Magical gene / magical coat genes

Nacre Saddle

A milky marbled saddle over the back, folded into pale lobes with a thin shifting film picked out along every rim.

What it can come out as

Outcome	Carrying
Nacre	`W/W` · `W/B` · `W/C` · `W/n`
Hematite	`B/B` · `B/C` · `B/n`
Coloured nacre	`C/C`
Wild type	`C/n` · `n/n`

How each one is actually drawn - region by region, and the layers it is built from - is on the coding tab.

Crossing two of them

Finding one

About 1 in 1,786 wild horses is born showing this. That is the whole of the supply: catch one, or make one with the carrot below. Breeds set their own pools and a breed built around this gene will carry it far more often than the wild population does.

Wild pair	Shows as	How often
`W/W`	Nacre	0.002% — 1 in 50,000
`W/B`	Nacre	0.0027% — 1 in 37,495
`W/C`	Nacre	0.0027% — 1 in 37,495
`W/n`	Nacre	0.038% — 1 in 2,632
`B/B`	Hematite	0.0027% — 1 in 37,495
`B/C`	Hematite	0.0027% — 1 in 37,495
`B/n`	Hematite	0.0027% — 1 in 37,495
`C/C`	Coloured nacre	0.0027% — 1 in 37,495
`n/n`	Wild type	99.944%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/nacre_saddle.json — a data-driven gene, not a Java class. It is listed in the index.json beside it and registered by Genes' class initialiser at startup.

Key	`horsegenetics.nacre_saddle`
Phase	magical — it adds signed colour in phase 3, after the pigment has resolved
Priority	150 — where it sits in the one `(priority, key)` paint order
Alleles	`W` · `B` · `C` · `n`
Varies per horse	3 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built from	AXIS, FRACTAL, PARTS, PATCHES, RAMP, TOWARD

Why it is built this way

Four readings of ONE noise field. The three fbm layers are the same seed and scale at rising thresholds, so they nest - each is a smaller core inside the last, which is what gives the folds their depth. The ridged layer is that same field's midpoint surface, so its lines fall exactly on the boundaries the other three are stacked around.

warp 1.0 on every layer, and the same value on every layer. warp pushes the sample point around with a coarser field before any octave is taken, which is the difference between an edge that wobbles and one that wanders. Give one of the four a different warp and it is sampling a different field and the nesting comes apart.

The rim colour is RAMP axis=noise on the film's own seed and scale. It is NOT iridescence and it cannot be: the coat is a texture baked once per horse and no mask or op will ever see a viewer. What it is instead is colour that wanders and pools with no hard edge, which is the honest half of the look. PALETTE would have been wrong here for the opposite reason - it puts hard walls between its lattice cells, and a soap film has no hard edge anywhere.

The PATCHES gate is what keeps this off the whole horse. Without it the marbling tiles every texel of the barrel it is allowed to reach.

Sourced from a traced SVG, but not drawn with the SVG mask. The trace runs to thousands of path commands over hundreds of subpaths, most of it trace noise - well past the point ceiling, which exists to keep a traced photograph out of a gene file, and it would have made the marking identical on every horse. The reference was read for what KIND of shape each element is and rebuilt from field masks. A hand-drawn, low-node version of the source would be worth the SVG mask with its d string verbatim.

Renamed on the way in. It arrived as 'Nacre', which is already a gene here - a coat that breaks into hard-edged plates at gold seams. This one is a marbled saddle with a shifting film along its folds, and the two have nothing in common but the word, so this one took the longer name.

Arrived keyed 'ixora.nacre'. Renamed to the horsegenetics namespace every other gene in the mod uses - the format allows a modder their own, but a gene shipping INSIDE this mod under a second namespace breaks the tooling that builds a key from a slug.

What it paints

Each outcome, described the way the gene file describes it, and then the layers that draw it in the order they are painted. The prose is the part a reader checks a bake against; the list underneath is what the engine actually did.

Nacre

The reference form - a pearl-white marbled saddle with a shifting film along its folds.

the milky ground — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD
the lavender lobes — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD
the film on the rims — PARTS × AXIS × PATCHES × FRACTAL, painted with RAMP
the shadow under the deepest lobes — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD

Hematite

The same folded marbling in graphite and soot.

the milky ground — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD
the lavender lobes — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD
the film on the rims — PARTS × AXIS × PATCHES × FRACTAL, painted with RAMP
the shadow under the deepest lobes — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD

Coloured nacre

Marbling in the line's own colour, palest in the ground and brightest along the rims.

the milky ground — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD
the lavender lobes — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD
the film on the rims — PARTS × AXIS × PATCHES × FRACTAL, painted with RAMP
the shadow under the deepest lobes — PARTS × AXIS × PATCHES × FRACTAL, painted with TOWARD

Wild type

No marking.

Paints nothing.