In my chess game I created an AI that now can look 3 steps into the future. Each step I update the the variable Moves in chess_piece that contains an array of moves a chess_piece can make.
The problem is, if I update the Moves for Board.Pieces deeper in my algorithm, it also seems to update the NewPieces in the for loop at the beginning of the algorithm. Is there a way so that NewPieces in this for loop does not update if I update the pieces later on in the algorithm?
The entire recursive function for my algorithm
Board.UpdateBoardState(Depth) updates the array Moves for all chess_piece in Board
GenerateAlphaBetaTree(Board:board,Depth:int, Alpha:int, Beta:int)<suspends>:tuple(chess_piece,move,int)={
if(Mod[PositionsChecked,25] = 0):
#Print("positions checked = {PositionsChecked}")
Sleep(0.003)
if(Depth = 0){
set PositionsChecked += 1
Score := EvaluateState(Board,Board.Turn)
if(Board.Turn= color.White):
# Print("awe at root with score {Score} for color white")
else:
# Print("awe at root with score {Score} for color black")
return (chess_piece{},move{},Score)
}
else:
set Nodes += 1
var Alphaa:int = -10000
var Betaa:int = 10000
var X:int = 0
var Best:tuple(chess_piece,move,int) = (chess_piece{},move{},-10000)
var NumPositions:int = 0
if(Board.Turn = AIColor):
set Best = (chess_piece{},move{},-10000)
set X = -10000
else:
set Best = (chess_piece{},move{},10000)
set X = 10000
Board.UpdateBoardState(Depth)
NewPieces:=Board.Pieces
for(Piece:NewPieces):
if(Piece.Color = Board.Turn):
for(Move:Piece.Moves):
set NumPositions += 1
#Print("move {Move.Start} to {Move.Target} total moves for this are {Piece.Moves.Length} wi d {Depth}")
Tuple := SimulateMove(Board,Piece,Move.Target)
MaybeSlainPiece := Tuple(0)
MaybePromotedPiece := Tuple(1)
set Board.Turn = FlipColor(Board.Turn)
Triple := GenerateAlphaBetaTree(Board,Depth-1, Alpha, Beta)
Score := Triple(2)
set Board.Turn = FlipColor(Board.Turn)
if(Board.Turn <> AIColor):
# Print("eval player move {Move.Start} to {Move.Target} with score {Score} , best {Best(2)}")
if(Score <= Best(2)): # if score < +infinite
set Best = (Piece,Move,Score)
else if(Board.Turn = AIColor):
#AI evaulated board, return highest number
#Print("eval ai move {Move.Start} to {Move.Target} with score {Score} , best {Best(2)}")
if(Score >= Best(2)): # if score > -infinite
set Best = (Piece,Move,Score)
#Print("undo move")
UndoMove(Board,Piece,Move,MaybeSlainPiece,MaybePromotedPiece)
if(NumPositions = 0):
#set PositionsChecked += 1
Score := EvaluateState(Board,Board.Turn)
if(Board.Turn= color.White):
#Print("++++we at early root with score {Score} for color white")
else:
#Print("+++++we at early root with score {Score} for color black")
return (chess_piece{},move{},Score)
# Print("----------- Checked {NumPositions} board positions and total positionschecked = {PositionsChecked}")
if(Board.Turn = AIColor):
# Print("AI: best was move{Best(1).Start} to {Best(1).Target} with ID {Best(0).ID} and score {Best(2)} ------")
else:
#Print("Player: best was move to {Best(1).Target} with ID {Best(0).ID} and score {Best(2)} -------")
return Best
}