用Python创建国际象棋，棋子动作受到Bishop的影响

Question

I am in the progress of making chess using Pygame.

Currently, I only have the ability to make white pawns and white bishops. I have a projected() function for each of the WhitePawn and WhiteBishop classes, which highlights the positions on the board that the pieces can go. For example, if there is a pawn on E2 and a bishop on E4, then E2 (when you click the piece) and E3 would light up, but E4 would not light up because the bishop is in the way. When you click on the lit up square, then it moves the piece to that position on the board. The noProjected() function for both classes is supposed to remove the lit up positions on the board.

My issue right now is that if the white pawn tries to move through a white bishop's projected path (even if I didn't click on it), it doesn't light up the square and therefore I can't move there. For example, if a White Pawn is on E2 and White Bishop on D4, then E2 and E4 light up, when E2, E3, and E4 are supposed to light up.

I do have a guess that the issue is the for loop on the bottom: play.totalPlayList consists of play.whitePawnList (all the white pawns on board) and play.whiteBishopList in that order. When I reversed the order, in that list, the pawn movement worked (but of course the bishop movement didn't). So even if I click on the pawn only, the whiteBishop.noProjected() function still gets called which I don't want.

class PlayWhiteBishop(pygame.sprite.Sprite):
    def __init__(self):
        self.select = 0
    def update(self):
    def highlight(self):
        self.image = images["sprWhiteBishopHighlighted"]
        self.select = 1
    def projected(self):
        for grid in room.gridList:
            for i in range(1,8):
                if ord(grid.coordinate[0]) == ord(self.coordinate[0])-i and grid.coordinate[1] == self.coordinate[1]-i and grid.occupied == 0:
                    grid.highlight()
            for i in range(1,8):
                if ord(grid.coordinate[0]) == ord(self.coordinate[0])-i and grid.coordinate[1] == self.coordinate[1]+i and grid.occupied == 0:
                    grid.highlight()
            for i in range(1,8):
                if ord(grid.coordinate[0]) == ord(self.coordinate[0])+i and grid.coordinate[1] == self.coordinate[1]-i and grid.occupied == 0:
                    grid.highlight()
            for i in range(1,8):
                if ord(grid.coordinate[0]) == ord(self.coordinate[0])+i and grid.coordinate[1] == self.coordinate[1]+i and grid.occupied == 0:
                    grid.highlight()
    def noHighlight(self):
        self.image = images["sprWhiteBishop"]
        self.select = 0
    def noProjected(self):
        #SAME EXACT CODE as projected() except replace grid.highlight() with grid.noHighlight()

while RUNNING:
    elif (event.type == pygame.MOUSEBUTTONDOWN and pygame.mouse.get_pressed()[0]
        for pieceList in play.totalPlayList:
            for piece in pieceList:
                if (piece.rect.collidepoint(mousePos) and piece.select == 0):
                    piece.highlight()
                    piece.projected()
                else:
                    piece.noHighlight()
                    piece.noProjected()

Thanks!

Answer 1

You've pretty much identified the problem yourself: you're calling noProjected() for every piece on the board, regardless of whether or not it's moving -- and that's not the functionality you need there. Instead, you need to wait until the player chooses a piece, and then make the calls to trace the moves for only that piece.

If you're moving the pawn, you have no business processing where the bishop can move; the only problem is whether the bishop itself is in the way. You shouldn't change highlights based on multiple lines of attack.

One note for your eventual game: you do have to pay attention when castling: the king cannot castle out of, into, or through check: if that middle square is under enemy attack, the player can't castle.