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Corrected bugs from Shape Chess code #361

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Merged
jpneto merged 1 commit into from
May 2, 2026
Merged

Corrected bugs from Shape Chess code #361

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8 changes: 2 additions & 6 deletions locales/en/apgames.json
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Original file line number Diff line number Diff line change
Expand Up @@ -181,7 +181,7 @@
"rootbound": "In Root Bound, two groups of ‘plants’ spread in lifelike ways and vie for control of territory as space for new growth rapidly dwindles.",
"saltire": "Connect your two opposite sides of the board by placing stones and swapping pairs of orthogonally or diagonally adjacent stones. A swap must decrease either the number of crosscuts or the number of supercuts on the board, and it must not increase the number of crosscuts.",
"scaffold": "Scaffold is a drawless connection game played on the intersections of a square grid using stones (as in Go). Black is trying to connect N-S edges of the board, White E-W with an orthogonally connected group. On your turn, place a stone of your color on an empty point. Then, if possible, place a stone of your color on an empty point that is orthogonally adjacent to two groups of your color, and keep making such placements until no more are possible.",
"shapechess": "Shape Chess is a game in which players use their pieces to create line-symmetric shapes. Using three types of actions (drop, jump, and push), players aim to create symmetrical groups of six or more pieces. Try to get four points while successfully blocking your opponent!",
"shapechess": "Shape Chess is a game in which players use their pieces to create line-symmetric shapes. Using three types of actions (placements, jumps, pushes), players aim to create symmetrical groups of six or more pieces, scoring more points for larger groups.",
"sentinel": "A vigil game using a sowing mechanism with stacks. A vigil game is one where some board position must always have line-of-sight to some or all of the player's pieces. In Sentinel, players are required to see the board center at the end of each one of their turns.",
"shifty": "A connection game where you either place a piece orthogonally adjacent to a friendly piece, or move one of your pieces orthogonally adjacent to a friendly piece, by a chess queen's move, to a location not orthogonally adjacent to any other friendly pieces. Crosscuts are illegal. The player that forms an orthogonal or diagonal path connecting their two sides wins.",
"siegeofj": "Place cards, representing armies, to exert pressure on segments of the wall around the city of Jacynth. Exert the most pressure on the most segments to win.",
Expand Down Expand Up @@ -288,6 +288,7 @@
"rincala": "For reasons, the colours are instead red (4 pts), blue (3 pts), green (2 pts), yellow (1 pt). Also, the game terminates as soon as one player earns more than half the points (>=26 pts).",
"rootbound": "The estimated score shows the scores that the board would resolve to if the game were to end in the current board state. Consequently, the first player who forms a partition will briefly appear to have a maximum score. This will correct itself over the course of the game.\n\nThe implementation currently only provides beginner protection for the first move of the game. Be careful not to merge down to one Dead Group.",
"siegeofj": "More information on the Decktet system can be found on the [official Decktet website](https://www.decktet.com). Cards in players' hands are hidden from observers, and they are hidden from opponents until the deck is empty, at which point the players have perfect information, so the hands are revealed.",
"shapechess": "Shape Chess, 形棋 (shape - board game), was designed c.2010 by 日出 (Richu) from Guangzhou, China. The game has evolved into its current form through years of refinement within the Chinese game design community (quoted from Kanare_Abstract). This is not a Chess-like game, but one that uses a very original concept by making players build reflectional symmetric shapes. This implementation includes several board sizes, and also different winning scores, for players who prefer shorter or longer matches.",
"sentinel": "Vigil Games are a class of strategy games in which players must maintain an uninterrupted line of sight between their pieces and a designated reference point or region of the board. The first vigil game on record is 1892's Kastellet.\n\nSentinel is a vigil game where players always need to have at least one line-of-sight to the board's center. Sentinel is the second abstract game of this genre (after more than 130 years!), mixing typical movement and capture ludemes with permanent line-of-sight control of the central square.\n\nThe game mixes forward movement with sowing stacks which are the only way for armies to increase their size.",
"spire": "In this implementation, if you select only one space, it assumes that you placed the ball of your colour, and if you select two spaces, the first space is for the neutral ball and the second space is for the ball of your colour. If the first click is on a space where only one of the neutral ball or the ball of your colour is valid, it will automatically commit that ball.",
"spook": "When using the randomised board setup, the only fairness heuristics that we currently have are that (1) the number of balls in solid 5-ball pyramids of the same colour are equal for both players and (2), the second-highest layer must contain balls of both colours. Feel free to contact us on Discord if you think of other ways to make the game fairer.",
Expand Down Expand Up @@ -2388,11 +2389,6 @@
"name": "Larger 25x25 board"
}
},
"shapechess": {
"#board": {
"name": "12x12 board"
}
},
"sentinel": {
"#board": {
"name": "9x9 board"
Expand Down
141 changes: 92 additions & 49 deletions src/games/shapechess.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -26,17 +26,19 @@ export class ShapeChessGame extends GameBase {
name: "Shape Chess",
uid: "shapechess",
playercounts: [2],
version: "20260430",
dateAdded: "2026-04-30",
version: "20260502",
dateAdded: "2026-05-02",
// i18next.t("apgames:descriptions.shapechess")
description: "apgames:descriptions.shapechess",
notes: "apgames:notes.shapechess",
urls: [
"https://boardgamegeek.com/boardgame/367618",
"https://www.abstractgames.org/shapechess.html",
],
people: [
{
type: "designer",
name: "Richu"
name: "日出 (Richu)"
},
{
type: "coder",
Expand Down Expand Up @@ -73,7 +75,6 @@ export class ShapeChessGame extends GameBase {
public boardSize = 12;
private _points: [number, number][] = []; // if there are points here, the renderer will show them
private _symmetryLine: number[][][] = []; // 1+ captures, each capture is defined by a line [[x0,y0],[x1,y1]]
private _hadCaptures: boolean = false; // true if captures already occurred in this turn
private ruleset: "default" | "5-pts" | "6-pts" | "7-pts" | "8-pts" | "9-pts";

