Model texture specification

A model surface has two declarations: a contract describing the atlas and charts, and a concrete surface implementing that contract with material and pixels. These textures are distinct from the standalone sprite grammar.

Contract and implementation

Use a concrete complete model surface as a starting point. Widths, heights and origins can consume design values. A contract's chart names, dimensions, coverage and material are checked when the surface is bound; matching spelling alone does not make distinct contracts equal.

Texture recipe fields

Geometry references the required surface port and chart with surface = skin.body;. A cube or plane requires exactly one such binding. The chart's UV footprint must fit its atlas and match its geometry. For a box with dimensions (w, h, d) at one texel per model unit, its net dimensions are (2*w + 2*d, h + d). Do not guess atlas positions or resize a chart independently of its cube. Ashfox does not automatically pack charts.

opaque coverage requires opaque pixels; binary permits transparent/opaque coverage; optional relaxes required coverage. Choose material and coverage together. cutout and double are explicit material choices, not aliases for arbitrary fractional-alpha blending.

Faces, patterns and coverage

Box chart faces use north, south, east, west, up, down. Face-local stamp coordinates start at that face's top-left, rather than the atlas origin. Moving a chart within an atlas preserves face-local coordinates.

A chart or face may contain pattern blotch with paint, scale, density and phase settings. All four are required:

Patterns must precede stamp placement. They control palette pixels, not geometry. Use existing creature surfaces for full recipes with their corresponding contracts.

The recipe coverage = …; form belongs to a flat chart, never a face or box chart. Its unquoted binary digits run row by row and must contain exactly width * height bits. Binary contract coverage requires this mask; opaque coverage cannot contain zero bits. It is a pixel mask, distinct from the contract's opaque|binary|optional enum.

Stamps

Define a stamp once inside the texture recipe. Place it inside a face for a box chart, or directly inside a flat chart. A stamp's pixels is a quoted string of equal-width rows separated by /. . is transparent; lowercase letters or digits name palette mappings. Every used symbol needs exactly one mapping, and unused mappings are rejected.

Fragment inside the same texture recipe:

stamp eye { pixels = "eee/egg/eee"; e = outline; g = iris; }
chart head box {
  origin = (0px, 0px);
  fill = coat;
  face west { stamp eye { anchor = top_left; offset = (1px, 2px); } }
  face east { stamp eye { anchor = top_right; offset = (-1px, 2px); flip = x; } }
}

Placement never scales the stamp. The complete stamp and protection rectangle must fit the face. Center placement that falls on half a texel fails rather than rounding. A flip changes contents, not placement. Later explicit stamps can still overpaint protected pixels. See pixel anchors for resizing and opposite-face examples.