X-Git-Url: https://git.auder.net/img/rock_paper_scissors_lizard_spock.gif?a=blobdiff_plain;f=public%2Fjavascripts%2Fvariants%2FUltima.js;h=d5b9f88435d6173204e14ed34669e27a0a2d7177;hb=f4fd6580a227a352f6e0e95870954bc2fa2ce97f;hp=c98822dcbf0e85aa68889faf0f4c338194dd79ef;hpb=9d218497ab97bc0e94ec4c1f0a40cf02df3ea0d4;p=vchess.git

diff --git a/public/javascripts/variants/Ultima.js b/public/javascripts/variants/Ultima.js
index c98822dc..d5b9f884 100644
--- a/public/javascripts/variants/Ultima.js
+++ b/public/javascripts/variants/Ultima.js
@@ -50,9 +50,9 @@ class UltimaRules extends ChessRules
 	//  - a "bishop" is a chameleon, capturing as its prey
 	//  - a "queen" is a withdrawer, capturing by moving away from pieces
 
-	getPotentialMovesFrom([x,y])
+	// Is piece on square (x,y) immobilized?
+	isImmobilized([x,y])
 	{
-		// Pre-check: is thing on this square immobilized?
 		const piece = this.getPiece(x,y);
 		const color = this.getColor(x,y);
 		const oppCol = this.getOppCol(color);
@@ -68,7 +68,7 @@ class UltimaRules extends ChessRules
 			{
 				const oppPiece = this.getPiece(i,j);
 				if (oppPiece == V.BISHOP && piece == V.IMMOBILIZER)
-					return [];
+					return true;
 				if (oppPiece == V.IMMOBILIZER && ![V.BISHOP,V.IMMOBILIZER].includes(piece))
 				{
 					// Moving is impossible only if this immobilizer is not neutralized
@@ -78,15 +78,22 @@ class UltimaRules extends ChessRules
 						if (i2>=0 && i2<sizeX && j2>=0 && j2<sizeY
 							&& this.board[i2][j2] != V.EMPTY && this.getColor(i2,j2) == color)
 						{
-							const friendlyPiece = this.getPiece(i2,j2);
-							if ([V.BISHOP,V.IMMOBILIZER].includes(friendlyPiece))
-								break outerLoop;
+							if ([V.BISHOP,V.IMMOBILIZER].includes(this.getPiece(i2,j2)))
+								return false;
 						}
 					}
-					return []; //immobilizer isn't neutralized
+					return true; //immobilizer isn't neutralized
 				}
 			}
 		}
+		return false;
+	}
+
+	getPotentialMovesFrom([x,y])
+	{
+		// Pre-check: is thing on this square immobilized?
+		if (this.isImmobilized([x,y]))
+			return [];
 		switch (this.getPiece(x,y))
 		{
 			case VariantRules.IMMOBILIZER:
@@ -288,13 +295,10 @@ class UltimaRules extends ChessRules
 	{
 		let moves = super.getPotentialQueenMoves([x,y])
 			.concat(this.getKnightCaptures([x,y],"asChameleon"));
+		// No "king capture" because king cannot remain under check
 		this.addPawnCaptures(moves, "asChameleon");
 		this.addRookCaptures(moves, "asChameleon");
 		this.addQueenCaptures(moves, "asChameleon");
-		// Add king capture if it's within range
-		const oppKp = this.kingPos[this.getOppCol(this.turn)];
-		if (Math.abs(x-oppKp[0]) <= 1 && Math.abs(y-oppKp[1]) <= 1)
-			moves.push(this.getBasicMove([x,y],oppKp));
 		// Post-processing: merge similar moves, concatenating vanish arrays
 		let mergedMoves = {};
 		const [sizeX,sizeY] = VariantRules.size;
@@ -376,77 +380,176 @@ class UltimaRules extends ChessRules
 			V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
 	}
 
-	atLeastOneMove()
-	{
-		if (this.kingPos[this.turn][0] < 0)
-			return false;
-		return super.atLeastOneMove();
-	}
+	// isAttacked() is OK because the immobilizer doesn't take
 
