#!/usr/bin/env bash

# git-doom — play DOOM as a truecolor terminal movie whose frames live in git commits.

#

# producer: ./git-doom play # render + append every frame as a commit

# consumer: ./git-doom watch # follow HEAD, render the newest frame

# ./git-doom replay # walk the main branch from the start

#

# Frames are commits on the `main` branch of a data repo; saves are git tags

# carrying the real engine state. Producer and consumer share only that repo.

set -euo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

BIN="$ROOT/doomgeneric/git-doom-play"

WAD="${GITDOOM_WAD:-$ROOT/doom1.wad}"

REPO="${GITDOOM_REPO:-$ROOT/game-data}"

BRANCH="${GITDOOM_BRANCH:-main}"

export GITDOOM_REPO GITDOOM_BRANCH

show() { git --no-pager -C "$REPO" show -s --format='%B' "$1"; } # --no-pager: don't open less per frame

usage() {

cat <<EOF

git-doom — DOOM frames stored in git commits

./git-doom build compile the engine (doomgeneric + git render layer)

./git-doom play [WxH] [doom-args]

play; render locally and commit every frame. An

optional WxH (e.g. 120x40) pins an exact fixed size;

otherwise it auto-fits the terminal.

(try: ./git-doom play -warp 1 1 to skip to E1M1)

charset: GITDOOM_CHARSET=color (default, solid

truecolor blocks — no gaps) | half (2x vertical

res, needs a terminal that tiles ▀ cleanly)

./git-doom watch follow the main branch, render the newest frame

./git-doom replay [fps] replay the whole main branch (default 15 fps)

./git-doom saves list save tags

./git-doom thumb <name> print a save's thumbnail

./git-doom clean remove the data repo and scratch savegame dir

./git-doom gc pack/prune the data repo

In-game keys: arrows or w/a/s/d move+turn · , . (or q/e) strafe · space fire

f use/open · 1-7 weapon · tab map · esc menu (Save/Load Game)

· ctrl-c quit. (Terminals can't send Ctrl/Shift/Alt, so fire=space.)

EOF

}

cmd="${1:-}"; shift || true

case "$cmd" in

build)

make -C "$ROOT/doomgeneric" -f Makefile.git "$@"

;;

play)

[ -x "$BIN" ] || { echo "engine not built — run: ./git-doom build" >&2; exit 1; }

[ -f "$WAD" ] || { echo "no WAD at $WAD (set GITDOOM_WAD)" >&2; exit 1; }

# Optional first arg WxH pins an exact fixed size; otherwise the engine

# autoscales to the terminal and follows live resizes.

pinned=0

if [[ "${1:-}" =~ ^[0-9]+x[0-9]+$ ]]; then

GITDOOM_COLS="${1%x*}"; GITDOOM_ROWS="${1#*x}"; shift; pinned=1

fi

[ -n "${GITDOOM_COLS:-}${GITDOOM_ROWS:-}" ] && pinned=1

export GITDOOM_CHARSET="${GITDOOM_CHARSET:-color}"

commit=${GITDOOM_COMMIT:-1}

[ "$commit" = 1 ] && \

echo "note: truecolor recording throttles play to git's speed (no frames dropped). GITDOOM_COMMIT=0 to skip recording." >&2

if [ "$pinned" = 1 ]; then

tcols=$(tput cols 2>/dev/null || echo 999); tlines=$(tput lines 2>/dev/null || echo 999)

echo "rendering ${GITDOOM_COLS}x${GITDOOM_ROWS} ${GITDOOM_CHARSET} (fixed)" >&2

if [ "${GITDOOM_COLS}" -gt "$tcols" ] || [ "${GITDOOM_ROWS}" -gt "$((tlines - 1))" ]; then

echo "warning: bigger than your ${tcols}x${tlines} terminal — it'll be clipped. Drop the size to autoscale." >&2

fi

exec env GITDOOM_RENDER=1 GITDOOM_COMMIT="$commit" GITDOOM_COLS="${GITDOOM_COLS}" GITDOOM_ROWS="${GITDOOM_ROWS}" \

"$BIN" -iwad "$WAD" "$@"

else

echo "autoscaling to the terminal — resize freely · ${GITDOOM_CHARSET}" >&2

exec env GITDOOM_RENDER=1 GITDOOM_COMMIT="$commit" GITDOOM_AUTOSCALE=1 \

"$BIN" -iwad "$WAD" "$@"

fi

;;

watch)

git -C "$REPO" rev-parse "refs/heads/$BRANCH" >/dev/null 2>&1 || echo "waiting for branch '$BRANCH'…" >&2

printf '\033[?1049h\033[2J\033[?25l'

trap 'printf "\033[?25h\033[?1049l"' EXIT

last=""

while :; do

sha=$(git -C "$REPO" rev-parse "refs/heads/$BRANCH" 2>/dev/null || true)

if [ -n "$sha" ] && [ "$sha" != "$last" ]; then

printf '\033[H'; show "$sha"; last="$sha"

fi

sleep 0.03

done

;;

replay)

fps="${1:-15}"

delay=$(awk "BEGIN{printf \"%.4f\", 1/$fps}")

printf '\033[?1049h\033[2J\033[?25l'

trap 'printf "\033[?25h\033[?1049l"' EXIT

for sha in $(git -C "$REPO" rev-list --reverse "refs/heads/$BRANCH"); do

printf '\033[H'; show "$sha"; sleep "$delay"

done

;;

saves)

git -C "$REPO" for-each-ref --format='%(refname:short) %(subject)' 'refs/tags/save/*' \

|| echo "no saves yet"

;;

thumb)

name="${1:?usage: git-doom thumb <name>}"

git -C "$REPO" cat-file blob "save/$name^{tree}:thumb.txt"

;;

clean)

rm -rf "$REPO" "$ROOT/.savegame"

echo "removed data repo and scratch savegame dir"

;;

gc)

git -C "$REPO" gc --prune=now

;;

""|-h|--help|help) usage ;;

*) echo "unknown command: $cmd" >&2; usage; exit 1 ;;

esac