently, this routine incorporates very little
; chess knowledge. Improvements in chess knowledge could drastically improve play, and
; might well be worth a small cost in speed.
FUNCTION posEval(board(,), turn)
LOCAL eval, x, y, z, count, PieceCounter, KingOnEdge,wkx,wky,bkx,bky,UseMe
FOR x=1 to 8 ; Simple Material Evaluation
FOR y=1 to 8
LET eval=eval+board(x,y)
IF board(x,y)<>0 then LET PieceCounter=PieceCounter+1
NEXT y
NEXT x
FOR x=1 to 8 ; evaluate pawn values
FOR y=1 to 8
IF board(x,y)<>0 then
IF board(x,y)=1 then
SELECT CASE x
CASE 4 ; fourth row
IF y=4 or y=5 then
LET eval=eval+.1
ELSEIF y=3 or y=6 then
LET eval=eval+.03
ELSE
;no adjustment
END IF
CASE 5
LET eval=eval+.025
CASE 6
LET eval=eval+.2
CASE 7
LET eval=eval+.25
; nothing blocking pawn, and nothing attacking queening square, give bonus
if board(8,y)=0 and attacked(board,8,y,1)=0 then let eval=eval+1
CASE 8
LET eval=eval+9
LET board(x,y)=9
CASE else
; no bonus value
END SELECT
; give bonus for pawn fork
IF y>1 and y<8 and board(x+1,y+1)<-1 and board(x+1,y-1)<-1 then
; but only if pawn is defended (opposite of attacked)
IF attacked(board(,),x,y,-1)=1 then
LET eval=eval+board(x,y) ; increase eval by one pawn's worth
END IF
END IF
ELSEIF board(x,y)=-1 then
SELECT CASE x
CASE 5 ; fourth row, black's perspective
IF y=4 or y=5 then
LET eval=eval-.1
ELSEIF y=3 or y=6 then
LET eval=eval-.03
ELSE
; no adjustment
END IF
CASE 4
LET eval=eval-.025
CASE 3
LET eval=eval-.2
CASE 2
LET eval=eval-.25
; nothing blocking pawn, and nothing attacking queening square, give bonus
if board(1,y)=0 and attacked(board,1,y,-1)=0 then let eval=eval-1
CASE 1
LET eval=eval-9
LET board(x,y)=-9
CASE else
; no bonus value
END SELECT
; give bonus for pawn fork
IF y>1 and y<8 and board(x-1,y+1)>1 and board(x-1,y-1)>1 then
; but only if pawn is defended
IF attacked(board(,),x,y,1)=1 then
LET eval=eval-1 ; increase eval by one pawn's worth
END IF
END IF
ELSEIF abs(board(x,y))=3 then ;knight
IF max(x,y)<7 and min(x,y)>2 then LET eval = eval + sgn(board(x,y)) * 0.3
; check for knight fork
LET count=0
FOR z=1 to 15 step 2
IF min(directions(z)+x,directions(z+1)+y)>=1 and max(directions(z)+x,directions(z+1)+y)<=8 then
IF sgn(board(directions(z)+x,directions(z+1)+y))=-sgn(board(x,y)) then
IF abs(board(directions(z)+x,directions(z+1)+y))>abs(board(x,y)) then
LET count=count+1
END IF
END IF
END IF
NEXT z
; Fork found, give bonus if knight is defended or not attacked
IF count>1 and (attacked(board(,),x,y,-sgn(board(x,y)))=1 or attacked(board(,),x,y,sgn(board(x,y)))=0) then
LET eval=eval+sgn(board(x,y))*0.5
END IF
ELSEIF abs(board(x,y))=3.1 then ;bishop
IF max(x,y)=8 or min(x,y)=1 then LET eval = eval - sgn(board(x,y)) * 0.25
ELSEIF abs(board(x,y))=99 then ;king
IF PieceCounter<6 then
LET UseMe=sgn(board(x,y))
; bonus for being in the middle of the board during endgame for losing side
