The first night-sky gate (2026-08-23 screenshot) showed three defects:
glowing beams along the cube-face boundaries (fwidth blowup where
adjacent pixels land on different faces lights every neighbourhood star
solid), diffraction-spiked standouts the user rejects ('that is in a
photo only, not in real sky'), and ellipse-stretched stars from scalar
length(fwidth) sizing at oblique view angles.
One rewrite removes all three: stars now live on a seamless 3D lattice
over the unit sphere (no faces, so no seams by construction), each star
resolved through an exact tangent-plane -> screen-pixel 2x2 solve of
the direction derivatives (perfectly round, true pixel sizing at every
view angle, sharper cores), spikes deleted in favour of a soft round
halo on the bright tiers. Guard test updated to pin the new anchors and
forbid both fwidth-face grids and spikes; sky.frag.spv re-pinned.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
User-directed enhancement ('I want the night sky to look very good'):
retail's star layer is one small texture stretched over a 10-poly dome
cap, so stars smear regardless of source-image quality. With the
Atmospheric render pack active, sky.frag now renders the star layer
(GfxObj 0x010015EF, identical in all 20 Dereth day groups) as a fully
procedural sky computed from the view direction: hash-derived stars on
a cube-face grid in three density tiers plus sparse diffraction-spiked
standouts, sized in SCREEN pixels via derivatives so they stay crisp at
any resolution and FOV, over the user-approved 0.4-1.3% cool mottle
(gen_starfield2.py seed 11, approved 2026-08-23). The draw is forced
additive; the day/night fade rides the star layer's existing retail
lighting product so the schedule matches the authored keyframes. Pack
inactive = retail look byte-untouched.
EnhancedNightSkyRuleTests pins the uParamA gate, the exact star-layer
id, the forced-additive draw, and the pack-runtime wiring; sky shader
SPIR-V recompiled and re-pinned. Hermetic App suite green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
