render-sprite

name	render-sprite
description	Render a Spine monster sprite using Godot, convert to 512x512 webp, and save to media/enemies/. Takes a monster display name (e.g. "Ruby Raider (Axe)") or spine folder name (e.g. "axe_ruby_raider").

Render Monster Sprite

Renders a monster's Spine skeleton into a 512x512 transparent webp sprite and places it in media/enemies/.

Output filename = the monster's Key from data/monsters.csv (slug format, e.g. ruby-raider-axe.webp) — NOT the display name. In interactive mode, pass the Key as --display-name= (that flag drives the saved filename).

Arguments

The user provides a monster name — either:

• A display name like Ruby Raider (Axe) or Axebot
• A spine folder name like axe_ruby_raider or axebot

If unclear which monster, list close matches from raw/animations/monsters/ and media/enemies/ and ask.

Step 0: Make sure spine assets exist locally

Monster spine assets live at raw/animations/monsters/{folder_name}/ — but raw/ is periodically regenerated by the beta-pipeline skill with source-code-only includes, so this directory may not exist. Check first; if missing, extract from the game PCK:

"/c/Users/jparr/Downloads/GDRE_tools/gdre_tools.exe" --headless \
  "--recover=/d/Steam/steamapps/common/Slay the Spire 2/SlayTheSpire2.pck" \
  "--output=/c/Users/jparr/Documents/claude/sts2/raw" \
  "--include=res://animations/monsters/*"

(For a single monster, narrow the include to res://animations/monsters/{folder_name}/*.) After extraction, verify the folder contains a matched .skel + .atlas + .png set; if any are stale or in Godot imported format, use the "Extracting Updated Assets During a Patch" section below.

Step 1: Resolve the spine folder name and display name

Monster spine assets live at: raw/animations/monsters/{folder_name}/ Note: some folders have mismatched filenames (e.g. soul_nexus/soulnexus.skel, devoted_sculptor/devoted_scultpor.skel). The GDScript auto-detects .skel and .atlas files independently.

If the user gave a display name, find the matching spine folder by:

• Looking up the monster's Key in data/monsters.csv (Name → Key)
• Checking raw/animations/monsters/ folder names
• The mapping is usually: Display Name -> display_name (lowercase, spaces to underscores)
• Variants like Ruby Raider (Axe) map to axe_ruby_raider (variant prefix + base name)

Resolve BOTH the spine folder name AND the monster's Key (the Key is the output webp filename).

For shared skeletons (e.g. cultists folder with skins coral/slug), use --skin= and --display-name=.

Step 2: Render — choose automatic or interactive mode

Automatic mode

Only use if the user explicitly asks for automatic/non-interactive rendering:

"C:/Users/jparr/Downloads/Godot_v4.6.1-stable_win64.exe/Godot_v4.6.1-stable_win64_console.exe" --path "C:/Users/jparr/Documents/claude/sts2/spine_godot" -- --monster={folder_name} 2>&1

Then convert the output PNG to webp (see Step 3).

Additional flags: --skin=, --output-name=, --anim=, --frames=N, --track1=, --track2=

The automatic renderer uses a SubViewport at 6144x6144 so clipping should not be an issue.

Interactive mode (default)

Opens a Godot window with a slider to scrub through the animation. The user picks a frame and clicks Capture — it auto-converts to webp, saves to media/enemies/, and quits.

"C:/Users/jparr/Downloads/Godot_v4.6.1-stable_win64.exe/Godot_v4.6.1-stable_win64_console.exe" --path "C:/Users/jparr/Documents/claude/sts2/spine_godot" res://interactive.tscn -- --monster={folder_name} "--display-name={key}" 2>&1

(--display-name drives the saved filename — pass the monster's Key, e.g. ruby-raider-axe, so the file lands as media/enemies/{key}.webp.)

Additional flags: --skin=, --track1=, --track2=, --anim=

Interactive mode handles the full pipeline — capture (via 6144x6144 SubViewport), crop, resize, convert to webp, and save to media/enemies/. No manual conversion step needed. After Godot exits, just show the result (Step 4).

Note: The preview window (1920x1080) may show the sprite slightly clipped, but the actual capture uses a 6144x6144 SubViewport so the output will be correct.

Step 3: Convert to 512x512 webp (automatic mode only)

Use Python/Pillow to:

1. Open the rendered PNG (RGBA)
2. Find bounding box of non-transparent pixels (alpha > 0)
3. Crop to content
4. Fit into 512x512 canvas with ~16px padding, preserving aspect ratio (LANCZOS resampling)
5. Center on transparent 512x512 canvas
6. Save as webp (quality=90) to media/enemies/{key}.webp (the monster's Key from data/monsters.csv)

from PIL import Image
import numpy as np

img = Image.open('spine_godot/output/{folder_name}_sprite.png').convert('RGBA')
arr = np.array(img)
alpha = arr[:, :, 3]
rows = np.any(alpha > 0, axis=1)
cols = np.any(alpha > 0, axis=0)
rmin, rmax = np.where(rows)[0][[0, -1]]
cmin, cmax = np.where(cols)[0][[0, -1]]
cropped = img.crop((cmin, rmin, cmax + 1, rmax + 1))
w, h = cropped.size
target = 512
padding = 16
max_dim = target - padding * 2
scale = min(max_dim / w, max_dim / h)
new_w, new_h = int(w * scale), int(h * scale)
resized = cropped.resize((new_w, new_h), Image.LANCZOS)
canvas = Image.new('RGBA', (target, target), (0, 0, 0, 0))
canvas.paste(resized, ((target - new_w) // 2, (target - new_h) // 2))
canvas.save('media/enemies/{key}.webp', 'WEBP', quality=90)

Step 4: Show the result

Read and display the saved webp so the user can visually inspect it.