IF max(x,y)=7 or min(x,y)=2 then LET KingOnEdge=KingOnEdge+sgn(board(x,y))
IF max(x,y)=8 or min(x,y)=1 then LET KingOnEdge=KingOnEdge+2*sgn(board(x,y))
IF sgn(board(x,y))=1 then
LET wkx=x
LET wky=y
ELSE
LET bkx=x
LET bky=y
END IF
FOR z=17 to 32 step 2 ; look all directions around king for places to move
IF max(directions(z)+x,directions(z+1)+y)<=8 and min(directions(z)+x,directions(z+1)+y)>=1 then ;square is on the board
IF sgn(board(directions(z)+x,directions(z+1)+y))=-UseMe then ;opponent's piece in the way
LET eval=eval - UseMe*.1
ELSEIF board(directions(z)+x,directions(z+1)+y)=0 and attacked(board(,),directions(z)+x,directions(z+1)+y,UseMe)=1 then ; square is attacked
LET eval=eval - UseMe*.1
END IF
END IF
NEXT z
END IF
; ; penalty for being checked
; IF turn = sgn(board(x,y)) and attacked(board(,),x,y,turn)=1 then
; LET eval=eval - turn*0.45 ;checked
; elseif -turn = sgn(board(x,y)) and attacked(board(,),x,y,turn)=1 then
; LET eval=eval - turn*88 ;check, but not turn to move
; else
; END IF
;king should stay out of the action before the endgame
IF PieceCounter>12 then
IF board(1,3)=99 or board(1,7)=99 then LET eval=eval+.25
IF board(8,3)=-99 or board(8,7)=-99 then LET eval=eval-.25
IF x<>1 and x<>8 then
LET eval = eval - sgn(board(x,y)) * 0.25
END IF
ELSEIF PieceCounter<8 then
IF max(x,y)=8 or min(x,y)=1 then LET eval=eval - sgn(board(x,y)) * 0.2
;If piece in front of king is the enemy pawn, give bonus
IF y>1 and y<8 and board(x,y+sgn(board(x,y))) = - sgn(board(x,y)) then LET eval=eval + sgn(board(x,y)) * 0.2
;If piece two spaces in front of king is the enemy pawn, give bonus
IF y>2 and y<7 and abs(board(x,y+2*sgn(board(x,y)))) = 99 then LET eval=eval + sgn(board(x,y)) * 0.2
END IF
ELSE
END IF
END IF
NEXT y
NEXT x
IF KingOnEdge<>0 and sgn(KingOnEdge)=-sgn(eval) then LET eval=eval - KingOnEdge ; penalty for king being on edge when behind
IF PieceCounter<5 then LET eval=eval - sgn(eval)* ((abs(wkx-bkx)+abs(wky-bky))/20) ;penalty for being near other king
LET eval=eval + 0.5 * eval*(1 - PieceCounter/32) ; Reward leader for trading down
LET NumberEvaluated = NumberEvaluated +1
LET posEval=eval + rnd/10000 ; randomize move among equal values
END FUNCTION
;___________________________________________________________________________________________________
FUNCTION attacked(board(,),r,c,sign) ; does not include king attacks
LOCAL i,x,y,z
; check for pawn attacks
IF (((sign=1 and r<8 and c<8) or (sign=-1 and r>1 and c<8)) and board(r+sign,c+1)=-sign) or (((sign=1 and r<8 and c>1) or (sign=-1 and r>1 and c>1)) and board(r+sign,c-1)=-sign) then
LET attacked=1
EXIT FUNCTION
END IF
FOR i=1 to 15 step 2 ; check for knight
LET x=directions(i)
LET y=directions(i+1)
IF min(r+y,c+x)>=1 and max(r+y,c+x)<=8 then
IF board(r+y,c+x)=-sign*3 then
LET attacked=1
EXIT FUNCTION
END IF
END IF
NEXT i
FOR i=17 to 31 step 2
LET x=directions(i)
LET y=directions(i+1)
FOR z=1 to 7 ; distance from piece
