Initial commit — procedural blob-schema reference asset lib v0.1.0

Companion implementation to the design discussion at
sporel-meta/docs/design/2026-05-28-autotile-blob-styles-design.md §9.

Ships the S-V2E2-RM-Blob 14-slot schema in four canonical style
profiles, generated procedurally so the asset lib can be rebuilt
from scratch on any platform with Python 3 + Pillow:

  Styles (14 base slots each, sub-cell-grid layout):
    rectilinear   — crisp 90-degree corners (dungeon walls, retro)
    diagonal_cut  — 45-degree chamfered convex corners (iso-feel)
    organic       — rounded quarter-arc convex corners (water/moss)
    concave       — concave-bite convex corners (frost/web)

  Material variants (single-material atlases, one tinted set each):
    blob_rect_stone   — dark blue-gray (#282C38)
    blob_rect_grass   — mid green       (#4A7838)
    blob_rect_wood    — light brown     (#8B6B3F)

  Multi-material testbench atlas:
    blob_testbench    — 3 materials x 14 slots = 42 tiles in one
                        atlas, for the vagrant-skeleton showcase

Per-style collision.json (axis-aligned rect-list, row+column merged
to minimum form: slot 13 collapses to a single 64x64 rect, slot 4
to a single 32x64 vertical bar, cross variants max 3 rects).
Phase-1: same rectilinear collision shared across all 4 styles,
max 5 px deviation at corners; per-style polygons deferred to
atlas-baker E2.

Reference sheets at docs/reference_sheet_<style>.png show all 14
slots per style in a 7x2 grid with slot index + bitmask + 3x3
neighbour mini-diagram. Color showcase at docs/color_showcase.png
demonstrates that one atlas serves N visual materials via runtime
tint (5 sample colours).

Atlas packer (scripts/atlas_pack.py) is a pure-Python substitute
for sporel-tool-atlas-baker. It produces the Sporel-conformant
4-file atlas set (tiles.atlas.json + tiles.atlas.lock.json +
tiles.diffuse.atlas.png + 1x1 placeholder tiles.height.atlas.png)
with 2 px edge-replicated padding around every tile to prevent
bilinear sampler bleed (sister-tile colours leaking at UV
boundaries — the artefact that caused the green-flicker bug
caught during 0.5.0c integration with vagrant).

Generation pipeline (scripts/bake.sh):
  generate.py        -> 56 base sprites + 4 collision.json
  reference_sheet.py -> 4 reference_sheet PNGs
  color_showcase.py  -> color_showcase.png
  bake_testbench.py  -> 42-tile mixed-material atlas
  bake_singles.py    -> 3 x 14-tile single-material atlases

All output deterministic from the seed scripts (no random state).
.gitignore excludes the baked atlases (assets/atlases/) — those
are reproducible from sources via the bake scripts.

License: CC0 (procedural output, no third-party authorship claim).
Safe for any public-facing build.

Used in production by sporel-module-vagrant-skeleton via the
asset_aliases blob_testbench + blob_rect_stone — see the matching
commit there for the consumer-side integration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,3 @@
+__pycache__/
+*.pyc
+assets/atlases/

LICENSE

@@ -0,0 +1,12 @@
+CC0 1.0 Universal (Public Domain Dedication)
+
+The sprite assets in this lib are procedurally generated from simple
+geometric primitives by the included Python scripts. No copyrightable
+authorship is claimed.
+
+To the extent possible under law, the author has waived all copyright
+and related or neighboring rights to this work.
+
+This work is published from: Germany.
+
+https://creativecommons.org/publicdomain/zero/1.0/

