Rotation (user-directed): the procedural starfield rotates once per
Dereth day (~2 real hours - constellations visibly wheel through a
night) about a celestial pole ~41 deg above the northern horizon, plus
dayOfYear/360 of seasonal drift so the 360-day year changes the night
sky. One SkyParams float (272-byte block, layout test re-pinned)
carries dayFraction + dayOfYear/360 from the world clock; sky.frag
applies a Rodrigues rotation to the sample direction so stars and
mottle turn together. Impossible with retail's static stretched layer.
Fade rework (the 2026-08-23 two-screenshot gate finding): the
per-vertex vTint signal carried the sun-facing product and blanked
stars across the entire twilight half of the sky. The fade now reads
the UNIFORM ambient term - identical star visibility in every compass
direction, same dusk-to-dawn schedule - with one deliberate exception:
a thin suppression band hugging the low sky toward the sun's azimuth
while the sun term is strong, so stars still wash out inside the
actual twilight glow.
Guards updated (rotation anchor, uniform-fade anchor, 272-byte layout);
both sky SPIR-V hashes re-pinned.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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>
Two April stand-ins, neither registered, met at the horizon from altitude as
a hard line between the dome's rim and the fog-coloured clear:
1. sky.frag fogged every non-additive sky layer with a 0.2 floor. Retail's
GameSky::Draw @0x00506FF0 disables fixed-function fog around the whole
sky draw unless an AdminEnvirons fog override is active (SetFFFogEnable(
LScape::m_override_enabled ? 1 : 0)); additive layers stay unfogged via
SetFFFogAlphaDisabled(1) at D3DPolyRender::SetSurface 0x59c882. The sky
pass now sets ApplyFog only for (override active && !additive), with no
floor.
2. WorldRenderFrameBuilder overwrote the authored fog range with one derived
from the streaming window (538..2189 m always). Retail sets FOGSTART/
FOGEND straight from the keyframe's MinWorldFog/MaxWorldFog
(SkyDesc::GetWorldFog @0x00500CE0 -> SetFFFogProperties @0x005A2F70) with
no draw-distance scaling; zfar is a constant 4000 m. The builder now
leaves SceneLightingUbo.Build's values alone; ACDREAM_FOG_START_MULT /
_END_MULT are deleted from RuntimeOptions.
Guards: SkyFogRuleTests (source-level, the sky renderer has no hermetic
harness); sky.frag.spv re-pinned in VulkanShaderManifestTests with the
reason. Research note 2026-04-23-sky-fog.md carries a correction banner.
App hermetic 6,070/0, Core 4,707/0 (Release). Owner look gate owed: night
and rain fog are now retail's shorter authored ranges.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
