X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=client%2Fsrc%2Fbase_rules.js;h=924f737426ab174eb999f4b9655fe960524bfc35;hb=89021f181ac0689bbc785ce0ebd9a910e66352b0;hp=cc8292c482f70f61c04255063f51b10b16cc168c;hpb=0e16cb26f6380f57f1079ece9bdb654243073bde;p=vchess.git

diff --git a/client/src/base_rules.js b/client/src/base_rules.js
index cc8292c4..924f7374 100644
--- a/client/src/base_rules.js
+++ b/client/src/base_rules.js
@@ -59,7 +59,7 @@ export const ChessRules = class ChessRules
     return (f.charCodeAt()<=90 ? "w"+f.toLowerCase() : "b"+f);
   }
 
-  // Check if FEN describe a position
+  // Check if FEN describe a board situation correctly
   static IsGoodFen(fen)
   {
     const fenParsed = V.ParseFen(fen);
@@ -748,10 +748,11 @@ export const ChessRules = class ChessRules
         continue;
       // If this code is reached, rooks and king are on initial position
 
-      // Nothing on the path of the king ?
-      // (And no checks; OK also if y==finalSquare)
-      let step = finalSquares[castleSide][0] < y ? -1 : 1;
-      for (i=y; i!=finalSquares[castleSide][0]; i+=step)
+      // Nothing on the path of the king ? (and no checks)
+      const finDist = finalSquares[castleSide][0] - y;
+      let step = finDist / Math.max(1, Math.abs(finDist));
+      i = y;
+      do
       {
         if (this.isAttacked([x,i], [oppCol]) || (this.board[x][i] != V.EMPTY &&
           // NOTE: next check is enough, because of chessboard constraints
@@ -760,10 +761,12 @@ export const ChessRules = class ChessRules
         {
           continue castlingCheck;
         }
+        i += step;
       }
+      while (i!=finalSquares[castleSide][0]);
 
       // Nothing on the path to the rook?
-      step = castleSide == 0 ? -1 : 1;
+      step = (castleSide == 0 ? -1 : 1);
       for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step)
       {
         if (this.board[x][i] != V.EMPTY)