README.md

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+# lib-asset.prototype-blob-geom
+
+Procedurally-generated **reference assets** for the Sporel blob autotile
+scheme (`S-V2E2-RM-Blob`, 14-slot reduction). All sprites are simple
+geometric primitives, drawn programmatically by the bundled Python
+scripts. Intended as a **starting template** for human artists who will
+produce real blob-material sprite sheets (stone, wood, water, ...) that
+slot into the same 14-slot schema.
+
+**Version:** 0.1.0
+**Lib-ID:** `lib-asset.prototype-blob-geom`
+**Role:** asset (pure data, no Lua code)
+**License:** CC0 (procedural output, no authorship claim)
+**Requires:** (none)
+
+## What's in here
+
+```
+prototype-blob-geom/
+├── manifest.lib
+├── LICENSE                      ← CC0
+├── README.md                    ← this file
+├── .gitignore
+├── assets/
+│   └── _sources/
+│       ├── blob_rectilinear/    ← 14 raw 64x64 PNGs + collision.json
+│       ├── blob_diagonal_cut/   ← (same slot count, different visual style)
+│       ├── blob_organic/
+│       └── blob_concave/
+├── scripts/
+│   ├── generate.py              ← procedural writer (sprites + collision)
+│   ├── reference_sheet.py       ← per-style overview
+│   ├── color_showcase.py        ← runtime-tint demo
+│   └── bake.sh                  ← regen everything + atlas-baker for all 4 styles
+└── docs/
+    ├── reference_sheet_rectilinear.png
+    ├── reference_sheet_diagonal_cut.png
+    ├── reference_sheet_organic.png
+    ├── reference_sheet_concave.png
+    └── color_showcase.png
+```
+
+## The 14-slot schema
+
+Each tile reads its 8 neighbour cells. The neighbour-bitmask is clockwise
+from north, LSB-first:
+
+| bit | direction |
+|----:|:---------:|
+| 0   | N         |
+| 1   | NE        |
+| 2   | E         |
+| 3   | SE        |
+| 4   | S         |
+| 5   | SW        |
+| 6   | W         |
+| 7   | NW        |
+
+A diagonal bit only counts if **both** adjacent cardinals are also set
+(blob-gating). After gating and reducing the 47 valid patterns under 90°
+rotation + mirror symmetry, you land on **14 canonical slots**:
+
+| Slot | Name         | Canonical bitmask | Pattern (cardinals + diagonals)        |
+|-----:|--------------|------------------:|----------------------------------------|
+|    0 | isolated     | `0b00000000`      | no neighbours                          |
+|    1 | end          | `0b00000001`      | 1 cardinal (N)                         |
+|    2 | corner_open  | `0b00000101`      | 2 adjacent cardinals (N+E), no diag    |
+|    3 | corner_full  | `0b00000111`      | 2 adjacent cardinals + diagonal (NE)   |
+|    4 | straight     | `0b00010001`      | 2 opposite cardinals (N+S)             |
+|    5 | tee_open     | `0b00010101`      | 3 cardinals (N+E+S), no diags          |
+|    6 | tee_half     | `0b00010111`      | 3 cardinals + 1 diag (NE)              |
+|    7 | tee_full     | `0b00011111`      | 3 cardinals + 2 diags (NE+SE)          |
+|    8 | cross_open   | `0b01010101`      | 4 cardinals, 0 diags                   |
+|    9 | cross_q1     | `0b01010111`      | 4 cardinals + 1 diag                   |
+|   10 | cross_q2adj  | `0b01011111`      | 4 cardinals + 2 adjacent diags         |
+|   11 | cross_q2opp  | `0b01110111`      | 4 cardinals + 2 opposite diags (NE+SW) |
+|   12 | cross_q3     | `0b01111111`      | 4 cardinals + 3 diags                  |
+|   13 | solid        | `0b11111111`      | fully surrounded                       |
+
+At runtime the engine (or atlas-baker, future M.2+) maps every one of
+the 47 raw blob patterns to one of these 14 slots by applying the
