grok-galgame-sprites

name	grok-galgame-sprites
description	Generate consistency-locked Galgame full-body standing sprites with solid

Grok Galgame Sprites

Grok-side workflow for transparent Galgame standing sprites. Built from the real pipeline used on maid_princess and similar runs.

This is not the Codex generate-galgame-sprite-diffs skill. That skill targets WebGAL eye/mouth forced composites and browser lip-sync. This skill does not produce runtime blink or mouth-sync parts. It stops at approved transparent full-body mothers (reference, poses, expressions).

What this skill produces

• reference_normal — identity lock, full-body, closed mouth, open eyes
• several pose bases — distinct neutral stances, still closed mouth / open eyes
• several expression mothers — face emotion on a mapped pose; body stays locked
• all as transparent PNG on a shared 1024×1536 canvas
• contact sheets + simple inventory/README for download

What this skill does NOT produce

• WebGAL eyes_close / eyes_half / mouth_half_open / mouth_open runtime frames
• local replacement parts for blink or lip-sync
• GIF demos of speaking or blinking
• forced local composite (outside_mask_changed_pixels pipeline)

If the user later asks for blink/mouth differential, say clearly that Grok Imagine full-body regenerations drift enough that local eye/mouth paste is unreliable, and keep those requests out of this skill’s default path.

Hard invariants

1. Key color is always solid #FF00FF. No gradients. No auto key picker. User preference is fixed magenta so cutout is deterministic.
2. Canvas is always 1024×1536 with about 6% margin after normalize.
3. Generate on chroma, cut out after. Never treat a gray or photo background as final.
4. One identity lock. Primary reference wins for age, proportions, face, costume, palette, style. Do not adult-ify or genericize a petite/chibi design.
5. Review gates. Stop for approval after reference, after pose group, after expression group. Do not silently advance.

Tooling

• Image generation / edit: Grok Imagine via edit_image (preferred for identity-preserving pose and expression edits) or generate_image when no source exists yet.
• Cutout / normalize / validate / rekey: scripts/sprite_tools.py in this skill directory.

Resolve SKILL_DIR to this SKILL.md folder.

python "$SKILL_DIR/scripts/sprite_tools.py" cutout \
  <chroma-source> <out-transparent.png> \
  --key-color '#FF00FF' --scope all \
  --soft-matte --despill --auto-refine \
  --auto-refine-max-alpha-loss 0.025

python "$SKILL_DIR/scripts/sprite_tools.py" normalize \
  <transparent.png> <final-1024x1536.png> \
  --canvas 1024x1536 --margin-percent 6

python "$SKILL_DIR/scripts/sprite_tools.py" validate \
  <final.png> --expect-size 1024x1536 --key-color '#FF00FF'

python "$SKILL_DIR/scripts/sprite_tools.py" rekey \
  <transparent.png> <chroma-out.png> --key-color '#FF00FF'

If residual magenta fringe remains on fine hair or lace after a normal cutout, run a stronger pass (higher opaque distance / extra despill) and compare alpha area loss. Keep the stronger result only when fringe is gone and silhouette is not eaten.

Always sample the actual border of a generated chroma image. Grok Imagine sometimes returns a near-magenta that is not exact #FF00FF; pass the sampled color into cutout when needed.

Stage flow

BASE_PENDING → BASE_REVIEW
POSES_PENDING → POSES_REVIEW
EXPRESSIONS_PENDING → EXPRESSIONS_REVIEW
COMPLETE (export transparent pack)

1. Reference (reference_normal)

If the user supplies a front character sheet:

1. Use edit_image to replace only the background with pure solid #FF00FF. Do not redesign the character.
2. Cut out → normalize → validate.
3. Show transparent result and stop for approval.

If there is no image, generate one full-body front stance on pure #FF00FF with a tight identity prompt, then the same cutout path.

Reject age-up, leg stretch, costume rewrite, or face drift.

2. Pose bases

Default lean set (override only when the user asks):

id	intent
idle	relaxed asymmetrical conversational stance
side	clear three-quarter lean (~25–35° body), face still readable, eyes to viewer
reserved	inward, hands gathered, narrower stance

Optional extras used successfully in production: note (holding a small paper and reading), welcome (open greeting hands), guide (side-lean with one hand raised as if presenting).

Rules:

• Generate each pose independently from the approved reference chroma via edit_image. Never chain pose → pose.
• Keep eyes open, mouth closed (faint closed-lip curve OK).
• Poses must differ in hands, shoulders, torso axis, hips, and feet — not only one hand.
• After cutout + normalize, build a contact sheet. Stop at POSES_REVIEW.

Prompt pattern (keep identity locked):

Precise full-body edit. Same character identity, age, proportions, costume, colors, pure solid #FF00FF background.
Change ONLY the pose to: <pose description>.
Eyes open, mouth fully closed. No other redesign.

3. Expression mothers

Map expressions to an approved pose (example defaults):

expression	from pose	notes
laugh	side	may keep closed eyes as part of the expression
thinking	side	may keep closed eyes
angry	idle
sad	reserved
surprised	side
shy	reserved

Rules:

• Edit from the mapped pose’s chroma, not from another expression.
• Change face only (and blush / highlights if needed). Body, hands, costume stay fixed.
• After cutout, prefer reusing the pose’s normalize transform when alignment is already good; otherwise normalize independently and check silhouette.
• Contact sheet of all expressions → EXPRESSIONS_REVIEW.

Prompt pattern:

Precise face-only edit. Same body, pose, hands, costume, pure solid #FF00FF background.
Change ONLY the facial expression to: <emotion>.
Do not move the body or redesign clothing.

4. Export pack

At COMPLETE, assemble a download folder:

<slug>_sprites/
  chroma/          # optional #FF00FF sources
  cutout/          # final transparent 1024×1536 PNGs
  previews/        # contact sheets
  README.md
  inventory.json

README should list every sprite, key color, canvas size, and state that runtime blink/mouth is out of scope for this pack.

Cutout quality checklist

Before approving any mother:

• Hair tips and flyaways are not chopped into magenta blocks
• Pale clothing / white apron has no pink halo
• Enclosed gaps (between arm and body, under skirt) are transparent where they should be
• No large residual key fringe on the outline
• Validate reports residual key edge near zero when possible

If fringe remains, run the stronger cutout variant and show a before/after edge zoom. Keep stronger only when it clearly helps.

Practical notes from production

• Gray or non-chroma backgrounds on source images cause color shift (e.g. blonde → pink). Always force #FF00FF first with edit_image, then cut out.
• Grok Imagine 2.0 is strong at identity-preserving pose and expression edits when the prompt is strict and the input is already chroma.
• Full-body regenerations always drift a few pixels. That is acceptable for whole-sprite mothers; it is why this skill refuses local eye/mouth differential.
• Prefer parallel edit_image calls for a pose group or expression group when the tool allows, then cut out sequentially.

Relation to the Codex skill

topic	Codex generate-galgame-sprite-diffs	This skill
generator	Codex / GPT image path	Grok Imagine 2.0 (edit_image / generate_image)
key color	auto choose + preferred	fixed #FF00FF
poses + expressions	yes	yes
WebGAL eye/mouth runtime	yes (forced local composite)	no
blink / lip-sync parts	yes	no
deliverable focus	figures + parts + runtime compositor	transparent mothers + contact sheets

Keep both skills in the repo. Route users who only need standing sprites and expressions to this one. Route WebGAL mouth-sync / blink packaging to the Codex skill when that environment is available.