X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=public%2Fjavascripts%2Fvariants%2FBerolina.js;fp=public%2Fjavascripts%2Fvariants%2FBerolina.js;h=c556f51758c6a8122f1c4818cd363a352097049c;hb=375ecdd1387e729f85ed114e82253469e4849869;hp=0000000000000000000000000000000000000000;hpb=e081ffe361b06ca74db0a36bf72dd73602abf57b;p=vchess.git

diff --git a/public/javascripts/variants/Berolina.js b/public/javascripts/variants/Berolina.js
new file mode 100644
index 00000000..c556f517
--- /dev/null
+++ b/public/javascripts/variants/Berolina.js
@@ -0,0 +1,93 @@
+class BerolinaRules extends ChessRules
+{
+	// En-passant after 2-sq jump
+	getEpSquare(moveOrSquare)
+	{
+		if (!moveOrSquare)
+			return undefined;
+		if (typeof moveOrSquare === "string")
+		{
+			const square = moveOrSquare;
+			if (square == "-")
+				return undefined;
+			return V.SquareToCoords(square);
+		}
+		// Argument is a move:
+		const move = moveOrSquare;
+		const [sx,ex,sy] = [move.start.x,move.end.x,move.start.y];
+		if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) == 2)
+		{
+			return {
+				x: ex,
+				y: (move.end.y + sy)/2
+			};
+		}
+		return undefined; //default
+	}
+
+	// Special pawn rules: promotions to captured friendly pieces,
+	// optional on ranks 8-9 and mandatory on rank 10.
+	getPotentialPawnMoves([x,y])
+	{
+		const color = this.turn;
+		let moves = [];
+		const [sizeX,sizeY] = [V.size.x,V.size.y];
+		const shiftX = (color == "w" ? -1 : 1);
+		const firstRank = (color == 'w' ? sizeX-1 : 0);
+		const startRank = (color == "w" ? sizeX-2 : 1);
+		const lastRank = (color == "w" ? 0 : sizeX-1);
+
+		if (x+shiftX >= 0 && x+shiftX < sizeX) //TODO: always true
+		{
+			const finalPieces = x + shiftX == lastRank
+				? [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]
+				: [V.PAWN]
+			// One square diagonally
+			for (let shiftY of [-1,1])
+			{
+				if (this.board[x+shiftX][y+shiftY] == V.EMPTY)
+				{
+					for (let piece of finalPieces)
+					{
+						moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
+							{c:pawnColor,p:piece}));
+					}
+					if (x == startRank && this.board[x+2*shiftX][y] == V.EMPTY)
+					{
+						// Two squares jump
+						moves.push(this.getBasicMove([x,y], [x+2*shiftX,y+2*shiftY]);
+					}
+				}
+			}
+			// Capture
+			if (this.board[x+shiftX][y] != V.EMPTY
+				&& this.canTake([x,y], [x+shiftX,y]))
+			{
+				for (let piece of finalPieces)
+				{
+					moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
+						{c:pawnColor,p:piece}));
+				}
+			}
+		}
+
+		// En passant
+		const Lep = this.epSquares.length;
+		const epSquare = this.epSquares[Lep-1]; //always at least one element
+		if (!!epSquare && epSquare.x == x+shiftX && epSquare.y == y)
+		{
+			let enpassantMove = this.getBasicMove([x,y], [x+shift,y]);
+			enpassantMove.vanish.push({
+				x: epSquare.x,
+				y: y,
+				p: 'p',
+				c: this.getColor(epSquare.x,y)
+			});
+			moves.push(enpassantMove);
+		}
+
+		return moves;
+	}
+}
+
+const VariantRules = BerolinaRules;