IF min(r+z*y,c+z*x)>=1 and max(r+z*y,c+z*x)<=8 and board(r+z*y,c+z*x)<>0 then
; IF z=1 and (board(r+y,c+x)= -sign*99 or board(r+y,c+x)= -sign*9 or (x*y<>0 and board(r+y,c+x)= -sign*3.1) or (x*y=0 and board(r+y,c+x)= -sign*5)) then
; LET attacked=1
; ELSE
IF board(r+z*y,c+z*x)= -sign*9 or (x*y<>0 and board(r+z*y,c+z*x)= -sign*3.1) or (x*y=0 and board(r+z*y,c+z*x)= -sign*5) then
LET attacked=1
EXIT FUNCTION
ELSE ;non-attacking piece in direction
EXIT FOR
END IF
END IF
NEXT z
NEXT i
LET attacked = 0
END FUNCTION
;___________________________________________________________________________________________________
SUB pawnmove(row,column,num, board(,),color, move_row, move_column) ; au passant Not yet implemented
SELECT CASE row
CASE 2,7
SELECT CASE column
CASE 1 To 8
SELECT CASE num
CASE 1
LET move_row=row+color
LET move_column=column
CASE 2
IF board(row+color,column)=0 then
LET move_row=row+2*color
IF move_row=9 then LET move_row = 0 ; going wrong direction for 2nd row double push
LET move_column=column
; wrong color to move forward 2 on this row (2 or 7)
ELSEIF board(row+color,column)<>0 or abs(move_row)=9 then
LET move_row=0
END IF
CASE 3
IF column<8 And sgn(board(row+color,column+1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column+1
ELSEIF column>1 And sgn(board(row+color,column-1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column-1
ELSE
LET move_row=0
END IF
CASE 4
IF column>1 And sgn(board(row+color,column-1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column-1
ELSEIF column<8 And sgn(board(row+color,column+1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column+1
ELSE
LET move_row=0
END IF
CASE Else
LET move_row=no_more_moves
END SELECT
END SELECT
CASE 3 To 6 ; third thru sixth row
SELECT CASE column
CASE 1 To 8
SELECT CASE num
CASE 1
LET move_row=row+color
LET move_column=column
CASE 2
IF column<8 And sgn(board(row+color,column+1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column+1
ELSEIF column>1 And sgn(board(row+color,column-1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column-1
ELSE
LET move_row=0
END IF
CASE 3
IF column>1 And sgn(board(row+color,column-1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column-1
ELSEIF column<8 And sgn(board(row+color,column+1))=-sgn(board(row,column)) Then
LET move_row=row+color
LET move_column=column+1
ELSE
LET move_row=0
END IF
CASE Else
LET move_row=no_more_moves
END SELECT
END SELECT
CASE else
LET move_row=no_more_moves
END SELECT
END SUB
;___________________________________________________________________________________________________
SUB KingMove(row,column,num,move_row, move_column,board(,), CastleFlag)
LOCAL IncRow,IncCol ; Direction to move in (-1 or 0 or 1)
SELECT CASE num ;int(num/10)
CASE 1
LET IncRow = +1
LET IncCol = +1
CASE 2
LET IncRow = -1
LET IncCol = -1
CASE 3
LET IncRow = +1
LET IncCol = -1
CASE 4
LET IncRow = -1
LET IncCol = +1
