Chess Master

A complete 2D chess game for Godot 4.6 (GDScript): you play White (or Black) against a minimax engine with full chess rules, animated pieces and a dark wood theme.

Open the folder in Godot and press Play (scenes/main.tscn is the main scene).

Playing

• Click a piece, then click a highlighted square. Green dot = move, red ring = capture.
• Or drag a piece onto its target square; dropping anywhere else puts it back.
• Gold = selected piece, blue = last move, pulsing red = king in check.
• Pawn reaching the last rank opens a promotion picker (click outside to cancel).
• Side panel: captured pieces, move list (SAN), New Game, Undo (takes back your move and the reply), Flip Board, Resign, Offer Draw (the AI accepts only when it is losing), Copy FEN, Load a FEN, AI search depth (1–6), sound, Play as Black.
• Right-click deselects.

Draws by stalemate, threefold repetition, fifty-move rule and insufficient material are detected.

Project layout

scenes/main.tscn            UI layout (board area, side panel, promotion picker, game-over banner)
scripts/chess/              Rules engine, no scene dependencies
  chess_position.gd         Board state, move generation, make/unmake, check, FEN, Zobrist hashing
  chess_move.gd             Packed-int move encoding helpers
  notation.gd               SAN generation, UCI parsing
scripts/ai/chess_ai.gd      Negamax + alpha-beta, iterative deepening, quiescence, killers, evaluation
scripts/ui/                 game_controller.gd (flow + AI thread), board_view.gd, side_panel.gd,
                            promotion_dialog.gd, piece_textures.gd
assets/pieces/*.svg         Piece set (generated; replace the 12 files to change the look)
assets/sfx/*.wav            Move / capture / check / game-end sounds (generated)
assets/ui/theme.tres        Dark UI theme
tools/gen_assets.py         Regenerates pieces, sounds and the icon (stdlib Python)
tests/perft.gd              Engine self-check; tests/screenshot.gd drives the UI and saves PNGs
docs/superpowers/specs/     Design notes

Tests

godot --headless --path . --script tests/perft.gd

Checks perft node counts on the standard test positions (castling, en passant, promotions, checks), FEN round-trips, make/unmake integrity, game status, SAN and that the AI finds forced mates. Add ++ deep for the slower perft depths.

godot --path . --script tests/screenshot.gd ++ /absolute/output/dir

Plays a scripted game through simulated clicks and saves screenshots (needs a display).

Engine notes

• Board is a 64-int array (color * piece_type), moves are packed ints, undo records are packed int64s: the search never allocates objects, which keeps GDScript fast enough for depth 3 in well under a second and depth 4 in a few seconds.
• Evaluation: material, piece-square tables (middlegame/endgame king tables), doubled and isolated pawns, pawn shield in front of the king, piece mobility.
• The AI searches a copy of the position on a worker thread; the UI stays responsive and Undo / New Game abort the search.
• Extending: a transposition table keyed by ChessPosition.hash is the natural next step for depth 5+; an opening book can pick moves before calling ChessAI.find_best_move.