cppautomata

Conway's Game of Life as a terminal screensaver, written in C++ with ncurses.

cppautomata

cppautomata -r -t 00:10:00 ●

cppautomata 🐉

• Full screen grid sized to your terminal, with toroidal wrapping: whatever leaves one edge comes back from the opposite one
• Random, glider or blinker starting pattern
• Any string as the live cell glyph: a block, an emoji, a Nerd Font icon
• Eight foreground and background colors, plus a rainbow mode that cycles the 256 color palette
• Automatic restart after N generations or after a set run time, so it can run unattended
• Live keys to restart and switch colors without quitting
• Man page included: man cppautomata

Contents

• Requirements
• Install
• Usage
• Keys
• Examples
• How it works
• Notes
• License

Requirements

• A C++ compiler (g++)
• make
• ncurses with wide character support (ncursesw), needed for Unicode glyphs

Install

git clone https://github.com/Riccardo-Martelli/cppautomata.git
cd cppautomata
make

This compiles the program and installs the binary to ~/.local/bin and the man page to ~/.local/share/man/man1. Then run it from anywhere:

cppautomata
man cppautomata

If the shell says command not found, ~/.local/bin is not in your PATH. Add it:

echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.bashrc
source ~/.bashrc

Other targets:

Usage

cppautomata [options] [glyph]

  --version     show cppautomata version and exit
  -c COLOR      foreground color of live cells (default: red)
  -b COLOR      background color (default: black)
  -v MS         milliseconds between generations, integer > 0 (default: 100)
  -s N          restart every N generations, 0 = never (default: 0)
  -t HH:MM:SS   restart after this much run time (default: never)
  -m MODE       initial pattern: random, glider, blinker (default: random)
  -r            rainbow mode: change the foreground color at every generation
  -h            show help and exit

colors:
  black, red, green, yellow, blue, magenta, cyan, white

glyph is the string drawn for each live cell. The default is a full block █.

Keys

Examples

cppautomata                          # default: random start, red blocks on black
cppautomata -c green -v 50 -s 500    # faster, restarts every 500 generations
cppautomata -m glider -c cyan o      # a single glider drawn with the letter o
cppautomata -r -t 00:10:00 ●         # rainbow dots, restart every 10 minutes
cppautomata 🐉                       # dragons

How it works

Each generation is computed on a fresh copy of the grid, so every cell sees the previous state of its neighbours. A cell counts its eight neighbours, with the indices wrapped around the edges so the board is a torus, and the standard rules apply:

The new grid is then drawn cell by cell with ncurses and the program sleeps for the interval set by -v.

Notes

• Wide glyphs (emoji, some Nerd Font icons) take two terminal columns, so they overlap their right neighbour. Single width glyphs give the cleanest grid.
• The grid size is read once at startup: resizing the terminal does not resize the board.
• The -t timer counts the sleep intervals, not wall clock time, so on large grids the real time before a restart is slightly longer.
• Rainbow mode looks best in a 256 color terminal.
• There is a universe behind cellular automata and more can be done to make this simulation more interesting, for more information see Conway's Game of Life.

License

MIT, see LICENSE.