chess-puzzles

commit d1450a9bf4d9b009733094038420a82a6872a8ae
parent 09a541233ed6f1abf9f4498b37d1281a78f65ce8
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Tue, 19 Dec 2023 00:31:55 +0100

implement detecting castling for moves

Diffstat:
M
fen_to_svg.c
 | 
33
++++++++++++++++++++++++++++++++-

1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/fen_to_svg.c b/fen_to_svg.c
@@ -286,7 +286,38 @@ main(int argc, char *argv[])
 			place(piece, x2, y2);
 			s += 2;
 
-			/* possible promotion? (queen, knight, bishop) */
+			/* castling */
+			if (piece == 'K' && y == 7 && y2 == 7 && x == 4) {
+				/* white: kingside castling: "e1g1" */
+				if (x2 == 6) {
+					place('R', x2 - 1, y2);
+					x2 = 7;
+					y2 = 7;
+					place(0, x2, y2); /* clear rook square */
+				} else if (x2 == 2) {
+					/* white: queenside castling: "e1c1" */
+					place('R', x2 + 1, y2);
+					x2 = 0;
+					y2 = 7;
+					place(0, x2, y2);
+				}
+			} else if (piece == 'k' && y == 0 && y2 == 0 && x == 4) {
+				/* black: kingside castling: "e8g8" */
+				if (x2 == 6) {
+					place('r', x2 - 1, y2);
+					x2 = 7;
+					y2 = 0;
+					place(0, x2, y2); /* clear rook square */
+				} else if (x2 == 2) {
+					/* black: queenside castling: "e8c8" */
+					place('r', x2 + 1, y2);
+					x2 = 0;
+					y2 = 0;
+					place(0, x2, y2); /* clear rook square */
+				}
+			}
+
+			/* possible promotion: queen, knight, bishop */
 			if (*s == 'q' || *s == 'n' || *s == 'b') {
 				if (side_to_move == 'w')
 					piece = toupper(*s);