Rendering vtk files of AcoDyn and Jaali x Prestige particles

render_vtk_acodyn_jaali_prestige.sh

#!/usr/bin/env bash
set -euo pipefail

# ── ParaView (Linux custom install) ──────────────────────────
PARAVIEW_DIR="/home/dineshadepu/life/softwares/paraview"
export LD_LIBRARY_PATH="${PARAVIEW_DIR}/lib${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}"
PVPYTHON="${PARAVIEW_DIR}/bin/pvpython"

# ── Paths ────────────────────────────────────────────────────
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
VIS="${SCRIPT_DIR}/visualize.py"
VIDEO="${SCRIPT_DIR}/simulation.mp4"

# ── Sanity checks ─────────────────────────────────────────────
[[ -f "${VIS}" ]]       || { echo "ERROR: vis script not found: ${VIS}"; exit 1; }
[[ -x "${PVPYTHON}" ]]  || { echo "ERROR: pvpython not found: ${PVPYTHON}"; exit 1; }
command -v ffmpeg &>/dev/null || { echo "ERROR: ffmpeg not in PATH"; exit 1; }

# Pick the best available video encoder
FFMPEG_CODEC=""
FFMPEG_EXTRA_ARGS=""
_enc_list=$(ffmpeg -hide_banner -encoders 2>/dev/null | awk '{print $2}')
for _codec in libx264 libx265 libvpx_vp9 libvpx mpeg4 mjpeg ffv1; do
    if echo "${_enc_list}" | grep -qx "${_codec}"; then
        FFMPEG_CODEC="${_codec}"
        break
    fi
done
[[ -n "${FFMPEG_CODEC}" ]] || {
    echo "ERROR: no suitable video encoder found in ffmpeg"
    exit 1
}
case "${FFMPEG_CODEC}" in
    libx264|libx265) FFMPEG_EXTRA_ARGS="-crf 16 -pix_fmt yuv420p"; VIDEO_EXT="mp4"  ;;
    libvpx_vp9)      FFMPEG_EXTRA_ARGS="-crf 16 -b:v 0";           VIDEO_EXT="webm" ;;
    libvpx)          FFMPEG_EXTRA_ARGS="-crf 16 -b:v 0";           VIDEO_EXT="webm" ;;
    mpeg4)           FFMPEG_EXTRA_ARGS="-q:v 3";                    VIDEO_EXT="mp4"  ;;
    mjpeg)           FFMPEG_EXTRA_ARGS="-q:v 3";                    VIDEO_EXT="mp4"  ;;
    ffv1)            FFMPEG_EXTRA_ARGS="";                          VIDEO_EXT="mkv"  ;;
esac
VIDEO="${SCRIPT_DIR}/simulation.${VIDEO_EXT}"
echo "ffmpeg encoder: ${FFMPEG_CODEC}  container: .${VIDEO_EXT}"

cd "${SCRIPT_DIR}"

ENCODE_ONLY=0
[[ "${1:-}" == "--encode-only" ]] && ENCODE_ONLY=1

if [[ "${ENCODE_ONLY}" -eq 0 ]]; then
    # ── 1/2  Render frames ────────────────────────────────────────
    echo "[1/2] Rendering frames with pvpython..."
    "${PVPYTHON}" --force-offscreen-rendering "${VIS}"
else
    echo "[1/2] Skipping render (--encode-only)."
fi

N_FRAMES=$(ls frame.*.png 2>/dev/null | wc -l | tr -d ' ')
echo "      ${N_FRAMES} frame(s) found."

if [[ "${N_FRAMES}" -eq 0 ]]; then
    echo "ERROR: no frames found, aborting."
    exit 1
fi

# ── 2/2  Encode video ─────────────────────────────────────────
echo "[2/2] Encoding → ${VIDEO} ..."
# shellcheck disable=SC2086
ffmpeg -y \
    -r 30 \
    -i frame.%04d.png \
    -c:v "${FFMPEG_CODEC}" \
    ${FFMPEG_EXTRA_ARGS} \
    "${VIDEO}"

echo ""
echo "Done: ${VIDEO}"