Mercurial > hg > terminal-chess / file diff

--- a/src/chess/rules.h	Fri Aug 21 16:08:50 2026 +0200
+++ b/src/chess/rules.h	Fri Aug 21 17:04:43 2026 +0200
@@ -144,6 +144,8 @@
     bool checkmate;
     bool stalemate;
     bool threefold;
+    /** drawn due to insufficient material on both sides */
+    bool nomaterial;
     /** flag is only set when players agreed on remis */
     bool remis;
     bool wresign;
@@ -196,7 +198,8 @@
 }
 
 static inline bool is_game_drawn(const GameState *gamestate) {
-    return gamestate->threefold || gamestate->stalemate || gamestate->remis;
+    return gamestate->threefold || gamestate->stalemate
+        || gamestate->nomaterial || gamestate->remis;
 }
 
 static inline bool is_game_running(const GameState *gamestate) {
@@ -208,6 +211,10 @@
     return gamestate->moves[gamestate->movecount - 1].check;
 }
 
+static inline Color field_color(Row r, File f) {
+    return (r + f) % 2 == 0 ? BLACK : WHITE;
+}
+
 /**
  * Initializes a game state and prepares the chess board.
  * @param gamestate the game state to initialize
@@ -600,5 +607,19 @@
  */
 bool check_threefold_repetition(const GameState *gamestate);
 
+/**
+ * Checks if neither side has enough material left to win the game.
+ *
+ * Returns true if for both players one of the following three cases are true:
+ * - they have only the king left
+ * - they have a king + knight and the opponent has king + queens
+ * - they have a king + bishop and the opponent doesn't have
+ *   opposite color bishops or knights or pawns
+ *
+ * @param gamestate the current game state
+ * @return true if neither side can win due to insufficient material
+ */
+bool check_no_material(const GameState *gamestate);
+
 #endif	/* RULES_H */