-	underCheck(move)
+	isAttackedByPawn([x,y], colors)
 	{
-		return false; //there is no check
+		// Square (x,y) must be surroundable by two enemy pieces,
+		// and one of them at least should be a pawn (moving).
+		const dirs = [ [1,0],[0,1],[1,1],[-1,1] ];
+		const steps = VariantRules.steps[VariantRules.ROOK]
+			.concat(VariantRules.steps[VariantRules.BISHOP]);
+		const [sizeX,sizeY] = VariantRules.size;
+		for (let dir of dirs)
+		{
+			const [i1,j1] = [x-dir[0],y-dir[1]]; //"before"
+			const [i2,j2] = [x+dir[0],y+dir[1]]; //"after"
+			if (i1>=0 && i1<sizeX && i2>=0 && i2<sizeX
+				&& j1>=0 && j1<sizeY && j2>=0 && j2<sizeY)
+			{
+				if ((this.board[i1][j1]!=VariantRules.EMPTY
+					&& colors.includes(this.getColor(i1,j1))
+					&& this.board[i2][j2]==VariantRules.EMPTY)
+						||
+					(this.board[i2][j2]!=VariantRules.EMPTY
+					&& colors.includes(this.getColor(i2,j2))
+					&& this.board[i1][j1]==VariantRules.EMPTY))
+				{
+					// Search a movable enemy pawn landing on the empty square
+					for (let step of steps)
+					{
+						let [ii,jj] = (this.board[i1][j1]==VariantRules.EMPTY ? [i1,j1] : [i2,j2]);
+						let [i3,j3] = [ii+step[0],jj+step[1]];
+						while (i3>=0 && i3<sizeX && j3>=0 && j3<sizeY
+							&& this.board[i3][j3]==VariantRules.EMPTY)
+						{
+							i3 += step[0];
+							j3 += step[1];
+						}
+						if (i3>=0 && i3<sizeX && j3>=0 && j3<sizeY
+							&& this.getPiece(i3,j3) == VariantRules.PAWN
+							&& !this.isImmobilized([i3,j3]))
+						{
+							return true;
+						}
+					}
+				}
+			}
+		}
+		return false;
 	}
 
-	getCheckSquares(move)
+	isAttackedByRook([x,y], colors)
 	{
-		const c = this.getOppCol(this.turn); //opponent
-		const saveKingPos = this.kingPos[c]; //king might be taken
-		this.play(move);
-		// The only way to be "under check" is to have lost the king (thus game over)
-		let res = this.kingPos[c][0] < 0
-			? [ JSON.parse(JSON.stringify(saveKingPos)) ]
-			: [ ];
-		this.undo(move);
-		return res;
+		// King must be on same column or row,
+		// and a rook should be able to reach a capturing square
+		const [sizeX,sizeY] = VariantRules.size;
+		// colors contains only one element, giving the oppCol and thus king position
+		const sameRow = (x == this.kingPos[colors[0]][0]);
+		const sameColumn = (y == this.kingPos[colors[0]][1]);
+		if (sameRow || sameColumn)
+		{
+			// Look for the enemy rook (maximum 1)
+			for (let i=0; i<sizeX; i++)
+			{
+				for (let j=0; j<sizeY; j++)
+				{
+					if (this.board[i][j] != VariantRules.EMPTY
+						&& this.getPiece(i,j) == VariantRules.ROOK)
+					{
+						if (this.isImmobilized([i,j]))
+							return false; //because only one rook
+						// Can it reach a capturing square?
+						// Easy but quite suboptimal way (TODO): generate all moves (turn is OK)
+						const moves = this.getPotentialMovesFrom([i,j]);
+						for (let move of moves)
+						{
+							if (sameRow && move.end.y == y || sameColumn && move.end.x == x)
+								return true;
+						}
+					}
+				}
+			}
+		}
+		return false;
 	}
 
