#!/bin/bash
# optimise-models.sh — shrink the generated GLBs for the web.
#
# hunyuan3d hands back ~120k triangles and 1024px textures per prop, which is
# ~4MB of download for a cooking pot. Simplified to 10% of the triangles with a
# 0.002 error bound and 512px textures, the same pot is ~800KB and looks
# identical at the distances this game shows it from. The fryer bench alone
# went from a 13MB download to under 3MB.
#
# Idempotence guard: anything already under the threshold is skipped, so a
# second run cannot simplify an already-simplified mesh into mush. Delete the
# file and re-run gen-assets.sh to start from the original.
set -uo pipefail
cd "$(dirname "$0")/.."
MODELS=public/assets/models
SKIP_UNDER=${SKIP_UNDER:-1200000}   # bytes; optimised props land well under this
RATIO=${RATIO:-0.1}
ERROR=${ERROR:-0.002}
TEX=${TEX:-512}
GT="npx --yes @gltf-transform/cli@4.4.2"
TMP=$(mktemp -d)
trap 'rm -rf "$TMP"' EXIT

before=0; after=0; done_n=0; skip_n=0
for f in "$MODELS"/*.glb; do
  [ -e "$f" ] || continue
  name=$(basename "$f")
  sz=$(stat -f%z "$f" 2>/dev/null || stat -c%s "$f")
  before=$((before + sz))
  if [ "$sz" -lt "$SKIP_UNDER" ]; then
    echo "  = $name already lean ($((sz/1024))KB)"
    after=$((after + sz)); skip_n=$((skip_n + 1)); continue
  fi
  if $GT simplify "$f" "$TMP/a.glb" --ratio "$RATIO" --error "$ERROR" >/dev/null 2>&1 \
     && $GT resize "$TMP/a.glb" "$TMP/b.glb" --width "$TEX" --height "$TEX" >/dev/null 2>&1; then
    mv "$TMP/b.glb" "$f"
    nsz=$(stat -f%z "$f" 2>/dev/null || stat -c%s "$f")
    after=$((after + nsz)); done_n=$((done_n + 1))
    echo "  + $name  $((sz/1024))KB → $((nsz/1024))KB"
  else
    echo "  ! $name FAILED — left untouched"
    after=$((after + sz))
  fi
done
echo "----"
echo "optimised $done_n, skipped $skip_n"
echo "total $((before/1048576))MB → $((after/1048576))MB"