+canonical rotation + mirror needed to bring the raw pattern to its
+canonical form. Artists only ever draw the 14 base sprites.
+
+## Styles
+
+All 4 styles share the **same filled-sub-cell mask per slot** (every
+64×64 tile is conceptually a 4×4 grid of 16×16 sub-cells; the
+filled-sub-cell logic is identical across styles). They differ only in
+how **external convex corners** of the material region are rendered:
+
+- The mini neighbour-diagram in the bottom-right of each cell shows
+  which of the 8 surrounding cells share material with the centre cell.
+- Slot 13 (`solid`) is identical across all styles because there are no
+  external convex corners when material continues seamlessly into all 8
+  neighbours.
+- All other slots have at least one external boundary corner, and the
+  styles diverge there.
+
+### Rectilinear
+
+Sharp 90° corners everywhere. Crisp, blocky, pixel-perfect look. Suits
+**dungeon walls, stone floors, retro pixel art**. Easiest to author
+custom art for — every sub-cell is just a filled rectangle.
+
+![Rectilinear reference sheet](docs/reference_sheet_rectilinear.png)
+
+### Diagonal-cut
+
+External convex corners chamfered with a 45° straight line. Gives an
+**architectural, octagonal feel** — slot 0 reads as an octagon, slot 1
+as a "tab", slot 13 stays flat (no boundary). Good for **isometric-feel
+walls, polished stone, art-deco trim**.
+
+![Diagonal-cut reference sheet](docs/reference_sheet_diagonal_cut.png)
+
+### Organic
+
+External convex corners replaced with smooth quarter-arc curves
+(rounded-rectangle treatment). Gives a **bauchy, flowing, blob-like
+feel**. Suits **water, moss, lava, slime, vegetation** — anything that
+should look like it has surface tension.
+
+![Organic reference sheet](docs/reference_sheet_organic.png)
+
+### Concave
+
+External convex corners bitten with an inward quarter-disk. The material
+boundary at corners has **concave indentations**, giving a **filigree,
+crystalline, spider-web feel**. Suits **ice frost, cracks, mycelium,
+arcane growths** — anything that should look like it's reaching out
+fragilely.
+
+![Concave reference sheet](docs/reference_sheet_concave.png)
+
+## Collision
+
+Each style's source directory ships a `collision.json` describing the
+per-slot collision footprint. Geometry is expressed as a list of
+axis-aligned rectangles (row-wise + column-wise merged to the minimum
+useful count). All four styles ship **the same rectilinear collision**;
+for diagonal-cut / organic / concave the visible boundary deviates by
+at most 5 px at convex external corners, which is acceptable for
+typical gameplay collision. Pixel-perfect overrides are a future
+refinement modders can ship per material.
+
+Format (one entry per slot):
+
+```json
+{
+  "schema": "blob-14",
+  "tile_size_px": 64,
+  "shape_kind": "rect_list",
+  "slots": [
+    { "slot": 4, "name": "straight", "bitmask": "0b00010001",
+      "rects": [[16, 0, 32, 64]] },
+    { "slot": 8, "name": "cross_open", "bitmask": "0b01010101",
+      "rects": [[16, 0, 32, 16], [0, 16, 64, 32], [16, 48, 32, 16]] },
+    { "slot": 13, "name": "solid", "bitmask": "0b11111111",
+      "rects": [[0, 0, 64, 64]] }
+  ]
+}
+```
+
+Worst case (cross variants) is 3 rectangles; slot 13 collapses to a
+single 64x64 rect; slot 4 to a single 32x64 vertical bar. The numbers
+are tile-local pixels; the consuming engine translates by the tile's
+world position. Friendly to Box2D / Chipmunk / AABB-tree physics
+backends. Per the design paper §6 the atlas-baker (planned E2) will
+fold these into a sibling `tiles.collision.json` next to the diffuse
+atlas.
+
+## Color variations
