About to finish completed Ultima rules

diff --git a/TODO b/TODO
index b356853..bb4d6e1 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,5 +1 @@
 Full detection of repeated positions (including turn)
 Full detection of repeated positions (including turn)

-In UltimaChess, consider these rules modifications: http://www.inference.org.uk/mackay/ultima/ultima.html
-Reintroduce isAttackedBy in Ultima, and fix it for pawns --> underCheck + stalemate
---> take into account that an immobilized piece does not give check.
-(chameleons cannot be immobilized)

diff --git a/public/javascripts/variants/Ultima.js b/public/javascripts/variants/Ultima.js
index c98822d..57f3e25 100644 (file)
--- a/public/javascripts/variants/Ultima.js
+++ b/public/javascripts/variants/Ultima.js
@@ -50,9 +50,39 @@ class UltimaRules extends ChessRules
        //  - a "bishop" is a chameleon, capturing as its prey
        //  - a "queen" is a withdrawer, capturing by moving away from pieces
 
        //  - 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?
+                                       // Final check: is this knight immobilized?
+                                       let foundImmobilizer = false;
+                                       let neutralized = false;
+                                       outerLoop:
+                                       for (let step of steps)
+                                       {
+                                               const [i2,j2] = [i+step[0],j+step[1]];
+                                               if (i2>=0 && i2<sizeX && j2>=0 && j2<sizeY
+                                                       && this.board[i2][j2] != V.EMPTY
+                                                       && this.getColor(i2,j2) == oppCol
+                                                       && this.getPiece(i2,j2) == V.IMMOBILIZER)
+                                               {
+                                                       foundImmobilizer = true;
+                                                       // Moving is possible only if this immobilizer is neutralized
+                                                       for (let step2 of steps)
+                                                       {
+                                                               const [i3,j3] = [i2+step2[0],j2+step2[1]];
+                                                               if (i3>=0 && i3<sizeX && j3>=0 && j3<sizeY
+                                                                       && this.board[i3][j3] != V.EMPTY && this.getColor(i3,j3) == color
+                                                                       && [V.BISHOP,V.IMMOBILIZER].includes(this.getPiece(i3,j3)))
+                                                               {
+                                                                       neutralized = true;
+                                                                       break outerLoop;
+                                                               }
+                                                       }
+                                               }
+                                       }
+                                       if (!foundImmobilizer || neutralized)
+                                               return false;
+               

                const piece = this.getPiece(x,y);
                const color = this.getColor(x,y);
                const oppCol = this.getOppCol(color);
                const piece = this.getPiece(x,y);
                const color = this.getColor(x,y);
                const oppCol = this.getOppCol(color);


@@ -87,6 +117,13 @@ class UltimaRules extends ChessRules
                                }
                        }
                }
                                }
                        }
                }

+       }
+
+       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:
                switch (this.getPiece(x,y))
                {
                        case VariantRules.IMMOBILIZER:


@@ -288,13 +325,10 @@ class UltimaRules extends ChessRules
        {
                let moves = super.getPotentialQueenMoves([x,y])
                        .concat(this.getKnightCaptures([x,y],"asChameleon"));
        {
                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");
                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;
                // Post-processing: merge similar moves, concatenating vanish arrays
                let mergedMoves = {};
                const [sizeX,sizeY] = VariantRules.size;


@@ -376,77 +410,153 @@ class UltimaRules extends ChessRules
                        V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
        }
 
                        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)
+       // TODO: check if any pawn can reach capturing square + !immobilized
+       isAttackedByPawn([x,y], colors)

        {
        {

-               return false; //there is no check
+               // Square (x,y) must be surrounded by two enemy pieces,
+               // and one of them at least should be a pawn.
+               const dirs = [ [1,0],[0,1],[1,1],[-1,1] ];
+               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
+                               && this.board[i1][j1]!=VariantRules.EMPTY
+                               && this.board[i2][j2]!=VariantRules.EMPTY
+                               && colors.includes(this.getColor(i1,j1))
+                               && colors.includes(this.getColor(i2,j2))
+                               && [this.getPiece(i1,j1),this.getPiece(i2,j2)].includes(VariantRules.PAWN))
+                       {
+                               return true;
+                       }
+               }
+               return false;

        }
 
        }
 

-       getCheckSquares(move)
+       // TODO: check if enemy's rook can reach capturing squares + !immobilized
+       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;
+               const [sizeX,sizeY] = VariantRules.size;
+               // King must be on same column and a rook on same row (or reverse)
+               if (x == this.kingPos[colors[0]][0]) //using colors[0], only element in this case
+               {
+                       // Look for enemy rook on this column
+                       for (let i=0; i<sizeY; i++)
+                       {
+                               if (this.board[x][i] != VariantRules.EMPTY
+                                       && colors.includes(this.getColor(x,i))
+                                       && this.getPiece(x,i) == VariantRules.ROOK)
+                               {
+                                       return true;
+                               }
+                       }
+               }
+               else if (y == this.kingPos[colors[0]][1])
+               {
+                       // Look for enemy rook on this row
+                       for (let i=0; i<sizeX; i++)
+                       {
+                               if (this.board[i][y] != VariantRules.EMPTY
+                                       && colors.includes(this.getColor(i,y))
+                                       && this.getPiece(i,y) == VariantRules.ROOK)
+                               {
+                                       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!
        }
 
        static get VALUES() { //TODO: totally experimental!


@@ -463,10 +573,6 @@ class UltimaRules extends ChessRules
 
        static get SEARCH_DEPTH() { return 2; } //TODO?
 
 
        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) };
        static GenRandInitFen()
        {
                let pieces = { "w": new Array(8), "b": new Array(8) };

diff --git a/views/rules/Ultima.pug b/views/rules/Ultima.pug
index df8571f..423ba5d 100644 (file)
--- a/views/rules/Ultima.pug
+++ b/views/rules/Ultima.pug
@@ -1,5 +1,5 @@
 p.boxed
 p.boxed

-       | Pieces look the same but behave very differently.
+       | Most pieces look the same but behave very differently.

        | They generally move like an orthodox queen,
        | but capturing rules are complex.
 
        | They generally move like an orthodox queen,
        | but capturing rules are complex.
 


@@ -11,21 +11,20 @@ ul
        li Non-capturing moves: often like queen.
        li Special moves: none.
        li Captures: very special.
        li Non-capturing moves: often like queen.
        li Special moves: none.
        li Captures: very special.

-       li End of game: capture the king.
+       li End of game: standard; see below.

 
 h3 Non-capturing moves
 
 // TODO: short paragraph, only the king moves like an orthodox king
 
 h3 Non-capturing moves
 
 // TODO: short paragraph, only the king moves like an orthodox king

+// Consider these rules modifications: http://www.inference.org.uk/mackay/ultima/ultima.html

 
 h3 Capturing moves
 
 // TODO...
 
 h3 Capturing moves
 
 // TODO...

-// TODO: dire comment suicider une pièce immobilisée (self-capture)

 
 h3 End of the game
 
 // TODO: show the situation from Wikipedia page
 
 h3 End of the game
 
 // TODO: show the situation from Wikipedia page

-// tell that it's much simpler to go until king capture and not very different in this case

 
 h3 Credits
 
 
 h3 Credits