Sylpheed/tools/port/verify-dwell

#!/usr/bin/env bash
# Check the port's boot pacing against captures of the real game.
#
#   tools/port/verify-dwell
#
# WHY THIS IS A TOOL AND NOT A ONE-OFF. Doing it by hand once already refuted a
# 🔴 I had filed myself: `docs/port/BLOCKED.md` said `rest.t` was the wrong settle
# landmark AND that "everything the sequencer paces off it is therefore late".
# The first half is true; the second was wrong, and I nearly re-paced screens
# that already matched the game to 0.05 s.
#
# ⚠️ A PORT'S TRANSITION INTERVAL IS NOT THE ORACLE'S VISIBLE SPAN. They differ
# by the black hold between screens, and confusing the two cost this corpus 0.6 s
# once and 0.48 s on the plate delay. So the comparison here is explicit: the
# port's interval is checked against the oracle's span PLUS the measured hold.
#
# 🔴 AND THE VERDICT DOES NOT COME FROM THE FILMSTRIP ANY MORE. It used to
# measure ink spans from `--film` frames. The boot's black hold is 0.17-0.23 s
# (HANDOFF Q7) -- shorter than the 0.25 s cadence meant to observe it -- so when
# the black frame fell between samples two screens merged into one span and this
# tool reported `developer logos` as 93 s against an oracle of 3.5 s. Filming at
# 0.1 s made it WORSE: 2.5x the screenshots slows the run enough that the capture
# catches up in bursts, and the publisher span came back as 7.80 s.
#
# The sequencer already knows exactly when it changed screens and prints it.
# Sampling a picture to rediscover a number the program can state is how this
# went wrong. The filmstrip is kept, and marked advisory.
#
# THE EXPECTED NUMBERS ARE THE ORACLE'S, NOT THE PORT'S: three cold boots from
# `docs/re/boot-order-and-splash-dwell.md`, quoted as a test fixture. Nothing in
# the port derives them and nothing may.
set -euo pipefail
cd "${PROJECT_DIR:-/work}"
export DISPLAY="${DISPLAY:-:97}"
OUT="${OUT:-$(mktemp -d)}"
mkdir -p "$OUT"
INTERVAL="${INTERVAL:-0.25}"

echo "running the boot (the intro is skipped -- the splashes are what this measures)"
timeout "${TIMEOUT:-300}" godot --path port --resolution 1280x720 -- \
  --boot --skip-at=1 "--film-interval=$INTERVAL" "--film=$OUT/f" \
  >"$OUT/boot.log" 2>&1 || true

INTERVAL="$INTERVAL" python3 - "$OUT" <<'PYEOF'
import glob, os, re, subprocess, sys
out = sys.argv[1]
INTERVAL = float(os.environ.get("INTERVAL", "0.25"))
# The boot's black gap, measured in the DRAW STREAM (4 presented frames at
# 2.284 units/frame = 9.1 units), not from luminance -- luminance cannot separate
# the outgoing fade's tail from true black. The +/-1 frame range is 6.9-11.4
# units = 0.114-0.190 s. HANDOFF Q7's luminance figure of 0.17-0.23 s overlaps
# only at the top, and the draw-stream number is the one to use.
HOLD_LO, HOLD_HI = 0.114, 0.190

marks = []
for line in open(os.path.join(out, "boot.log"), errors="replace"):
    m = re.match(r"\s+-> (\S+) at ([0-9.]+) s", line)
    if m:
        marks.append((m.group(1), float(m.group(2))))
if not marks:
    print("no transitions in the boot log -- see", os.path.join(out, "boot.log"))
    raise SystemExit(2)

ORACLE = [
    ("publisher wordmark", [4.297, 4.604, 4.370]),
    ("developer logos",    [3.508, 3.503, 3.366]),
]
starts = [0.0] + [t for _, t in marks]
print()
print("%-20s %-14s %-26s %s" % ("screen", "port interval", "oracle span (3 boots)", "verdict"))
bad = 0
for k, (name, runs) in enumerate(ORACLE):
    if k + 1 >= len(starts):
        print("%-20s %-14s %s" % (name, "-", "no such transition this run")); continue
    d = starts[k + 1] - starts[k]
    lo, hi = min(runs) + HOLD_LO, max(runs) + HOLD_HI
    ok = lo - 0.15 <= d <= hi + 0.15
    bad += 0 if ok else 1
    print("%-20s %-14s %-26s %s"
          % (name, "%.2f s" % d, "%.3f / %.3f / %.3f" % tuple(runs),
             "agrees" if ok else "DIFFERS"))
print()
print("  An interval is the oracle's SPAN plus the black hold (%.2f-%.2f s)," % (HOLD_LO, HOLD_HI))
print("  compared against span+hold with 0.15 s of slack for wall-clock jitter.")
print("  transitions:", ", ".join("%s@%.2f" % m for m in marks[:4]))

frames = sorted(glob.glob(os.path.join(out, "f_*.png")))[:120]
if frames:
    means = [float(subprocess.run(["convert", f, "-colorspace", "Gray", "-format",
             "%[fx:mean*255]", "info:"], capture_output=True, text=True).stdout or 0)
             for f in frames]
    ink = [m > 0.0 for m in means]
    spans, i = [], 0
    while i < len(ink):
        if ink[i]:
            j = i
            while j < len(ink) and ink[j]: j += 1
            spans.append((i * INTERVAL, j * INTERVAL)); i = j
        else:
            i += 1
    print()
    print("  advisory -- filmstrip ink spans at %.2f s, which CANNOT resolve a" % INTERVAL)
    print("  %.2f-%.2f s hold and merges screens whenever it misses one:" % (HOLD_LO, HOLD_HI))
    for a, b in spans[:4]:
        print("     %6.2f - %6.2f s   (%.2f s)" % (a, b, b - a))
raise SystemExit(1 if bad else 0)
PYEOF
rc=$?
echo "artifacts in $OUT"
exit $rc