constructor(state?: IShapeChessState | string, variants?: string[]) {
Expand Down Expand Up @@ -165,7 +166,64 @@ export class ShapeChessGame extends GameBase {
}

public moves(): string[] {
return [];
return []; // too many moves
}

// checks if the last action does some captures (relevant to know if player continues playing)
// requires: all actions from 'move' are valid!
private willLastActionCapture(move: string): [boolean, ShapeChessGame] {
const actions: string[] = move.split(','); // we need to process all actions, in sequence
const clone = this.clone(); // the actions will be made in a clone
let hadCaptures = false;

for (let i=0; i<actions.length; i++) {
const action = actions[i]
const moves = action.split("-");

if ( moves.length === 1 ) {
if (! clone.board.has(moves[0]) ) {
clone.board.set(moves[0], clone.currplayer);
} else { // it's a partial push/jump, nothing to do here
break;
}
} else if ( clone.board.get(moves[0])! === clone.currplayer ) { // jump
clone.board.delete(moves[0]);
clone.board.set(moves[1], clone.currplayer);
} else { // push
clone.board.set(moves[0], clone.currplayer);
clone.board.set(moves[1], clone.currplayer % 2 + 1 as playerid); // opponent's piece pushed to moves[1]
}

for (const group of clone.getGroups(clone.currplayer)) {
const symmetry = clone.computeSymmetry(group);
if ( symmetry.length === 3 ) { // this group is symmetric!
clone.scores[clone.currplayer - 1] += group.length - 5; // score N-5 points for a group with N pieces
clone._symmetryLine.push(clone.getSymmetryLine(group, symmetry as [number, number, number],
clone.currplayer));
if ( i == actions.length - 1 ) { // consider only for the last available action
hadCaptures = clone.scores[clone.currplayer - 1] < clone.getWinningScore();
}
for (const cell of group) { // symmetric groups must be deleted
clone.board.delete(cell);
}
}
}

// now, do the same for the opponent's groups that might be formed due to currplayer's actions
const prevplayer = clone.currplayer % 2 + 1 as playerid;
for (const group of clone.getGroups(prevplayer)) {
const symmetry = clone.computeSymmetry(group);
if ( symmetry.length === 3 ) { // this group is symmetric!
clone.scores[prevplayer - 1] += group.length - 5; // score N-5 points for a group with N pieces
clone._symmetryLine.push(clone.getSymmetryLine(group, symmetry as [number, number, number],
prevplayer));
for (const cell of group) { // symmetric groups must be deleted
clone.board.delete(cell);
}
}
}
} // for (actions)
return [hadCaptures, clone];
}