CASE 5
LET IncRow = +1
CASE 6
LET IncRow = -1
CASE 7
LET IncCol = +1
CASE 8
LET IncCol = -1
CASE 9 ; Castle kingside
IF row=1 and board(1,5) = 99 and AskCastleFlag(1,8,CastleFlag)=0 then
IF board(1,6)=0 and board(1,7)=0 and board(1,8)=5 and attacked(board(,),1,5,1)=0 and attacked(board(,),1,6,1)=0 and attacked(board(,),1,7,1)=0 then
LET IncCol = +2
ELSE
LET incCol = +10 ; Make move clearly illegal so will be skipped
END IF
ELSEIF row=8 and board(8,5) =-99 and AskCastleFlag(8,8,CastleFlag)=0 then
IF board(8,6)=0 and board(8,7)=0 and board(8,8)=-5 and attacked(board(,),8,5,-1)=0 and attacked(board(,),8,6,-1)=0 and attacked(board(,),8,7,-1)=0 then
LET IncCol = +2
ELSE
LET incCol = +10
END IF
ELSE
LET incCol = +10
END IF
CASE 10 ; Castle Queenside
IF row=1 and board(1,5) = 99 and AskCastleFlag(1,1,CastleFlag)=0 then
IF board(1,4)=0 and board(1,3)=0 and board(1,2)=0 and board(1,1)=5 and attacked(board(,),1,5,1)=0 and attacked(board(,),1,4,1)=0 and attacked(board(,),1,3,1)=0 then
LET IncCol = -2
ELSE
LET incCol = +10 ; Make move clearly illegal so will be skipped
END IF
ELSEIF row=8 and board(8,5) =-99 and AskCastleFlag(8,1,CastleFlag)=0 then
IF board(8,4)=0 and board(8,3)=0 and board(8,2)=0 and board(8,1)=-5 and attacked(board(,),8,5,-1)=0 and attacked(board(,),8,4,-1)=0 and attacked(board(,),8,3,-1)=0 then
LET IncCol = -2
ELSE
LET incCol = +10
END IF
ELSE
LET incCol = +10
END IF
CASE 11
LET move_row=no_more_moves
EXIT SUB
END SELECT
LET move_row = row + IncRow
LET move_column = column + IncCol
IF move_row<1 or move_column<1 or max(move_row,move_column)>8 then LET move_row=0 ; off the board, skip
END SUB
;___________________________________________________________________________________________________
SUB KnightMove(row,column,num,move_row, move_column)
SELECT CASE num
CASE 1
LET move_row= row -2
LET move_column=column -1
CASE 2
LET move_row= row -2
LET move_column=column +1
CASE 3
LET move_row= row -1
LET move_column=column -2
CASE 4
LET move_row= row -1
LET move_column=column +2
CASE 5
LET move_row= row +1
LET move_column=column -2
CASE 6
LET move_row= row +1
LET move_column=column +2
CASE 7
LET move_row= row +2
LET move_column=column -1
CASE 8
LET move_row= row +2
LET move_column=column +1
CASE Else
LET move_row=no_more_moves
EXIT SUB
END SELECT
; move is outside the board, then move_row = 0 (invalid move)
IF move_row<1 or move_column<1 or max(move_row,move_column)>8 then LET move_row=0
END SUB
;___________________________________________________________________________________________________
SUB RookMove(row,column,num,move_row, move_column, board(,),CastleFlag)
LOCAL IncRow,IncCol ; Direction to move in (-1 or 0 or 1)
LOCAL NumSquares ; Number of squares to move
LET NumSquares = num - int(num/10)*10 ; first digit of num is direction of move, second tells how far
SELECT CASE int(num/10)
CASE 0
LET IncRow = +1
CASE 1
LET IncRow = -1
CASE 2
