checkers_aka

Small Checkers game ported from gp2x for gamebuino aka

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Project maintained by joyrider3774 Hosted on GitHub Pages — Theme by mattgraham

Checkers for the Gamebuino AKA

A port of the GP2X version of Checkers to the Gamebuino AKA. Play checkers against the computer: you are blue at the bottom, the computer is red at the top. Jumps have to be made when there is one, a piece that jumped and can jump again has to, and a piece that reaches the other side becomes a king that can also go backwards. The options set how far ahead the computer looks (four difficulties) and whether it also counts how many pieces can jump or move. The panel on the right shows whose turn it is and the last moves. The graphics, sounds and music are the GP2X version’s, at the same 320x240 the AKA’s screen has.

Controls

AKA	In a game	In the menus
D-pad / joystick	move the cursor; with a piece picked up, two directions held together move it along that diagonal (it jumps when it can)	choose; left / right change an option
A	pick up a piece; with a piece picked up, move it to the square the cursor is on; after the game, back to the title screen	select; change an option
B	drop the piece that is picked up; cancel	back (options)
MENU	leave the game (asks first)	back (options)
L1 / R1	volume down / up	volume down / up

The squares a picked up piece can go to are shown in green, the cursor in white. Quit in the title screen’s menu, or RUN + MENU held for half a second anywhere in the game, goes back to the launcher; RUN on its own switches the AKA off as in every game.

The GP2X moved a picked up piece with its diagonal buttons. The AKA has none: two directions held together do the same, or move the cursor to the square and press A.

Installing

Copy the SD_files/CHECKERS folder to the root of the SD card and start Checkers from the launcher. The folder holds firmware.bin, meta.json, screen.bmp, the music and the LICENSE. The game writes the volume, the difficulty and the jump option to settings.dat there, as soon as they change.

Building

ESP-IDF 5.5 and the official Gamebuino AKA library, which is used where it is checked out (C:/github/Gamebuino_AKA_lib by default, or set AKA_LIB_DIR):

idf.py set-target esp32s3
idf.py build

build/checkers.bin is copied to SD_files/CHECKERS/firmware.bin by the build.

The graphics, font, sounds and music are the GP2X version’s original files in assets/, converted by tools/convert_assets.py (Pillow, and ffmpeg for the sounds and music):

python tools/convert_assets.py <ffmpeg>

It writes main/assets/assets.bin (the images, the font and the sounds, built into the firmware) and the SD card folder’s music and screen.bmp.

Changes from the GP2X version

• Fixed bugs of the GP2X version:
  • When the computer had no move left, the game asked it again every frame and played the winner sound over and over.
  • A new game still showed the moves of the game before.
  • The computer’s jumps over several pieces were listed from the last jump to the first.
  • Showing the steps of a move one by one read an iterator that was never set (it was never used that way).
  • A damaged settings.dat could give a difficulty the computer can not play at.
• Taken over from the later Playdate version:
  • MENU in a game asks “Are you sure you want to quit the current game?” first (the image is the Playdate one, coloured as the GP2X panels).
  • A draw plays a sound of its own (the Playdate version’s draw.wav).
  • In the options A changes the option instead of leaving the screen.
• A picked up piece is moved with the cursor and A, or with two directions held. While a piece has to jump on it can not be dropped, and a jump it can not make plays the wrong move sound.
• The settings are saved when they change, the GP2X saved them when it quit. The TV out screen position, and the R + d-pad on the title screen that moved it, are gone; SELECT no longer quits from the title screen, Quit does.
• The three other computer players of the GP2X code, which the game never used, are left out.

Source layout

The GP2X version was a single main.cpp, split up here:

File	What it is
main/main.cpp	start up and the state loop
main/titlescreen.cpp, options.cpp, game.cpp	one file per game state
main/CBord.cpp	the board, the rules and the moves
main/ComputerAi.cpp	the computer player, a min max search with alpha beta pruning
main/CSelector.cpp, CMainMenu.cpp, COptionMenu.cpp	the cursor, the title menu and the options menu
main/gamefuncs.cpp, commonvars.cpp	what the states share: images, volume, settings, music, the globals
main/gfx.cpp, sound.cpp, input.cpp, platform.cpp	what SDL did on the GP2X, on the AKA library

Credits

Checkers by Willems Davy (Willems Soft).

The music is “Checkers Rag” by Harry J. Lincoln (1913), the MIDI with notes by John Cowles (5/1/96), from primeshop.com/midlist3.htm.

License

MIT, see LICENSE.