public handleClick(move: string, row: number, col: number, piece?: string): IClickResult {
Expand All @@ -177,13 +235,14 @@ export class ShapeChessGame extends GameBase {
newmove = cell;
} else {
// an action might be 'cell' or 'cell-cell1'
// a move is 1+ actions divided by commas, eg: a1,b1-c1,d2
// a new action is only possible if the previous move resulted in a capture
if ( this.hadCaptures(move.split(',').at(-1)!) ) { // a new action begins
// a move is 1+ actions joined by commas, eg: a1,b1-c1,d2
const actions: string[] = move.split(',');

if ( this.willLastActionCapture(move)[0] ) {
// a new action is only possible if the previous move resulted in a capture
newmove = `${move},${cell}`;
} else { // it is the finishing of the current action
const actions: string[] = move.split(',');
if ( actions.at(-1) === cell ) { // if cell (of the current action) is reclicked, reset action
} else { // it is either a conclusion of a partial action, or a action reset
if ( actions.at(-1) === cell ) { // if cell (of the current action) is re-clicked, reset action
newmove = actions.slice(0,-1).join(',');
} else {
newmove = `${move}-${cell}`;
Expand All @@ -209,12 +268,6 @@ export class ShapeChessGame extends GameBase {
.filter(c => !this.board.has(c));
}

private hadCaptures(moves: string) {
const cloned = this.clone();
cloned.move(moves, {trusted: true, partial: true}); // simulate the move execution
return cloned._hadCaptures;
}

public validateMove(m: string): IValidationResult {
const result: IValidationResult = {valid: false,
message: i18next.t("apgames:validation._general.DEFAULT_HANDLER")};
Expand All @@ -231,26 +284,25 @@ export class ShapeChessGame extends GameBase {

// let's execute all previous moves on a clone, which were already validated
// this is necessary, given that some cells might become empty
const cloned = this.clone();
const actions = m.split(',');
cloned.move(actions.slice(0,-1).join(',')); // execute all but the last
const [, cloned] = this.willLastActionCapture(actions.slice(0,-1).join(',')) // run all but last

const moves = actions.at(-1)!.split("-"); // let's validate the last action
if ( moves.length === 1 ) {
result.valid = true;
result.canrender = true;
result.complete = -1;
if (! cloned.board.has(moves[0]) ) {
// if placed on an empty cell, this is a complete move
result.complete = cloned.hadCaptures(m.split(',').at(-1)!) ? -1 : 1;
// if placed on an empty cell, this might be a complete move
result.complete = this.willLastActionCapture(m)[0] ? -1 : 1;
result.message = i18next.t("apgames:validation._general.VALID_MOVE");
} else if ( cloned.board.get(moves[0])! === this.currplayer ) {
// or if placing over a friendly stone, this is a jump
result.message = i18next.t("apgames:validation.shapechess.JUMP_INSTRUCTIONS");
} else {
// otherwise it is over an adversary stone, which is a push
if ( cloned.emptyNeighbors(moves[0]).length === 0 ) {
result.valid = false;
result.valid = false; // however, it cannot be completely surrounded
result.message = i18next.t("apgames:validation.shapechess.PUSH_NO_FREEDOM");
return result;
}
Expand Down Expand Up @@ -278,7 +330,7 @@ export class ShapeChessGame extends GameBase {
}

result.valid = true;
result.complete = this.hadCaptures(m.split(',').at(-1)!) ? -1 : 1;
result.complete = this.willLastActionCapture(m)[0] ? -1 : 1;
result.canrender = true;
result.message = i18next.t("apgames:validation._general.VALID_MOVE");
return result;
Expand Down Expand Up @@ -320,8 +372,8 @@ export class ShapeChessGame extends GameBase {
const pointSet = new Set<string>(descriptions);