-	updateVariables(move)
+	isAttackedByKnight([x,y], colors)
 	{
-		// Just update king(s) position(s)
-		const piece = this.getPiece(move.start.x,move.start.y);
-		const c = this.getColor(move.start.x,move.start.y);
-		if (piece == VariantRules.KING && move.appear.length > 0)
+		// Square (x,y) must be on same line as a knight,
+		// and there must be empty square(s) behind.
+		const V = VariantRules;
+		const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+		const [sizeX,sizeY] = V.size;
+		outerLoop:
+		for (let step of steps)
 		{
-			this.kingPos[c][0] = move.appear[0].x;
-			this.kingPos[c][1] = move.appear[0].y;
+			const [i0,j0] = [x+step[0],y+step[1]];
+			if (i0>=0 && i0<sizeX && j0>=0 && j0<sizeY && this.board[i0][j0] == V.EMPTY)
+			{
+				// Try in opposite direction:
+				let [i,j] = [x-step[0],y-step[1]];
+				while (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j] == V.EMPTY)
+				{
+					i -= step[0];
+					j -= step[1];
+				}
+				if (i>=0 && i<sizeX && j>=0 && j<sizeY && colors.includes(this.getColor(i,j))
+					&& this.getPiece(i,j) == V.KNIGHT)
+				{
+					if (!this.isImmobilized([i,j]))
+						return true;
+				}
+			}
 		}
-		// Does this move takes opponent's king?
-		const oppCol = this.getOppCol(c);
-		for (let i=1; i<move.vanish.length; i++)
+		return false;
+	}
+
+	isAttackedByBishop([x,y], colors)
+	{
+		// We cheat a little here: since this function is used exclusively for king,
+		// it's enough to check the immediate surrounding of the square.
+		const V = VariantRules;
+		const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+		const [sizeX,sizeY] = V.size;
+		for (let step of adjacentSteps)
 		{
-			if (move.vanish[i].p == VariantRules.KING)
+			const [i,j] = [x+step[0],y+step[1]];
+			if (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j]!=V.EMPTY
+				&& colors.includes(this.getColor(i,j)) && this.getPiece(i,j) == V.BISHOP)
 			{
-				this.kingPos[oppCol] = [-1,-1];
-				break;
+				return true; //bishops are never immobilized
 			}
 		}
+		return false;
 	}
 
-	unupdateVariables(move)
+	isAttackedByQueen([x,y], colors)
 	{
-		super.unupdateVariables(move);
-		const c = this.getColor(move.start.x,move.start.y);
-		const oppCol = this.getOppCol(c);
-		if (this.kingPos[oppCol][0] < 0)
+		// Square (x,y) must be adjacent to a queen, and the queen must have
+		// some free space in the opposite direction from (x,y)
+		const V = VariantRules;
+		const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+		const [sizeX,sizeY] = V.size;
+		for (let step of adjacentSteps)
 		{
-			// Last move took opponent's king
-			for (let i=1; i<move.vanish.length; i++)
+			const sq2 = [x+2*step[0],y+2*step[1]];
+			if (sq2[0]>=0 && sq2[0]<sizeX && sq2[1]>=0 && sq2[1]<sizeY
+				&& this.board[sq2[0]][sq2[1]] == V.EMPTY)
 			{
-				const psq = move.vanish[i];
-				if (psq.p == 'k')
+				const sq1 = [x+step[0],y+step[1]];
+				if (this.board[sq1[0]][sq1[1]] != V.EMPTY
+					&& colors.includes(this.getColor(sq1[0],sq1[1]))
+					&& this.getPiece(sq1[0],sq1[1]) == V.QUEEN
+					&& !this.isImmobilized(sq1))
 				{
-					this.kingPos[oppCol] = [psq.x, psq.y];
-					break;
+					return true;
 				}
 			}
 		}
+		return false;
 	}
 
-	checkGameEnd()
+	updateVariables(move)
 	{
-		// Stalemate, or our king disappeared
-		return this.turn == "w" ? "0-1" : "1-0";
+		// Just update king(s) position(s)
+		const piece = this.getPiece(move.start.x,move.start.y);
+		const c = this.getColor(move.start.x,move.start.y);
+		if (piece == VariantRules.KING && move.appear.length > 0)
+		{
+			this.kingPos[c][0] = move.appear[0].x;
+			this.kingPos[c][1] = move.appear[0].y;
+		}
 	}
 
 	static get VALUES() { //TODO: totally experimental!
@@ -463,10 +566,6 @@ class UltimaRules extends ChessRules
 
 	static get SEARCH_DEPTH() { return 2; } //TODO?
 
-	static get THRESHOLD_MATE() {
-		return 500; //checkmates evals may be slightly below 1000
-	}
-
 	static GenRandInitFen()
 	{
 		let pieces = { "w": new Array(8), "b": new Array(8) };