tetris-c/README.md

Tetris (C + SDL3)

A small Tetris clone written in C using SDL3 for rendering/input and SDL3_ttf for text.

Build

Requirements:

• CMake (3.7+)
• SDL3
• A C compiler (gcc/clang)

Configure and build:

cmake -S . -B build
cmake --build build

Run:

./build/tetris

Controls

• Move left: Left or A
• Move right: Right or D
• Rotate: Up or W
• Soft drop: Down or S
• Quit: Q or Esc

Gameplay Notes

• The board is 10 x 16 (include/grid.h).
• Shapes are stored as an origin block plus 3 relative offsets (src/shape.c).
• Rotation uses a 90-degree transform around the origin: (x, y) -> (-y, x) (src/game.c).
• Collision checks allow negative y values so pieces can spawn/rotate partly above the visible top (src/grid.c).
• Line clear logic re-checks the same row index after a clear, because rows above are shifted down (src/grid.c).

Debug Logging

Debug logs are compiled in when APP_DEBUG is enabled (for example in Debug builds through CMake).