+
+The atlases ship in a single neutral stone-gray. Materials don't fork
+the atlas — they **declare a colour tint at the material level**, and
+the engine multiplies the atlas's per-pixel alpha against the tint at
+render time. One geometric atlas, N visual materials:
+
+![Color variations across 5 material tints](docs/color_showcase.png)
+
+This is the production architecture: defining a new material is a
+manifest-level declaration of `{schema, style, tint, collision_policy}`,
+not an asset fork. The bake-pipeline could in principle pre-tint
+atlases for shader-free renderers, but for the M.2+ atlas format the
+tint is applied at draw call time.
+
+Tints used in the showcase above:
+
+| Material | Tint        |
+|----------|-------------|
+| stone    | `#282C38` (default) |
+| grass    | `#4A7838`           |
+| earth    | `#5C3D24`           |
+| wood     | `#8B6B3F`           |
+| ice      | `#7BA8C8`           |
+
+Modders define their own palette in their module manifest.
+
+## How to use this lib
+
+**As a real consumer:** add to module manifest's `deps` and
+`asset_aliases`, choosing which style's atlas you want:
+
+```json
+"deps": [
+    {"id":"lib-asset.prototype-blob-geom","version":"0.1.0"}
+],
+"asset_aliases": {
+    "blob_demo_v1": "lib-asset.prototype-blob-geom"
+}
+```
+
+Maps reference slots by name (`slot_05_tee_open`) or the runtime selects
+them by computed bitmask.
+
+**As a template for new art:** copy the directory, rename to
+`lib-asset.<your-material-name>`, then either:
+
+1. Hand-author 14 PNGs in `_sources/<your-pack>/`, one per slot, using
+   one of the reference sheets above as your style guide; OR
+2. Modify `scripts/generate.py` if you want to keep the procedural
+   approach for a different geometric primitive (e.g. a chunkier
+   blocky style or a more aggressive organic curve).
+
+The atlas-baker (`scripts/bake.sh`) packs your 14 PNGs into the runtime
+atlas format — same pipeline as `prototype-subterrain` and every other
+Sporel asset lib.
+
+## Regenerating
+
+```bash
+python scripts/generate.py            # 14*4 = 56 base sprites + 4 collision.json
+python scripts/reference_sheet.py     # 4 reference sheets
+python scripts/color_showcase.py      # color showcase image
+bash   scripts/bake.sh                # all of the above + atlas-bake all 4 styles
+```
+
+Dependencies: Python 3.10+ with Pillow; Node.js (for atlas-baker).
+
+## References
+
+- Design paper: [`sporel-meta/docs/design/2026-05-28-autotile-blob-styles-design.md`](../../../sporel-meta/docs/design/2026-05-28-autotile-blob-styles-design.md)
+- Boris the Brave, ["Classification of Tilesets"](https://www.boristhebrave.com/2021/11/14/classification-of-tilesets/) — origin of the `S-V2E2-RM-Blob` notation
+- cr31, ["Blob Tileset"](https://www.cr31.co.uk/stagecast/wang/blob.html) — canonical 47-blob reference
+- ADR-0005 (Reserved namespace prefixes — `lib-asset.*` is not reserved, this is a community lib)
+
+## Notes
+
+- **License: CC0.** This lib is safe for any context including
+  public-facing builds, unlike the `toBeDeleted` prototype-asset libs
+  (subterrain, fa-starter) that carry third-party licensing.
+- The output sprites are intentionally simple. Real game-grade art for
+  the same schema should add: bevels, shadow under-tiles, texture noise,
+  edge anti-aliasing, and per-style-profile collision polygons (see
+  the design paper §6).
+- The four styles ship as **parallel atlases**, not as a single
+  combined atlas. A consumer module picks one style per material; mixing
+  styles for the *same* material within one map would create visual
+  incoherence.

