git:20260912.a38072a to git:20260913.dd45fc1

27 added, 29 removed. Audit A to A.

---

name: sprite-atlas

- description: Full 2D image set for a game. Sheets, tiles, UI, portraits, projectiles. Image 2.5 generates plates. Boxes stay in other skills.

+ description: Use when sprite sheets need slicing, stable pivots, texture packing or engine metadata, or when an imported animation jitters, bleeds between cells or loses attachments.

---

# Sprite atlas

- Generate one family per image. Style lock `art-bible`. Timing `pixel-animation`. Paint `sprite-skin`. VFX plates `vfx-generate`. Hurtboxes never come from the PNG.

+ Own **packing and import**, not image inventory. [Sprite catalog](../sprite-catalog/SKILL.md) owns required image families; [pixel-animation](../pixel-animation/SKILL.md) owns playback and gameplay frame mapping. Keep the existing family's intent when older callers ask this skill to generate art; route generation before packing.

- ## Families (generate these; do not invent a folder per pose)

+ ## Modes

- | Family | Typical plates |

+ | Mode | Output |

|---|---|

- | char-cycle | idle, walk, run, jump, fall, land, crouch, climb, swim, dash |

- | combat-pose | attack-light, attack-heavy, hurt, death, block, parry, charge |

- | facing | 4-dir or 8-dir of the same cycle; east may be a flip |

- | companion | same cycle, slimmer set |

- | enemy | idle, walk, telegraph, attack, hurt, death |

- | projectile | bullet, arrow, magic bolt, bomb, plus empty shell |

- | weapon-overlay | sword/gun layer aligned to sockets |

- | tileset | floor, wall, platform, slope, water, hazard, door, ladder |

- | prop | chest, crate, torch, plant, breakable |

- | pickup | coin, heart, key, ammo, weapon drop |

- | ui-kit | button 4-state, panel, frame, cursor, slider |

- | hud-icon | hp, mp, stamina, status, item, quest pin |

- | portrait | bust, talk blink, emotion row |

- | shadow | blob or contact shadow, separate layer |

- | vehicle | hull + wheel or mount cycle |

- | background | sky, parallax far/mid, fog plate |

- | vfx | route to vfx-generate columns |

+ | grid-slice | uniform source cells and explicit empty-cell handling |

+ | trimmed-pack | varying trimmed regions with original geometry preserved |

+ | tileset | tile IDs, margin/separation and terrain metadata |

+ | ui-kit | regions plus nine-slice borders and widget states |

- ## Image 2.5 contract

+ Legacy families char-cycle, portrait, projectile, prop, combat-pose, facing, companion, enemy, weapon-overlay, pickup, hud-icon, shadow, vehicle and background remain inventory requests; resolve a packing mode afterwards. VFX generation goes to [vfx-generate](../../assets/vfx-generate/SKILL.md).

- 1. Name the artefact: "N-frame sprite sheet in one row" or "tileset grid 8x8".

- 2. Even cell size. Same pivot. Flat chroma or transparent.

- 3. Neutral pose first. Do not bake VFX into walk.

- 4. No readable UI words unless this family is ui-kit and the words are specified.

- 5. One facing per sheet unless asked for a turnaround.

+ ## Procedure

- Accept: a walker sheet slices without re-aligning feet. Combat poses do not change hitstop (`juice-vfx`).

+ 1. Inspect real image dimensions, alpha, cell layout, facing and target loader/version. An attractive generated sheet is not necessarily an exact grid. Reject or repair malformed cells explicitly; never silently crop a weapon or foot.

+ 2. Measure pivot/attachment positions against the untrimmed source coordinate system. Publish axis direction and pixels-per-unit. If trimmed or rotated, export the transform back to the source; disable rotation for loaders that cannot represent it.

+ 3. Export each region's ID, `source_size`, packed rectangle, `trim_offset`, `pivot`, rotation, socket offsets and `duration_ms`. Preserve stable IDs across repacks. A zero-alpha cell may be an intentional timing frame, not removable waste.

+ 4. Choose padding/extrusion, filtering, mipmaps, page size and compression for the actual renderer. A fixed one-pixel rule is not sufficient for all mip levels. Report alpha convention and test against light and dark backgrounds.

+ 5. Import the metadata and replay the animation. Map artwork durations onto the authored simulation timeline; never change active frames to fit a PNG. Hitboxes and hurtboxes stay authored gameplay data.

+ ## Output

+ Atlas images, frame/animation metadata, source manifest mapping, packing settings, version/rights record, measured alignment deviations and an import result. Unsupported loader features are blocked, not guessed. Generation and packing scripts must not overwrite source art without explicit permission.

+ ## Accept

+ Replay idle/walk/attack with overlays for source pivot and sockets; trimming must not move them. Repack and verify saved IDs still resolve. Test empty frames, rotated imports, edges at minification and missing-region fallback. A missing attachment must not create invisible invulnerability.

+ ## Reference

+ [Godot TileSet atlas properties](https://docs.godotengine.org/en/stable/tutorials/2d/using_tilesets.html) describe a concrete loader's margins, separation and padding. Inspect the target version rather than copying its settings to every engine.