Magical gene / fields and regions

Dorsal Shield

A plate laid over the back from withers to croup, studded with haloed marks - armour rather than a blanket. A third allele carries the same marking worked in greys instead of white - dark where the pale form is light, and the same number of steps.

What it can come out as

OutcomeCarrying
Dorsal ShieldDsh/Dsh · Dsh/Dsc · Dsh/n · Dsh/Dsk
Dorsal Shield, blackDsk/Dsk · Dsk/Dsc · Dsk/n
Dorsal Shield, colouredDsc/Dsc
Wild typeDsc/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 893 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 pairShows asHow often
Dsh/DshDorsal Shield0.004% — 1 in 25,000
Dsh/DskDorsal Shield0.0053% — 1 in 18,751
Dsh/DscDorsal Shield0.0053% — 1 in 18,751
Dsh/nDorsal Shield0.076% — 1 in 1,316
Dsk/DskDorsal Shield, black0.0053% — 1 in 18,751
Dsk/DscDorsal Shield, black0.0053% — 1 in 18,751
Dsk/nDorsal Shield, black0.0053% — 1 in 18,751
Dsc/DscDorsal Shield, coloured0.0053% — 1 in 18,751
n/nWild type99.888%

Its gene carrot

The file

common/src/main/resources/horsegenetics/genes/dorsal_shield.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.

Keyhorsegenetics.dorsal_shield
Phasemagical — it adds signed colour in phase 3, after the pigment has resolved
Priority265 — where it sits in the one (priority, key) paint order
AllelesDsh · Dsk · Dsc · n
Varies per horse5 values drawn once off the expressing allele copy, so a foal that inherits the copy inherits the look
Built fromAXIS, SPOTS, TOWARD

Why it is built this way

Imported from the magic-gene intake, 2026-09-08. The plate is defined in BODY UNITS rather than in part space on purpose: it has to sit at a fixed place on the animal, and a fraction of the barrel would slide as the barrel changes. Every stud layer repeats the same two bands so nothing can escape the plate.

The source used `spread` on a paint op to make the halo. spread is a PIGMENT mask parameter, not an op one; the halo here is the usual big-soft-disc-minus-small-sharp-disc instead.

The black allele is the white one with the light taken out of it, and it sits one rung under white in the dominance series - so every combination that existed before it keeps the outcome it had, and only the pairs carrying Dsk are new. The re-toning is a mapping rather than a repaint: every achromatic target moves into the dark end of the scale keeping its order and its spacing, and every SATURATED one is left alone, because that colour is the gene rather than its lightness.

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.

Dorsal Shield

Two crossed AXIS bands in body units make the plate, so it sits at a fixed place on the horse rather than at a fixed fraction of it - which is what keeps the front and back edges off the shoulder and the croup. Every stud layer carries the same two bands, so nothing escapes the plate.

  1. the shield itself, a plate over the back — AXIS × AXIS, painted with TOWARD
  2. haloed studs set into it — AXIS × AXIS × SPOTS, painted with TOWARD
  3. and the stud at the centre of each — AXIS × AXIS × SPOTS, painted with TOWARD

Dorsal Shield, black

The same marking as the white form with the light taken out of it: the same 2 steps, moved to the dark end of the scale.

  1. the shield itself, a plate over the back — AXIS × AXIS, painted with TOWARD
  2. haloed studs set into it — AXIS × AXIS × SPOTS, painted with TOWARD
  3. and the stud at the centre of each — AXIS × AXIS × SPOTS, painted with TOWARD

Dorsal Shield, coloured

The same plate and studs in a colour the line carries. Fully recessive.

  1. the shield itself, a plate over the back — AXIS × AXIS, painted with TOWARD
  2. haloed studs set into it — AXIS × AXIS × SPOTS, painted with TOWARD
  3. and the stud at the centre of each — AXIS × AXIS × SPOTS, painted with TOWARD

Wild type

No shield.

Paints nothing.