Magical gene / fields and regions

Nebula Points

Black points - head, muzzle, ears, mane and tail - with a fan of light running up the crest and raking across the barrel. The dominant form glows in the dark; the recessive one is the same pattern in plain pigment.

What it can come out as

Outcome	Carrying
Nebula Points	`Nbg/Nbg` · `Nbg/Nbp` · `Nbg/n`
Nebula Points, pigmented	`Nbp/Nbp`
Wild type	`Nbp/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 3,571 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
`Nbg/Nbg`	Nebula Points	0.001% — 1 in 100,000
`Nbg/Nbp`	Nebula Points	0.004% — 1 in 25,000
`Nbg/n`	Nebula Points	0.019% — 1 in 5,263
`Nbp/Nbp`	Nebula Points, pigmented	0.004% — 1 in 25,000
`n/n`	Wild type	99.972%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/nebula_points.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.nebula_points`
Phase	magical — it adds signed colour in phase 3, after the pigment has resolved
Priority	254 — where it sits in the one `(priority, key)` paint order
Alleles	`Nbg` · `Nbp` · `n`
Varies per horse	2 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built from	AXIS, PARTS, RAMP, STROKES, TOWARD, emissive

Why it is built this way

Imported from the magic-gene intake, 2026-09-08. The points are painted to near-black first and everything else is drawn over them, so the light has something to be light against. The source used a pigment op for that; a magical gene cannot, so it is a paint.

The dominant form is emissive and the recessive one is not. That is the whole difference between the two, and it is the only pair in the mod where the recessive form is the same picture with the light off.

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.

Nebula Points

The points go to black first and everything else is drawn over them, so the light has something to be light against. The fan up the neck is a band on a saw wave, which is what makes it lie along the crest rather than wrap round the throat; the tail is a ramp from near-black at the dock to pale at the tip. All of it is emissive, so a nebula horse is visible at night.

The tail is a RAMP in part space, so it runs dark at the dock to pale at the tip whatever length the tail is. In body space it would have run along the horse instead.

the points taken to black — PARTS, painted with TOWARD
a fan of light up the crest of the neck — AXIS, painted with TOWARD, and it glows
fine strands of it through the mane — STROKES, painted with TOWARD, and it glows
the same, wider and raked, across the barrel — STROKES, painted with TOWARD, and it glows
the tail running from dark at the dock to light at the tip — PARTS, painted with RAMP, and it glows

Nebula Points, pigmented

The same arrangement in ordinary pigment - no glow, and a colour the line carries rather than the bioluminescent blue. Fully recessive.

the points taken to black — PARTS, painted with TOWARD
a fan of light up the crest of the neck — AXIS, painted with TOWARD
fine strands of it through the mane — STROKES, painted with TOWARD
the same, wider and raked, across the barrel — STROKES, painted with TOWARD
the tail running from dark at the dock to light at the tip — PARTS, painted with RAMP

Wild type

No points.

Paints nothing.