Updated sprites and pet logic

scripts/stitch_sprite_sheet.sh

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [[ $# -lt 4 || $# -gt 5 ]]; then
+  cat <<'EOF'
+Usage:
+  bash scripts/stitch_sprite_sheet.sh <frames_dir> <cols> <rows> <output_sheet> [prefix]
+
+Example:
+  bash scripts/stitch_sprite_sheet.sh assets/pets/maple/frames 8 9 /tmp/maple-sheet.png maple
+
+Expected input names:
+  <frames_dir>/<prefix>-r01-c01.png
+  <frames_dir>/<prefix>-r01-c02.png
+  ...
+
+Requirements:
+  - ffmpeg
+EOF
+  exit 1
+fi
+
+frames_dir=$1
+cols=$2
+rows=$3
+output_sheet=$4
+prefix=${5:-frame}
+
+if [[ ! -d "$frames_dir" ]]; then
+  echo "error: frames directory not found: $frames_dir" >&2
+  exit 1
+fi
+
+if ! command -v ffmpeg >/dev/null 2>&1; then
+  echo "error: ffmpeg is required" >&2
+  exit 1
+fi
+
+tmp_dir=$(mktemp -d /tmp/hyperpets-stitch.XXXXXX)
+cleanup() {
+  rm -rf "$tmp_dir"
+}
+trap cleanup EXIT
+
+index=0
+for ((row = 1; row <= rows; row++)); do
+  for ((col = 1; col <= cols; col++)); do
+    src="$frames_dir/${prefix}-r$(printf '%02d' "$row")-c$(printf '%02d' "$col").png"
+    if [[ ! -f "$src" ]]; then
+      echo "error: missing frame: $src" >&2
+      exit 1
+    fi
+    cp "$src" "$tmp_dir/$(printf '%04d' "$index").png"
+    index=$(( index + 1 ))
+  done
+done
+
+ffmpeg -loglevel error -y -framerate 1 -i "$tmp_dir/%04d.png" -frames:v 1 -vf "tile=${cols}x${rows}" "$output_sheet"
+
+echo "sheet written: $output_sheet"