assets/_sources/blob_concave/collision.json

@@ -0,0 +1,270 @@
+{
+  "schema": "blob-14",
+  "tile_size_px": 64,
+  "sub_cell_px": 16,
+  "shape_kind": "rect_list",
+  "_note": "Collision matches the rectilinear visual exactly. For diagonal_cut/organic/concave styles, the visible boundary deviates by up to 5 px at convex external corners \u2014 acceptable for typical gameplay collision. Modders needing pixel-perfect physics ship per-style polygon overrides.",
+  "slots": [
+    {
+      "slot": 0,
+      "name": "isolated",
+      "bitmask": "0b00000000",
+      "rects": [
+        [
+          16,
+          16,
+          32,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 1,
+      "name": "end",
+      "bitmask": "0b00000001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 2,
+      "name": "corner_open",
+      "bitmask": "0b00000101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          16,
+          16,
+          48,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 3,
+      "name": "corner_full",
+      "bitmask": "0b00000111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 4,
+      "name": "straight",
+      "bitmask": "0b00010001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 5,
+      "name": "tee_open",
+      "bitmask": "0b00010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          16,
+          16,
+          48,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 6,
+      "name": "tee_half",
+      "bitmask": "0b00010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 7,
+      "name": "tee_full",
+      "bitmask": "0b00011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 8,
+      "name": "cross_open",
+      "bitmask": "0b01010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 9,
+      "name": "cross_q1",
+      "bitmask": "0b01010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 10,
+      "name": "cross_q2adj",
+      "bitmask": "0b01011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 11,
+      "name": "cross_q2opp",
+      "bitmask": "0b01110111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          0,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 12,
+      "name": "cross_q3",
+      "bitmask": "0b01111111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 13,
+      "name": "solid",
+      "bitmask": "0b11111111",
+      "rects": [
+        [
+          0,
+          0,
+          64,
+          64
+        ]
+      ]
+    }
+  ],
+  "style": "concave"
+}

assets/_sources/blob_diagonal_cut/collision.json

@@ -0,0 +1,270 @@
+{
+  "schema": "blob-14",
+  "tile_size_px": 64,
+  "sub_cell_px": 16,
+  "shape_kind": "rect_list",
+  "_note": "Collision matches the rectilinear visual exactly. For diagonal_cut/organic/concave styles, the visible boundary deviates by up to 5 px at convex external corners \u2014 acceptable for typical gameplay collision. Modders needing pixel-perfect physics ship per-style polygon overrides.",
+  "slots": [
+    {
+      "slot": 0,
+      "name": "isolated",
+      "bitmask": "0b00000000",
+      "rects": [
+        [
+          16,
+          16,
+          32,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 1,
+      "name": "end",
+      "bitmask": "0b00000001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 2,
+      "name": "corner_open",
+      "bitmask": "0b00000101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          16,
+          16,
+          48,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 3,
+      "name": "corner_full",
+      "bitmask": "0b00000111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 4,
+      "name": "straight",
+      "bitmask": "0b00010001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 5,
+      "name": "tee_open",
+      "bitmask": "0b00010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          16,
+          16,
+          48,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 6,
+      "name": "tee_half",
+      "bitmask": "0b00010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 7,
+      "name": "tee_full",
+      "bitmask": "0b00011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 8,
+      "name": "cross_open",
+      "bitmask": "0b01010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 9,
+      "name": "cross_q1",
+      "bitmask": "0b01010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 10,
+      "name": "cross_q2adj",
+      "bitmask": "0b01011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 11,
+      "name": "cross_q2opp",
+      "bitmask": "0b01110111",
+      "rects": [
+        [
+          16,
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+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          0,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 12,
+      "name": "cross_q3",
+      "bitmask": "0b01111111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 13,
+      "name": "solid",
+      "bitmask": "0b11111111",
+      "rects": [
+        [
+          0,
+          0,
+          64,
+          64
+        ]
+      ]
+    }
+  ],
+  "style": "diagonal_cut"
+}