LET IncCol = +1
CASE 3
LET IncCol = -1
CASE 4
LET move_row=no_more_moves
EXIT SUB
END SELECT
LET move_row = row + IncRow * NumSquares
LET move_column = column + IncCol * NumSquares
IF move_row<1 or move_column<1 or max(move_row,move_column)>8 then
LET move_row=0 ; off the board, skip
LET num=int(num/10)*10+10 ; ... and change direction
ELSEIF board(move_row,move_column)<>0 then
LET num=int(num/10)*10+10 ; piece encountered, so stop looking in current direction
ELSE
END IF
END SUB
;___________________________________________________________________________________________________
SUB BishopMove(row,column,num,move_row, move_column, board(,))
LOCAL IncRow,IncCol ; Direction to move in (-1 or 0 or 1)
LOCAL NumSquares ; Number of squares to move
LET NumSquares = num - int(num/10)*10 ; first digit of num is direction of move, second tells how far
SELECT CASE int(num/10)
CASE 0
LET IncRow = +1
LET IncCol = +1
CASE 1
LET IncRow = -1
LET IncCol = -1
CASE 2
LET IncRow = +1
LET IncCol = -1
CASE 3
LET IncRow = -1
LET IncCol = +1
CASE 4
LET move_row=no_more_moves
EXIT SUB
END SELECT
LET move_row = row + IncRow * NumSquares
LET move_column = column + IncCol * NumSquares
IF move_row<1 or move_column<1 or max(move_row,move_column)>8 then
LET move_row=0 ; off the board, skip
LET num=int(num/10)*10+10 ; ... and change direction
ELSEIF board(move_row,move_column)<>0 then
LET num=int(num/10)*10+10 ; piece encountered, so stop looking in current direction
ELSE
END IF
END SUB
;___________________________________________________________________________________________________
SUB QueenMove(row,column,num,move_row, move_column, board(,))
LOCAL IncRow,IncCol ; Direction to move in (-1 or 0 or 1)
LOCAL NumSquares ; Number of squares to move
LET NumSquares = num - int(num/10)*10 ; first digit of num is direction of move, second tells how far
SELECT CASE int(num/10)
CASE 0
LET IncRow = +1
LET IncCol = +1
CASE 1
LET IncRow = -1
LET IncCol = -1
CASE 2
LET IncRow = +1
LET IncCol = -1
CASE 3
LET IncRow = -1
LET IncCol = +1
CASE 4
LET IncRow = +1
CASE 5
LET IncRow = -1
CASE 6
LET IncCol = +1
CASE 7
LET IncCol = -1
CASE 8
LET move_row=no_more_moves
EXIT SUB
END SELECT
LET move_row = row + IncRow * NumSquares
LET move_column = column + IncCol * NumSquares
IF move_row<1 or move_column<1 or max(move_row,move_column)>8 then
LET move_row=0 ; off the board, skip
LET num=int(num/10)*10+10 ; ... and change direction
ELSEIF board(move_row,move_column)<>0 then
LET num=int(num/10)*10+10 ; piece encountered, so stop looking in current direction
ELSE
END IF
END SUB
;___________________________________________________________________________________________________
SUB setupboard(board(,)) ; just pawns and king for now
LOCAL x
MAT board=zer(1 To 8, 1 To 8)
FOR x =1 To 8
LET board(2,x) = 1 ; White pawn
LET board(7,x) = -1 ; Black pawn
NEXT x
LET board(1,1) = 5 ;w rook
LET board(1,2) = 3 ;w knight