Multi-Track Monsters

Some monsters need a --track1= overlay animation to look correct. Auto-apply these:

Monster	Folder	--track1=
Soul Nexus	soul_nexus	tracks/writhe
Queen	queen	tracks/writhe
Lagavulin Matriarch	lagavulin_matriarch	_tracks/eyes_closed_loop
Vantom	vantom	_tracks/charged_1
Kaiser Crab	kaiser_crab	left/idle_loop (also needs --track2=right/idle_loop and --anim=body/idle_loop)

Monsters Requiring Non-Default Skins

Some monsters need a specific --skin= to render correctly:

Monster	Folder	--skin=	Notes
Scroll of Biting	scroll_of_biting	skin1	Default skin is just a portal vortex
Cubex Construct	cubex_construct	moss2	Default is just the orb; also needs --anim=attack_loop
Calcified Cultist	cultists	coral	Shared skeleton
Damp Cultist	cultists	slug	Shared skeleton
Toadpole	toadpole	Combined eye1 + pattern1	Needs custom script render_toadpole.gd

Monsters Requiring Non-Default Animations

Monster	Folder	--anim=	Notes
Cubex Construct	cubex_construct	attack_loop	Idle is burrowed (just an orb)
Kaiser Crab	kaiser_crab	body/idle_loop	Idle split across 3 tracks

Monsters Requiring VFX Rendering

These monsters need shader effects or particles to look correct. Use the /render-sprite-vfx skill instead:

Monster	Issue	VFX Script
Waterfall Giant	Water shader + mist particles	render_waterfall.gd
Living Fog (living_smog)	Scrolling smoke shader	render_living_fog.gd
The Lost / The Forgotten	Smoke shader	render_lost_forgotten.gd
Entomancer	Bug swarm particles	render_entomancer.gd
Kin Priest	Fire shader on staff	render_kin_priest.gd
Fogmog	Gas/smoke shader	Not yet created

Static Image Monsters (no Spine data)

Monster	Source
Skulking Colony	raw/images/monsters/skulkling_colomy.png (typo in game files). Convert directly from PNG.

Extracting Updated Assets During a Patch

When rendering sprites after a game patch, the raw .atlas, .skel, and .png files in raw/animations/monsters/ may be outdated. The game's PCK contains updated versions in Godot's imported format at raw/.godot/imported/. All three files must be extracted together as a matched set — mixing old and new files produces broken sprites (wrong dimensions, fragmented pieces).

Imported format conversions:

Source format	Target	How to extract
.spatlas	.atlas	JSON file — parse with json.load(), extract the atlas_data field, write as plain text
.spskel	.skel	Direct copy — the spskel IS the raw skel binary
.ctex	.png	Binary file with GST2 header + embedded WEBP — find RIFF header offset, extract bytes from there, open with PIL

Extraction script:

import json, io
from PIL import Image

monster = "brute_ruby_raider"  # folder name in .godot/imported/

# 1. Atlas: parse JSON, extract atlas_data
with open(f'raw/.godot/imported/{monster}.atlas-HASH.spatlas', 'r') as f:
    atlas_text = json.load(f)['atlas_data']
with open(f'raw/animations/monsters/{folder}/{monster}.atlas', 'w', newline='\n') as f:
    f.write(atlas_text)

# 2. Skel: direct copy
shutil.copy(f'raw/.godot/imported/{monster}.skel-HASH.spskel',
            f'raw/animations/monsters/{folder}/{monster}.skel')

# 3. PNG: extract WEBP from ctex
with open(f'raw/.godot/imported/{monster}.png-HASH.ctex', 'rb') as f:
    data = f.read()
riff_pos = data.find(b'RIFF')
img = Image.open(io.BytesIO(data[riff_pos:]))
img.save(f'raw/animations/monsters/{folder}/{monster}.png')

Verify dimensions match:

After extraction, confirm the PNG dimensions match the atlas size: header line. If they don't, the files are from different versions.

Finding the imported files:

Use glob patterns like raw/.godot/imported/{monster}*.spatlas to find files — the hash in the filename changes between versions. The .import files in the monster's folder also contain the exact imported path.

Paths

• Godot exe: C:/Users/jparr/Downloads/Godot_v4.6.1-stable_win64.exe/Godot_v4.6.1-stable_win64_console.exe
• Spine assets: C:/Users/jparr/Documents/claude/sts2/raw/animations/monsters/
• Godot project: C:/Users/jparr/Documents/claude/sts2/spine_godot/
• Render output: C:/Users/jparr/Documents/claude/sts2/spine_godot/output/
• Final webp: C:/Users/jparr/Documents/claude/sts2/media/enemies/
• Static monster images: C:/Users/jparr/Documents/claude/sts2/raw/images/monsters/