assets/_sources/blob_organic/collision.json

@@ -0,0 +1,270 @@
+{
+  "schema": "blob-14",
+  "tile_size_px": 64,
+  "sub_cell_px": 16,
+  "shape_kind": "rect_list",
+  "_note": "Collision matches the rectilinear visual exactly. For diagonal_cut/organic/concave styles, the visible boundary deviates by up to 5 px at convex external corners \u2014 acceptable for typical gameplay collision. Modders needing pixel-perfect physics ship per-style polygon overrides.",
+  "slots": [
+    {
+      "slot": 0,
+      "name": "isolated",
+      "bitmask": "0b00000000",
+      "rects": [
+        [
+          16,
+          16,
+          32,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 1,
+      "name": "end",
+      "bitmask": "0b00000001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 2,
+      "name": "corner_open",
+      "bitmask": "0b00000101",
+      "rects": [
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+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          16,
+          16,
+          48,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 3,
+      "name": "corner_full",
+      "bitmask": "0b00000111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 4,
+      "name": "straight",
+      "bitmask": "0b00010001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 5,
+      "name": "tee_open",
+      "bitmask": "0b00010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
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+          48,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 6,
+      "name": "tee_half",
+      "bitmask": "0b00010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 7,
+      "name": "tee_full",
+      "bitmask": "0b00011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          64
+        ]
+      ]
+    },
+    {
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+      "name": "cross_open",
+      "bitmask": "0b01010101",
+      "rects": [
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+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 9,
+      "name": "cross_q1",
+      "bitmask": "0b01010111",
+      "rects": [
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+          16,
+          0,
+          48,
+          16
+        ],
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+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 10,
+      "name": "cross_q2adj",
+      "bitmask": "0b01011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 11,
+      "name": "cross_q2opp",
+      "bitmask": "0b01110111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          0,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 12,
+      "name": "cross_q3",
+      "bitmask": "0b01111111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 13,
+      "name": "solid",
+      "bitmask": "0b11111111",
+      "rects": [
+        [
+          0,
+          0,
+          64,
+          64
+        ]
+      ]
+    }
+  ],
+  "style": "organic"
+}

assets/_sources/blob_rectilinear/collision.json

@@ -0,0 +1,270 @@
+{
+  "schema": "blob-14",
+  "tile_size_px": 64,
+  "sub_cell_px": 16,
+  "shape_kind": "rect_list",
+  "_note": "Collision matches the rectilinear visual exactly. For diagonal_cut/organic/concave styles, the visible boundary deviates by up to 5 px at convex external corners \u2014 acceptable for typical gameplay collision. Modders needing pixel-perfect physics ship per-style polygon overrides.",
+  "slots": [
+    {
+      "slot": 0,
+      "name": "isolated",
+      "bitmask": "0b00000000",
+      "rects": [
+        [
+          16,
+          16,
+          32,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 1,
+      "name": "end",
+      "bitmask": "0b00000001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 2,
+      "name": "corner_open",
+      "bitmask": "0b00000101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          16,
+          16,
+          48,
+          32
+        ]
+      ]
+    },
+    {
+      "slot": 3,
+      "name": "corner_full",
+      "bitmask": "0b00000111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 4,
+      "name": "straight",
+      "bitmask": "0b00010001",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 5,
+      "name": "tee_open",
+      "bitmask": "0b00010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
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+          16,
+          48,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 6,
+      "name": "tee_half",
+      "bitmask": "0b00010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          48
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 7,
+      "name": "tee_full",
+      "bitmask": "0b00011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          64
+        ]
+      ]
+    },
+    {
+      "slot": 8,
+      "name": "cross_open",
+      "bitmask": "0b01010101",
+      "rects": [
+        [
+          16,
+          0,
+          32,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 9,
+      "name": "cross_q1",
+      "bitmask": "0b01010111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          32,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 10,
+      "name": "cross_q2adj",
+      "bitmask": "0b01011111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          16,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 11,
+      "name": "cross_q2opp",
+      "bitmask": "0b01110111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          32
+        ],
+        [
+          0,
+          48,
+          48,
+          16
+        ]
+      ]
+    },
+    {
+      "slot": 12,
+      "name": "cross_q3",
+      "bitmask": "0b01111111",
+      "rects": [
+        [
+          16,
+          0,
+          48,
+          16
+        ],
+        [
+          0,
+          16,
+          64,
+          48
+        ]
+      ]
+    },
+    {
+      "slot": 13,
+      "name": "solid",
+      "bitmask": "0b11111111",
+      "rects": [
+        [
+          0,
+          0,
+          64,
+          64
+        ]
+      ]
+    }
+  ],
+  "style": "rectilinear"
+}