LET board(1,3) = 3.1 ;w bishop
LET board(1,4) = 9 ;w queen
LET board(1,5) = 99 ;w king
LET board(1,6) = 3.1 ;w bishop
LET board(1,7) = 3 ;w knight
LET board(1,8) = 5 ;w rook
LET board(8,1)=-5 ; b rook
LET board(8,2)=-3 ; b knight
LET board(8,3)=-3.1 ; b bishop
LET board(8,4)=-9 ; b queen
LET board(8,5)=-99 ; b king
LET board(8,6)=-3.1 ; b bishop
LET board(8,7)=-3 ; b knight
LET board(8,8)=-5 ; b rook
END SUB
END SUB
;___________________________________________________________________________________________________
SUB printboard(board(,))
LOCAL x,y
CLEAR
SET BACK "black"
FOR x=8 To 1 Step -1
SET COLOR "white"
PRINT x;" ";
FOR y=1 To 8
IF sgn(board(x,y))>0 then
SET COLOR "red"
ELSEIF sgn(board(x,y))<0 then
SET COLOR "yellow"
ELSE
SET COLOR "green"
END IF
SELECT CASE board(x,y)
CASE 0
IF mod(y+x,2)=0 then PRINT " "&chr$(250); else PRINT " "&chr$(249);
CASE 1
PRINT " P";
CASE -1
PRINT " p";
CASE 3
PRINT " N";
CASE -3
PRINT " n";
CASE 3.1
PRINT " B";
CASE -3.1
PRINT " b";
CASE 5
PRINT " R";
CASE -5
PRINT " r";
CASE 9
PRINT " Q";
CASE -9
PRINT " q";
CASE 99
PRINT " K";
CASE -99
PRINT " k";
END SELECT
NEXT y
PRINT
NEXT x
SET COLOR "black"
PRINT ""
PRINT " A B C D E F G H"
END SUB
SUB drawboard(board(,),BoardPic$,BlackSquare$,WhiteSquare$)
LOCAL colstr$,x,y
SET BACK "black"
SET COLOR "white"
CLEAR
LET colstr$="abcdefgh"
IF BoardPic$="" then
FOR x = 1 to 9 ; Board
PLOT x,1;x,9
PLOT 1,x;9,x
NEXT x
FOR y=1 to 8
SET COLOR "cyan"
PLOT TEXT, AT y+.5,.5: colstr$[y:y] ; type letter coordinates
FOR x=1 to 8
SET COLOR "cyan"
PLOT TEXT, AT .5,x+.5: str$(x) ; type number coordinates
IF mod(x+y,2)=0 then
; SET COLOR "brown" ; fill every other square
SET COLOR MIX (20) .3,.3,.3
SET COLOR 20
ELSE
SET COLOR "white" ; fill every other square
END IF
FLOOD x+.5,y+.5
NEXT x
NEXT y
BOX KEEP 0,9,0,9 in BoardPic$
BOX KEEP 1,2,1,2 in BlackSquare$
BOX KEEP 2,3,1,2 in WhiteSquare$
ELSE
BOX SHOW boardpic$ at 0,0
END IF
FOR y=1 to 8
FOR x=1 to 8
SELECT CASE board(x,y)
CASE 0
CASE 1
DRAW WhitePawn with shift(y,x)
CASE -1
DRAW BlackPawn with shift(y,x)
CASE 3
DRAW WhiteKnight with shift(y,x)
CASE -3
DRAW BlackKnight with shift(y,x)
CASE 3.1
DRAW WhiteBishop with shift(y,x)
CASE -3.1
DRAW BlackBishop with shift(y,x)
CASE 5
DRAW WhiteRook with shift(y,x)
CASE -5
DRAW BlackRook with shift(y,x)
CASE 9
DRAW WhiteQueen with shift(y,x)
CASE -9
DRAW BlackQueen with shift(y,x)
CASE 99
DRAW WhiteKing with shift(y,x)
CASE -99
DRAW BlackKing with shift(y,x)
END SELECT
NEXT x
NEXT y
END SUB
;___________________________________________________________________________________________________
PICTURE WhiteRook
SET COLOR "Green"
PLOT .2,.1; .8,.1; .7,.2;
PLOT .7,.25; .7,.3; .7,.8;
PLOT .3,.8; .3,.3; .3,.2; .2,.1
PLOT .42,.8; .42,.74; .45,.74; .45,.8
PLOT .58,.8; .58,.74; .55,.74; .55,.8
SET COLOR "yellow"
FLOOD .5,.5
END PICTURE
PICTURE BlackRook
SET COLOR "Green"
PLOT .2,.1; .8,.1; .7,.2;
