X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=public%2Fjavascripts%2Fbase_rules.js;h=6cab3496b2f9def3bda447e73b7be8b5b94ff6a1;hb=cf1303697774a12ef9bb154014a38797716944cf;hp=d4315c73724b5572437e3e7b3203b12bc7fefda4;hpb=c605216162dfc09cbbe61b0969f8890f28625372;p=vchess.git

diff --git a/public/javascripts/base_rules.js b/public/javascripts/base_rules.js
index d4315c73..6cab3496 100644
--- a/public/javascripts/base_rules.js
+++ b/public/javascripts/base_rules.js
@@ -284,7 +284,7 @@ class ChessRules
 				i += step[0];
 				j += step[1];
 			}
-			if (i>=0 && i<8 && j>=0 && j<8 && this.canTake([x,y], [i,j]))
+			if (i>=0 && i<sizeX && j>=0 && j<sizeY && this.canTake([x,y], [i,j]))
 				moves.push(this.getBasicMove([x,y], [i,j]));
 		}
 		return moves;
@@ -298,9 +298,9 @@ class ChessRules
 		const V = VariantRules;
 		const [sizeX,sizeY] = VariantRules.size;
 		const shift = (color == "w" ? -1 : 1);
-		const firstRank = (color == 'w' ? sizeY-1 : 0);
-		const startRank = (color == "w" ? sizeY-2 : 1);
-		const lastRank = (color == "w" ? 0 : sizeY-1);
+		const firstRank = (color == 'w' ? sizeX-1 : 0);
+		const startRank = (color == "w" ? sizeX-2 : 1);
+		const lastRank = (color == "w" ? 0 : sizeX-1);
 
 		if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank)
 		{
@@ -417,7 +417,7 @@ class ChessRules
 			let step = finalSquares[castleSide][0] < y ? -1 : 1;
 			for (i=y; i!=finalSquares[castleSide][0]; i+=step)
 			{
-				if (this.isAttacked([x,i], oppCol) || (this.board[x][i] != V.EMPTY &&
+				if (this.isAttacked([x,i], [oppCol]) || (this.board[x][i] != V.EMPTY &&
 					// NOTE: next check is enough, because of chessboard constraints
 					(this.getColor(x,i) != c || ![V.KING,V.ROOK].includes(this.getPiece(x,i)))))
 				{
@@ -547,14 +547,15 @@ class ChessRules
 	// Is square x,y attacked by pawns of color c ?
 	isAttackedByPawn([x,y], colors)
 	{
+		const [sizeX,sizeY] = VariantRules.size;
 		for (let c of colors)
 		{
 			let pawnShift = (c=="w" ? 1 : -1);
-			if (x+pawnShift>=0 && x+pawnShift<8)
+			if (x+pawnShift>=0 && x+pawnShift<sizeX)
 			{
 				for (let i of [-1,1])
 				{
-					if (y+i>=0 && y+i<8 && this.getPiece(x+pawnShift,y+i)==VariantRules.PAWN
+					if (y+i>=0 && y+i<sizeY && this.getPiece(x+pawnShift,y+i)==VariantRules.PAWN
 						&& this.getColor(x+pawnShift,y+i)==c)
 					{
 						return true;
@@ -605,16 +606,18 @@ class ChessRules
 	// Generic method for non-pawn pieces ("sliding or jumping"): is x,y attacked by piece != color ?
 	isAttackedBySlideNJump([x,y], colors, piece, steps, oneStep)
 	{
+		const [sizeX,sizeY] = VariantRules.size;
 		for (let step of steps)
 		{
 			let rx = x+step[0], ry = y+step[1];
-			while (rx>=0 && rx<8 && ry>=0 && ry<8 && this.board[rx][ry] == VariantRules.EMPTY
-				&& !oneStep)
+			while (rx>=0 && rx<sizeX && ry>=0 && ry<sizeY
+				&& this.board[rx][ry] == VariantRules.EMPTY && !oneStep)
 			{
 				rx += step[0];
 				ry += step[1];
 			}
-			if (rx>=0 && rx<8 && ry>=0 && ry<8 && this.board[rx][ry] != VariantRules.EMPTY
+			if (rx>=0 && rx<sizeX && ry>=0 && ry<sizeY
+				&& this.board[rx][ry] != VariantRules.EMPTY
 				&& this.getPiece(rx,ry) == piece && colors.includes(this.getColor(rx,ry)))
 			{
 				return true;
@@ -628,7 +631,7 @@ class ChessRules
 	{
 		const color = this.turn;
 		this.play(move);
-		let res = this.isAttacked(this.kingPos[color], this.getOppCol(color));
+		let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)]);
 		this.undo(move);
 		return res;
 	}
@@ -638,7 +641,7 @@ class ChessRules
 	{
 		this.play(move);
 		const color = this.turn; //opponent
-		let res = this.isAttacked(this.kingPos[color], this.getOppCol(color))
+		let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
 			? [ JSON.parse(JSON.stringify(this.kingPos[color])) ] //need to duplicate!
 			: [ ];
 		this.undo(move);
@@ -770,7 +773,7 @@ class ChessRules
 	{
 		const color = this.turn;
 		// No valid move: stalemate or checkmate?
-		if (!this.isAttacked(this.kingPos[color], this.getOppCol(color)))
+		if (!this.isAttacked(this.kingPos[color], [this.getOppCol(color)]))
 			return "1/2";
 		// OK, checkmate
 		return color == "w" ? "0-1" : "1-0";
@@ -800,9 +803,14 @@ class ChessRules
 		return VariantRules.INFINITY;
 	}
 
+	static get SEARCH_DEPTH() {
+		return 3; //2 for high branching factor, 4 for small (Loser chess)
+	}
+
 	// Assumption: at least one legal move
 	getComputerMove(moves1) //moves1 might be precomputed (Magnetic chess)
 	{
+		this.shouldReturn = false;
 		const maxeval = VariantRules.INFINITY;
 		const color = this.turn;
 		if (!moves1)
@@ -834,21 +842,32 @@ class ChessRules
 		}
 		moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
 
+		let candidates = [0]; //indices of candidates moves
+		for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
+			candidates.push(j);
+		let currentBest = moves1[_.sample(candidates, 1)];
+
 		// Skip depth 3 if we found a checkmate (or if we are checkmated in 1...)
-		if (Math.abs(moves1[0].eval) < VariantRules.THRESHOLD_MATE)
+		if (VariantRules.SEARCH_DEPTH >= 3
+			&& Math.abs(moves1[0].eval) < VariantRules.THRESHOLD_MATE)
 		{
 			// TODO: show current analyzed move for depth 3, allow stopping eval (return moves1[0])
 			for (let i=0; i<moves1.length; i++)
 			{
+				if (this.shouldReturn)
+					return currentBest; //depth-2, minimum
 				this.play(moves1[i]);
 				// 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
-				moves1[i].eval = 0.1*moves1[i].eval + this.alphabeta(2, -maxeval, maxeval);
+				moves1[i].eval = 0.1*moves1[i].eval +
+					this.alphabeta(VariantRules.SEARCH_DEPTH-1, -maxeval, maxeval);
 				this.undo(moves1[i]);
 			}
 			moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
 		}
+		else
+			return currentBest;
 
-		let candidates = [0]; //indices of candidates moves
+		candidates = [0];
 		for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
 			candidates.push(j);
 //		console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));