// compute group's centroid
const centerX = points.reduce((sum, p) => sum + p[0], 0) / points.length;
const centerY = points.reduce((sum, p) => sum + p[1], 0) / points.length;
const centerX = Math.round(points.reduce((sum, p) => sum + p[0], 0) / points.length * 1000) / 1000;
const centerY = Math.round(points.reduce((sum, p) => sum + p[1], 0) / points.length * 1000) / 1000;

const candidates = [
{ coefs: [1, 0, -centerX] }, // vertical line
Expand All @@ -336,16 +388,16 @@ export class ShapeChessGame extends GameBase {
const rp = this.reflect(p, line.coefs as [number, number, number]); // reflected point
rp[0] = Math.round(rp[0] * 1000) / 1000; // avoiding floating-point shenanigans
rp[1] = Math.round(rp[1] * 1000) / 1000;
return pointSet.has(`${rp[0]},${rp[1]}`);
return pointSet.has(`${rp[0]},${rp[1]}`); // better to compare strings than floats
});
if (isSymmetric) return line.coefs;
}

return [];
}

// find the segment to draw the symmetric line within the bounds of the symmetric group
// at the end, it is added the current player, which is used at the render phase
// find the segment to draw the symmetric line within the bounds of the symmetric group;
// the current player is added at the end, which is used in the render phase
// (this is necessary, because when the turn ends, the currplayer is already updated)
private getSymmetryLine(group: string[], line: [number, number, number], player: playerid): number[][] {
const [a, b, c] = line
Expand All @@ -361,14 +413,10 @@ export class ShapeChessGame extends GameBase {
return [[centerX,minY], [centerX,maxY], [player]]
} else if ( a == 0 ) { // horizontal line
return [[minX,centerY], [maxX,centerY], [player]]
} else if ( a == 1 && b == -1 ) { // diagonal 45º
} else { // diagonal 45º/-45º
const y0 = (-c - a*minX) / b;
const y1 = (-c - a*maxX) / b;
return [[minX,y0], [maxX,y1], [player]];
} else { // diagonal -45º
const y0 = (-c - a*minX) / b;
const y1 = (-c - a*maxX) / b;
return [[minX,y1], [maxX,y0], [player]];
}
}

Expand All @@ -383,7 +431,6 @@ export class ShapeChessGame extends GameBase {
const result = this.validateMove(m);
if (! result.valid) { throw new UserFacingError("VALIDATION_GENERAL", result.message) }
}

if (m.length === 0) { return this; } // note: this allows the re-click cell reset

this.results = [];
Expand Down Expand Up @@ -437,11 +484,10 @@ export class ShapeChessGame extends GameBase {
}
} // for (actions)

this._hadCaptures = false;
const moves = actions.at(-1)!.split("-");

if ( partial && this.board.has(moves![0]) &&
this.board.get(moves![0])! !== this.currplayer) {
if ( partial && moves.length === 1 &&
this.board.has(moves![0]) && this.board.get(moves![0])! !== this.currplayer) {
this._points = this.emptyNeighbors(moves![0]).map(c => this.algebraic2coords(c));
return this;
} else {
Expand Down Expand Up @@ -469,9 +515,6 @@ export class ShapeChessGame extends GameBase {
this.scores[this.currplayer - 1] += group.length - 5; // score N-5 points for a group with N pieces
this._symmetryLine.push(this.getSymmetryLine(group, symmetry as [number, number, number],
this.currplayer));
// if this._hadCaptures is true, the current player continues moving
// however, if winning score was already achieved, no more further moves are needed
this._hadCaptures = this.scores[this.currplayer - 1] < this.getWinningScore();
for (const cell of group) { // symmetric groups must be deleted
this.board.delete(cell);
this.results.push({ type: "capture", where: cell });
Expand Down Expand Up @@ -502,15 +545,6 @@ export class ShapeChessGame extends GameBase {
return this;
}

private getWinningScore() {
if (this.ruleset === "5-pts") return 5;
if (this.ruleset === "6-pts") return 6;
if (this.ruleset === "7-pts") return 7;
if (this.ruleset === "8-pts") return 8;
if (this.ruleset === "9-pts") return 9;
return 4;
}

protected checkEOG(): ShapeChessGame {
const prevplayer: playerid = this.currplayer % 2 + 1 as playerid;
const currScore = this.getPlayerScore(this.currplayer);
Expand Down Expand Up @@ -641,6 +675,15 @@ export class ShapeChessGame extends GameBase {
};
}

private getWinningScore() {
if (this.ruleset === "5-pts") return 5;
if (this.ruleset === "6-pts") return 6;
if (this.ruleset === "7-pts") return 7;
if (this.ruleset === "8-pts") return 8;
if (this.ruleset === "9-pts") return 9;
return 4;
}

public getPlayerScore(player: number): number {
return this.scores[player-1];
}
Expand Down
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