PLOT .7,.25; .7,.3; .7,.8;
PLOT .3,.8; .3,.3; .3,.2; .2,.1
PLOT .42,.8; .42,.74; .45,.74; .45,.8
PLOT .58,.8; .58,.74; .55,.74; .55,.8
SET COLOR "Black"
FLOOD .5,.5
END PICTURE
PICTURE WhiteKnight
SET COLOR "Green"
PLOT .2,.1;.8,.1;.8,.2;
PLOT .7,.25;.7,.3;.8,.4;.65,.7;.6,.9;.55,.9;
PLOT .5,.82;.2,.75;.2,.6;.3,.6;.4,.55;
PLOT .25,.45;.2,.37;.3,.3;.3,.25;.2,.2;.2,.1
SET COLOR "yellow"
FLOOD .5,.5
END PICTURE
PICTURE BlackKnight
SET COLOR "Green"
PLOT .2,.1;.8,.1;.8,.2;
PLOT .7,.25;.7,.3;.8,.4;.65,.7;.6,.9;.55,.9;
PLOT .5,.82;.2,.75;.2,.6;.3,.6;.4,.55;
PLOT .25,.45;.2,.37;.3,.3;.3,.25;.2,.2;.2,.1
SET COLOR "Black"
FLOOD .5,.5
END PICTURE
PICTURE WhitePawn
SET COLOR "Green"
PLOT .2,.1; .8,.1; .63,.2;
PLOT .63,.35; .65,.55;
PLOT .60,.57; .55,.60; .45,.60; .40,.57;
PLOT .37,.55;.39,.35; .39,.2; .2,.1
SET COLOR "yellow"
FLOOD .5,.5
END PICTURE
PICTURE Blackpawn
SET COLOR "green"
PLOT .2,.1; .8,.1; .63,.2;
PLOT .63,.35; .65,.55;
PLOT .60,.57; .55,.60; .45,.60; .40,.57;
PLOT .37,.55;.39,.35; .39,.2; .2,.1
SET COLOR "black"
FLOOD .5,.5
END PICTURE
PICTURE WhiteBishop
SET COLOR "Green"
PLOT .2,.1; .8,.1; .63,.2;
PLOT .63,.35; .65,.65;
PLOT .60,.67; .55,.76; .45,.76;.40,.67;
PLOT .37,.65;.39,.35; .39,.2; .2,.1
PLOT .60,.67; .52,.52; .55,.52; .62,.69
SET COLOR "Yellow"
FLOOD .5,.3
END PICTURE
PICTURE BlackBishop
SET COLOR "green"
PLOT .2,.1; .8,.1; .63,.2;
PLOT .63,.35; .65,.65;
PLOT .60,.67; .55,.76; .45,.76;.40,.67;
PLOT .37,.65;.39,.35; .39,.2; .2,.1
SET COLOR "Black"
FLOOD .5,.5
SET COLOR "yellow"
PLOT .60,.67; .52,.52; .55,.52; .62,.69
END PICTURE
PICTURE WhiteKing
SET COLOR "green"
PLOT .2,.1; .8,.1; .61,.55; .55,.60;
PLOT .55,.73;.8,.73;.8,.78;.55,.78;.55,1;
PLOT .45,1;.45,.78;.2,.78; .2,.73; .45,.73; .45,.60;
PLOT .39,.55; .2,.1
SET COLOR "yellow"
FLOOD .53,.77
FLOOD .5,.5
END PICTURE
PICTURE BlackKing
SET COLOR "green"
PLOT .2,.1; .8,.1; .61,.55; .55,.60;
PLOT .55,.73;.8,.73;.8,.78;.55,.78;.55,1;
PLOT .45,1;.45,.78;.2,.78; .2,.73; .45,.73; .45,.60;
PLOT .39,.55; .2,.1
SET COLOR "black"
FLOOD .5,.5
END PICTURE
PICTURE WhiteQueen
SET COLOR "Green"
PLOT .2,.1; .8,.1; .63,.2;
PLOT .8,.8; .66,.66; .5,1; .33,.66; .2,.8;
PLOT .39,.2; .2,.1
SET COLOR "yellow"
FLOOD .5,.5
END PICTURE
PICTURE BlackQueen
SET COLOR "green"
PLOT .2,.1; .8,.1; .63,.2;
PLOT .8,.8; .66,.66; .5,1; .33,.66; .2,.8;
PLOT .39,.2; .2,.1
SET COLOR "black"
FLOOD .5,.5
END PICTURE
;___________________________________________________________________________________________________
SUB MovePics(FromRow,FromCol,ToRow,ToCol,BlackSquare$,WhiteSquare$,piece)
IF mod(FromCol+FromRow,2)=1 then
BOX SHOW WhiteSquare$ at FromCol,FromRow
ELSE
BOX SHOW BlackSquare$ at FromCol,FromRow
END IF
IF mod(ToRow+ToCol,2)=1 then
BOX SHOW WhiteSquare$ at ToCol,ToRow
ELSE
BOX SHOW BlackSquare$ at ToCol,ToRow
END IF
SELECT CASE piece
CASE 0
CASE 1
DRAW WhitePawn with shift(ToCol,ToRow)
CASE -1
