Light

What it does

Crossing two of them

Its gene carrot

Gene key

horsegenetics.light

Priority

160 (magical band)

Alleles

Lthf Ltmn Lteye n

Combinations

10, all carryable — 7 outcomes

Default allele

n

Wild frequency

0.5% per variant allele → ~3% of wild horses glow

Founder draws

1 × nextFloat()

Deterministic

yes — one gold, no per-horse variation

Light level

14 (a torch)

Colour

#ffcf47, the same gold Suntouched uses

The combination table

Where the alleles do not differ

Every glowing combination emits the same torch-strength light. What the alleles decide is where the glow shows, not how much of it there is: a horse with one gold mane lights a stable exactly as well as one with four gold hooves, because in both cases the horse is the light source. Doubling a copy adds nothing either — Lthf/Lthf and Lthf/n are the same horse.

The world light is granted through the ordinary glow verb, so it reuses the trailing minecraft:light block the translator already maintained for Suntouched — with all of that mechanism’s known jank: it lags a gallop, it needs air to sit in, and it is skipped in the horse dimension.

Two halves, in two phases

The gold on the mane and hooves is ordinary phase-3 paint, walked toward the colour so the strands and the hoof shading survive.

The eyes cannot be. CoatRegions.redrawEyes copies them back from the template as the last act of the bake, precisely so that a gene painting a wide white pattern can never blind a horse — so a gene that wants to colour them on purpose has to run after that. That is what the overlay phase is for, and this gene is its first inhabitant.

@Override
public void overlay(AllelePair pair, CoatBuildContext ctx, CoatOverlay out) {
    Set<Region> which = regionsOf(pair);
    if (which.contains(Region.EYES)) {
        out.shadeEyes(GOLD, EYE_STRENGTH);
        out.markEmissiveEyes();
    }
    if (which.contains(Region.MANE)) {
        out.markEmissivePart(Part.MANE);
    }
    if (which.contains(Region.HOOVES)) {
        for (Part leg : CoatRegions.LEGS) {
            out.markEmissiveLowerLeg(leg, HOOF_FRACTION);
        }
    }
}

shadeEyes rather than a flat blend, because an eye is a bright sclera and a dark pupil: a straight lerp turns both into one gold rectangle that stops reading as an eye. Shading scales the target by the texel’s own brightness, so the sclera goes gold and the pupil stays black.

Emissiveness is not a colour

“This texel glows” has no channel in either accumulator, so the overlay phase carries it as its own mask — a boolean per texel, handed to the renderer, which draws exactly those texels a second time at full brightness through EmissiveCoatLayer.

A texel mask rather than a part list is the whole reason this gene can do what Suntouched cannot. Suntouched’s glow effect names body parts, so the finest thing it can light is a whole leg. Light needs to glow four hooves and two eyes, neither of which is a part, and both of which the bake already knows exactly.

It lights a cutie mark too

Light is the first user of CutieMarkContribution: a horse that carries any variant copy here and is also Cutmrk/Cutmrk wears a glowing emblem, drawn full-bright by the render layer.

Same rule as the light itself — where the glow shows is the alleles’ business, whether the horse is a light source is not. And it is the case that makes the modifier hook obviously right rather than merely general: a horse with four burning gold hooves wearing the one dull thing on its body would read as a bug. Nothing else about the emblem moves, so a light horse and its unlit full sibling wear the same mark, lit differently.

Not modelled yet

One gold, no per-horse variation. An epigenetic colour is the obvious extension — mane colour already does exactly that — but it runs straight into a question the game cannot answer: vanilla light has no hue, so a blue-glowing horse would still cast plain white light. That is a real limitation rather than an oversight, and it is why the gene commits to one colour for now.