Fix e.p. capture

[xboard.git] / backend.c

diff --git a/backend.c b/backend.c
index 3e432ae..552935e 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -7501,6 +7501,7 @@ LeftClick (ClickType clickType, int xPix, int yPix)
        toP = boards[currentMove][y][x];
        frc = appData.fischerCastling || gameInfo.variant == VariantSChess;
        if( (killX < 0 || x != fromX || y != fromY) && // [HGM] lion: do not interpret igui as deselect!
+           legal[y][x] == 0 && // if engine told we can move to here, do it even if own piece
           ((WhitePawn <= fromP && fromP <= WhiteKing &&
             WhitePawn <= toP && toP <= WhiteKing &&
             !(fromP == WhiteKing && toP == WhiteRook && frc) &&
@@ -9889,14 +9890,14 @@ ParseGameHistory (char *game)
 void
 ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
 {
-  ChessSquare captured = board[toY][toX], piece, king; int p, rookX, oldEP = EP_NONE, berolina = 0;
+  ChessSquare captured = board[toY][toX], piece, pawn, king, killed; int p, rookX, oldEP, epRank, berolina = 0;
   int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
 
     /* [HGM] compute & store e.p. status and castling rights for new position */
     /* we can always do that 'in place', now pointers to these rights are passed to ApplyMove */
 
       if(gameInfo.variant == VariantBerolina) berolina = EP_BEROLIN_A;
-      oldEP = (signed char)board[EP_STATUS];
+      oldEP = (signed char)board[EP_FILE]; epRank = board[EP_RANK];
       board[EP_STATUS] = EP_NONE;
       board[EP_FILE] = board[EP_RANK] = 100;
 
@@ -9913,6 +9914,7 @@ ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
 
       if( killX >= 0 && killY >= 0 ) // [HGM] lion: Lion trampled over something
 //           victim = board[killY][killX],
+           killed = board[killY][killX],
            board[killY][killX] = EmptySquare,
            board[EP_STATUS] = EP_CAPTURE;
 
@@ -9925,14 +9927,14 @@ ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
            }
       }
 
-      piece = board[fromY][fromX];
-      if( piece == WhiteLance || piece == BlackLance ) {
+      pawn = board[fromY][fromX];
+      if( pawn == WhiteLance || pawn == BlackLance ) {
            if( gameInfo.variant != VariantSuper && gameInfo.variant != VariantChu ) {
                if(gameInfo.variant == VariantSpartan) board[EP_STATUS] = EP_PAWN_MOVE; // in Spartan no e.p. rights must be set
-               else piece += WhiteLance - WhitePawn; // Lance is Pawn-like in most variants, so let Pawn code treat it by this kludge
+               else pawn += WhitePawn - WhiteLance; // Lance is Pawn-like in most variants, so let Pawn code treat it by this kludge
            }
       }
-      if( piece == WhitePawn ) {
+      if( pawn == WhitePawn ) {
            if(fromY != toY) // [HGM] Xiangqi sideway Pawn moves should not count as 50-move breakers
               board[EP_STATUS] = EP_PAWN_MOVE;
            if( toY-fromY>=2) {
@@ -9945,7 +9947,7 @@ ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
                      board[EP_STATUS] = toX;
           }
       } else
-      if( piece == BlackPawn ) {
+      if( pawn == BlackPawn ) {
            if(fromY != toY) // [HGM] Xiangqi sideway Pawn moves should not count as 50-move breakers
               board[EP_STATUS] = EP_PAWN_MOVE;
            if( toY-fromY<= -2) {
@@ -9984,6 +9986,12 @@ ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
      if(gameInfo.variant == VariantKnightmate)
          king += (int) WhiteUnicorn - (int) WhiteKing;
 
+    if(piece != WhiteKing && piece != BlackKing && pieceDesc[piece] && killX >= 0 && strchr(pieceDesc[piece], 'O') // Betza castling-enabled
+       && (piece < BlackPawn ? killed < BlackPawn : killed >= BlackPawn)) {    // and captures own
+       board[toY][toX] = piece; board[fromY][fromX] = EmptySquare;
+       board[toY][toX + (killX < fromX ? 1 : -1)] = killed;
+        board[EP_STATUS] = EP_NONE; // capture was fake!
+    } else
     /* Code added by Tord: */
     /* FRC castling assumed when king captures friendly rook. [HGM] or RxK for S-Chess */
     if (board[fromY][fromX] == WhiteKing && board[toY][toX] == WhiteRook ||
@@ -10038,11 +10046,11 @@ ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
               && (toX != fromX)
                && gameInfo.variant != VariantXiangqi
                && gameInfo.variant != VariantBerolina
-              && (board[fromY][fromX] == WhitePawn)
+              && (pawn == WhitePawn)
               && (board[toY][toX] == EmptySquare)) {
        board[fromY][fromX] = EmptySquare;
-       board[toY][toX] = WhitePawn;
-       if(toY == board[EP_RANK] - 128 + 1)
+       board[toY][toX] = piece;
+       if(toY == epRank - 128 + 1)
            captured = board[toY - 2][toX], board[toY - 2][toX] = EmptySquare;
        else
            captured = board[toY - 1][toX], board[toY - 1][toX] = EmptySquare;
@@ -10103,11 +10111,11 @@ ApplyMove (int fromX, int fromY, int toX, int toY, int promoChar, Board board)
               && (toX != fromX)
                && gameInfo.variant != VariantXiangqi
                && gameInfo.variant != VariantBerolina
-              && (board[fromY][fromX] == BlackPawn)
+              && (pawn == BlackPawn)
               && (board[toY][toX] == EmptySquare)) {
        board[fromY][fromX] = EmptySquare;
-       board[toY][toX] = BlackPawn;
-       if(toY == board[EP_RANK] - 128 - 1)
+       board[toY][toX] = piece;
+       if(toY == epRank - 128 - 1)
            captured = board[toY + 2][toX], board[toY + 2][toX] = EmptySquare;
        else
            captured = board[toY + 1][toX], board[toY + 1][toX] = EmptySquare;