Tic-Tac-Toe Example

A tic-tac-toe game against an AI (minimax-style move search with configurable error chance). The board is drawn with primitive rendering (grid, X/O, cursor). UI uses UILabel for status text and either UIButton or UITouchButton depending on touch support.

On esp32cyd, PIXELROOT32_ENABLE_TOUCH and onUnconsumedTouchEvent map taps to cells; native / esp32dev use cursor + confirm-style input per GameConstants.h button IDs.

Requirements (build flags)

• PIXELROOT32_ENABLE_TOUCH=1 on native and esp32cyd (see platformio.ini) so touch code paths compile where used.
• ESP32 Dev preset does not set touch in platformio.ini — use GPIO DPAD + A (or equivalent) as in GameConstants.h (BTN_UP, BTN_DOWN, BTN_PREV, BTN_NEXT, BTN_SELECT).

PIXELROOT32_ENABLE_UI_SYSTEM defaults to on in the engine (PlatformDefaults.h).

See platformio.ini for native, esp32dev, and esp32cyd (CYD uses ILI9341 240×320 + XPT2046 touch — many calibration defines are in the INI).

Platforms

Environment	Display / input
native	SDL2, 240×240, simulated touch enabled
esp32dev	ST7789 240×240, no touch flags in INI
esp32cyd	ILI9341 240×320 + resistive touch (XPT2046 GPIO SPI)

Controls (GPIO / keyboard)

• Navigate / change cell / confirm per src/GameConstants.h (BTN_* indices).
• Play Again: reset control wired in TicTacToeScene::createResetButton() (GPIO or touch widget depending on build).

Touch (CYD)

Touches that the UI does not consume are handled in onUnconsumedTouchEvent, with hit slop around each cell (kTouchHitSlop in TicTacToeScene.h).

Features

• Scene lifecycle + UI labels and conditional touch / GPIO buttons
• TouchEvent pipeline for board placement
• AI: computeAIMove, win detection, draw state
• Custom palette and vector draw for marks (no tilemap required for the board)

Documentation links

• UI API
• Input API
• Core API

Build

From examples/tic_tac_toe:

pio run -e native
pio run -e esp32dev
pio run -e esp32cyd

Upload (ESP32)

pio run -e esp32dev --target upload
pio run -e esp32cyd --target upload