Implements castling.

aryann · Oct 16, 2024 · 6d7b9df · 6d7b9df
1 parent d9db54c
commit 6d7b9df
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Showing 5 changed files with 104 additions and 17 deletions.
diff --git a/engine/src/board.ts b/engine/src/board.ts
@@ -113,6 +113,18 @@ export class BoardState {
 
         this.board[toIndex] = move.promoteTo.charCodeAt(0);
         break;
+
+      case "castling":
+        this.board[toIndex] = this.board[fromIndex];
+
+        const rookFromIndex = this.toIndex(move.rook.from);
+        const rookToIndex = this.toIndex(move.rook.to);
+        this.board[rookToIndex] = this.board[rookFromIndex];
+
+        this.board[fromIndex] = 0;
+        this.board[rookFromIndex] = 0;
+
+        break;
     }
 
     this.board[fromIndex] = 0;
@@ -171,7 +183,22 @@ export class BoardState {
           this.board[toIndex] = 0;
         }
 
-        this.board[fromIndex] = this.pieceToInt(this.isWhiteTurn ? "P" : "p");
+        console.log(state.move.promoteTo, this.isWhiteTurn);
+        this.board[fromIndex] = this.pieceToInt(
+          getSide(state.move.promoteTo) === "w" ? "P" : "p"
+        );
+        break;
+
+      case "castling":
+        this.board[fromIndex] = this.board[toIndex];
+
+        const rookFromIndex = this.toIndex(state.move.rook.from);
+        const rookToIndex = this.toIndex(state.move.rook.to);
+        this.board[rookFromIndex] = this.board[rookToIndex];
+
+        this.board[toIndex] = 0;
+        this.board[rookToIndex] = 0;
+
         break;
     }
 

diff --git a/engine/src/moves.test.ts b/engine/src/moves.test.ts
@@ -975,8 +975,18 @@ describe("castling", () => {
     assert.sameDeepMembers(generator.generateMoves("e1"), [
       { type: "normal", from: "e1", to: "f1" },
       { type: "normal", from: "e1", to: "d1" },
-      { type: "normal", from: "e1", to: "g1" },
-      { type: "normal", from: "e1", to: "c1" },
+      {
+        type: "castling",
+        from: "e1",
+        to: "g1",
+        rook: { from: "h1", to: "f1" },
+      },
+      {
+        type: "castling",
+        from: "e1",
+        to: "c1",
+        rook: { from: "a1", to: "d1" },
+      },
     ]);
   });
 
@@ -986,7 +996,12 @@ describe("castling", () => {
     assert.sameDeepMembers(generator.generateMoves("e1"), [
       { type: "normal", from: "e1", to: "f1" },
       { type: "normal", from: "e1", to: "d1" },
-      { type: "normal", from: "e1", to: "g1" },
+      {
+        type: "castling",
+        from: "e1",
+        to: "g1",
+        rook: { from: "h1", to: "f1" },
+      },
     ]);
   });
 
@@ -996,7 +1011,12 @@ describe("castling", () => {
     assert.sameDeepMembers(generator.generateMoves("e1"), [
       { type: "normal", from: "e1", to: "f1" },
       { type: "normal", from: "e1", to: "d1" },
-      { type: "normal", from: "e1", to: "c1" },
+      {
+        type: "castling",
+        from: "e1",
+        to: "c1",
+        rook: { from: "a1", to: "d1" },
+      },
     ]);
   });
 
@@ -1006,8 +1026,18 @@ describe("castling", () => {
     assert.sameDeepMembers(generator.generateMoves("e8"), [
       { type: "normal", from: "e8", to: "f8" },
       { type: "normal", from: "e8", to: "d8" },
-      { type: "normal", from: "e8", to: "g8" },
-      { type: "normal", from: "e8", to: "c8" },
+      {
+        type: "castling",
+        from: "e8",
+        to: "g8",
+        rook: { from: "h8", to: "f8" },
+      },
+      {
+        type: "castling",
+        from: "e8",
+        to: "c8",
+        rook: { from: "a8", to: "d8" },
+      },
     ]);
   });
 
