#!/bin/sh
# Records the test trailer (tools/trailer/trailer.gd) with Godot's Movie
# Maker and encodes it, with a generated music pad under the game's sound:
#
#   tools/trailer/make_trailer.sh        # -> build/Emberwild-trailer.mp4 (+ poster.jpg)
#
# Needs ffmpeg. Takes about a minute: the shots are rendered frame by frame
# at 30 fps whatever the machine's speed, so the result never stutters.

cd "$(dirname "$0")/../.." || exit 1
. tools/godot_env.sh
command -v ffmpeg >/dev/null || { echo "needs ffmpeg (brew install ffmpeg)"; exit 1; }

mkdir -p build/trailer
RAW=build/trailer/raw.avi
OUT=build/Emberwild-trailer.mp4
rm -f "$RAW"
"$GODOT" --path . --resolution 1280x720 --fixed-fps 30 --write-movie "$RAW" \
	--script tools/trailer/trailer.gd -- --no-creatures > build/trailer/render.log 2>&1
if [ ! -f "$RAW" ] || grep -q "SCRIPT ERROR" build/trailer/render.log; then
	echo "recording failed: see build/trailer/render.log"; exit 1
fi

D=$(ffprobe -v error -show_entries format=duration -of default=nw=1:nk=1 "$RAW")
OUT_AT=$(echo "$D - 2.5" | bc)
# (Movie Maker records MJPEG in full-range yuvj420p: Safari and QuickTime
# won't play full-range H.264, so it's converted to standard-range yuv420p.)
# A slow A-minor-ish drone, left and right a little apart, echoed and soft.
PAD="0.06*(sin(2*PI*110*t)+0.7*sin(2*PI*164.8*t)+0.5*sin(2*PI*220*t)+0.35*sin(2*PI*261.6*t)*(0.5+0.5*sin(2*PI*0.08*t)))*(0.75+0.25*sin(2*PI*0.21*t))"
PAD_R="0.06*(sin(2*PI*110.4*t)+0.7*sin(2*PI*165.2*t)+0.5*sin(2*PI*219.6*t)+0.35*sin(2*PI*262*t)*(0.5+0.5*cos(2*PI*0.08*t)))*(0.75+0.25*cos(2*PI*0.21*t))"
ffmpeg -v error -y -i "$RAW" -f lavfi -i "aevalsrc='$PAD|$PAD_R':s=48000:d=$D" \
	-filter_complex "[1:a]lowpass=f=1800,aecho=0.8:0.7:180|340:0.35|0.25,afade=t=in:d=2.5,afade=t=out:st=$OUT_AT:d=2.5[m];[0:a]volume=0.8[g];[g][m]amix=inputs=2:duration=first:normalize=0[a]" \
	-map 0:v -map "[a]" -vf "scale=in_range=pc:out_range=tv,format=yuv420p" -color_range tv \
	-colorspace bt709 -color_primaries bt709 -color_trc bt709 \
	-c:v libx264 -profile:v high -level 4.0 -preset slow -crf 20 -tag:v avc1 \
	-c:a aac -b:a 160k -movflags +faststart "$OUT" || exit 1
# The title, for the download page's poster.
ffmpeg -v error -y -ss 4.5 -i "$OUT" -frames:v 1 -q:v 3 build/trailer/poster.jpg
rm -f "$RAW"
echo "built $OUT ($(du -h "$OUT" | cut -f1 | tr -d ' '), ${D%.*} s) and build/trailer/poster.jpg"