#!/usr/bin/env bash
# Renders the black_hole_interstellar example to
# out/black_hole_interstellar.mp4: 1920x1080, 60 fps, 60 s. Captures every tick at 3840x2160 through a
# headless scenario and scales down to 1080p, so the photon ring and the
# lensed stars come out supersampled instead of flickering.
set -euo pipefail
cd "$(dirname "$0")/.."

frames=3600
mkdir -p out
rm -rf out/gargantua_frames
mkdir out/gargantua_frames

steps=$(for ((i = 0; i < frames; i++)); do
    printf '{"tick":%d,"capture":{"path":"gargantua_frames/%05d.png","hud":false}},' "$i" "$i"
done)
printf '{"name":"gargantua video","ticks":%d,"capture_size":[3840,2160],"steps":[%s]}\n' \
    "$frames" "${steps%,}" > out/gargantua.scenario.json

cargo build --release --features window --example black_hole_interstellar
RUSTING_TEST_SCENARIO=out/gargantua.scenario.json RUSTING_TEST_STALL_SECS=0 \
    target/release/examples/black_hole_interstellar

ffmpeg -nostdin -y -loglevel error -framerate 60 -i out/gargantua_frames/%05d.png \
    -vf scale=1920:1080:flags=lanczos \
    -c:v libx264 -preset slow -crf 14 -pix_fmt yuv420p -movflags +faststart \
    out/black_hole_interstellar.mp4
rm -rf out/gargantua_frames out/gargantua.scenario.json
echo "wrote out/black_hole_interstellar.mp4"