DRAW BlackPawn with shift(ToCol,ToRow)
CASE 3
DRAW WhiteKnight with shift(ToCol,ToRow)
CASE -3
DRAW BlackKnight with shift(ToCol,ToRow)
CASE 3.1
DRAW WhiteBishop with shift(ToCol,ToRow)
CASE -3.1
DRAW BlackBishop with shift(ToCol,ToRow)
CASE 5
DRAW WhiteRook with shift(ToCol,ToRow)
CASE -5
DRAW BlackRook with shift(ToCol,ToRow)
CASE 9
DRAW WhiteQueen with shift(ToCol,ToRow)
CASE -9
DRAW BlackQueen with shift(ToCol,ToRow)
CASE 99
DRAW WhiteKing with shift(ToCol,ToRow)
CASE -99
DRAW BlackKing with shift(ToCol,ToRow)
END SELECT
END SUB
;___________________________________________________________________________________________________
SUB SetCastleFlag(x,y,CastleFlag)
LOCAL tmp
SELECT CASE x ; Each castling piece is assigned a prime number flag
CASE 1 ; When a peice is moved, the flags are set by multiplying
SELECT CASE y ; the pieces prime number by the other CastleFlags
CASE 1
LET tmp=2
CASE 5
LET tmp=2*3 ; any king move sets all flags for side
CASE 8
LET tmp=3
CASE else
END SELECT
CASE 8
SELECT CASE y
CASE 1
LET tmp=5
CASE 5
LET tmp=5*7
CASE 8
LET tmp=7
CASE else
END SELECT
CASE else
END SELECT
LET CastleFlag=tmp*CastleFlag
END SUB
;___________________________________________________________________________________________________
FUNCTION AskCastleFlag(x,y,CastleFlag)
LOCAL divisor
SELECT CASE x
CASE 1
SELECT CASE y
CASE 1
LET divisor=2
CASE 5
LET divisor=2*3
CASE 8
LET divisor=3
CASE ELSE
LET divisor=1
END SELECT
CASE 8
SELECT CASE y
CASE 1
LET divisor=5
CASE 5
LET divisor=5*7
CASE 8
LET divisor=7
CASE ELSE
LET divisor=1
END SELECT
END SELECT
; if divisor divides evenly into CastleFlag, then flag was set
IF CastleFlag<>1 and mod(CastleFlag,divisor)=0 then
LET AskCastleFlag=1
ELSE
LET AskCastleFlag=0
END IF
END FUNCTION
;___________________________________________________________________________________________________
SUB info(BestFromR(),BestFromC(),BestToR(),BestToC(),NumberEvaluated,besteval,note$,MaxPlyLevel)
LOCAL MaxRow,MaxCol,colstr$,x
LET colstr$="abcdefgh"
ASK MAX CURSOR MaxRow,MaxCol
SET BACK "black"
SET COLOR "white"
SET CURSOR MaxRow-5,1
PRINT
IF note$<>"" then
PRINT note$
ELSE
FOR x=MaxPlyLevel to 1 step -1
PRINT colstr$[BestFromC(x):BestFromC(x)]&str$(BestFromR(x))&colstr$[BestToC(x):BestToC(x)]&str$(BestToR(x));" ";
NEXT x
END IF
PRINT " "
PRINT "your score = ";
IF abs(besteval)<9999 then PRINT round(besteval*10)/10;" " else PRINT " "
PRINT "Positions Evaluated = ";NumberEvaluated
END SUB
FUNCTION Notate$(FromR,FromC,ToR,ToC)
LOCAL colstr$
LET colstr$="abcdefgh"
LET Notate$=colstr$[FromC:FromC]&trim$(str$(FromR))&colstr$[ToC:ToC]&trim$(str$(ToR))
END FUNCTION
SUB resign
LOCAL x,y,a,b,c
ASK CURSOR x,y
SOUND 1000,0.1
FOR a=1 to 30
SET CURSOR x,y
IF mod(a,2)=0 then SET COLOR "yellow" else SET COLOR "cyan"
PRINT "*** I resign ***"
IF key input then STOP
PAUSE .2
NEXT a
STOP
END SUB
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