@@ -1017,7 +1047,12 @@ describe("castling", () => {
     assert.sameDeepMembers(generator.generateMoves("e8"), [
       { type: "normal", from: "e8", to: "f8" },
       { type: "normal", from: "e8", to: "d8" },
-      { type: "normal", from: "e8", to: "g8" },
+      {
+        type: "castling",
+        from: "e8",
+        to: "g8",
+        rook: { from: "h8", to: "f8" },
+      },
     ]);
   });
 
@@ -1027,7 +1062,12 @@ describe("castling", () => {
     assert.sameDeepMembers(generator.generateMoves("e8"), [
       { type: "normal", from: "e8", to: "f8" },
       { type: "normal", from: "e8", to: "d8" },
-      { type: "normal", from: "e8", to: "c8" },
+      {
+        type: "castling",
+        from: "e8",
+        to: "c8",
+        rook: { from: "a8", to: "d8" },
+      },
     ]);
   });
 });
diff --git a/engine/src/moves.ts b/engine/src/moves.ts
@@ -292,7 +292,15 @@ export class MoveGenerator {
       const right = SQUARES[rank * NUM_FILES + file + 1];
       const rightRight = SQUARES[rank * NUM_FILES + file + 2];
       if (!this.board.get(right) && !this.board.get(rightRight)) {
-        moves.push({ type: "normal", from, to: rightRight });
+        moves.push({
+          type: "castling",
+          from,
+          to: rightRight,
+          rook: {
+            from: (from === "e1" ? "h1" : "h8") as TSquare,
+            to: (from === "e1" ? "f1" : "f8") as TSquare,
+          },
+        });
       }
     }
 
@@ -303,7 +311,15 @@ export class MoveGenerator {
       const left = SQUARES[rank * NUM_FILES + file - 1];
       const leftLeft = SQUARES[rank * NUM_FILES + file - 2];
       if (!this.board.get(left) && !this.board.get(leftLeft)) {
-        moves.push({ type: "normal", from, to: leftLeft });
+        moves.push({
+          type: "castling",
+          from,
+          to: leftLeft,
+          rook: {
+            from: (from === "e1" ? "a1" : "a8") as TSquare,
+            to: (from === "e1" ? "d1" : "d8") as TSquare,
+          },
+        });
       }
     }
 

diff --git a/engine/src/perft.test.ts b/engine/src/perft.test.ts
@@ -1,7 +1,7 @@
 import { assert, describe, it } from "vitest";
 import { BoardState } from "./board";
 import { MoveGenerator } from "./moves";
-import { getSide, SQUARES } from "./types";
+import { getSide, SQUARES, TMove } from "./types";
 
 const visit = (
   states: number[],
@@ -15,17 +15,20 @@ const visit = (
     return;
   }
 
+  const moves: TMove[] = [];
   for (const from of SQUARES) {
     const piece = board.get(from);
     if (!piece || getSide(piece) !== board.sideToMove()) {
       continue;
     }
 
-    for (const move of moveGenerator.generateMoves(from)) {
-      board.move(move);
-      visit(states, depth + 1, board, moveGenerator);
-      board.undo();
-    }
+    moves.push(...moveGenerator.generateMoves(from));
+  }
+
+  for (const move of moves) {
+    board.move(move);
+    visit(states, depth + 1, board, moveGenerator);
+    board.undo();
   }
 };
 

diff --git a/engine/src/types.ts b/engine/src/types.ts
@@ -120,4 +120,5 @@ export type TMove = {
   | { type: "normal" }
   | { type: "promotion"; promoteTo: TPiece }
   | { type: "enPassant" }
+  | { type: "castling"; rook: { from: TSquare; to: TSquare } }
 );