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fix(sky): A7 — correct sun-vector magnitude (ambient + sun were ~32% too bright)

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Outdoor lighting was ~32% too bright (washed-out, weak shading). Live cdb on
retail (SmartBox::SetWorldAmbientLight + SkyDesc::GetLighting + LScape::sunlight,
binary matches refs/acclient.pdb) pinned it: at the SAME game time + DayGroup,
acdream's ambient COLOR matched retail exactly (the purple is correct, authored
per-time-of-day in the sky dat) but the LEVEL was 0.607 vs retail's 0.459.

level = AmbBright + 0.2·|sunVec|, both AmbBright=0.40, so acdream's |sunVec|≈1.06
vs retail's ≈0.30. Retail's LScape::sunlight read live = (0.2238, ~0, 0.00352),
magnitude 0.224 = DirBright, y≈0.

RetailSunVector had `y = cos(P)` (≈1) — the raw PRE-transform value SkyDesc::
GetLighting writes to arg5 (0x00500ac9), before LScape::set_sky_position's
world transform. acdream ported the un-transformed vector, so the y=cos(P)≈1
term inflated |sunVec| to ~1.06. That magnitude feeds BOTH the ambient boost
(SkyKeyframe.AmbientColor) AND the sun colour (SkyKeyframe.SunColor =
DirColor×|sunVec|), over-brightening the whole scene (terrain, objects, sky)
~30% and also pointing the sun the wrong way.

Fix: RetailSunVector = DirBright × (cos(P)·sin(H), cos(P)·cos(H), sin(P)) — the
world-space spherical form LScape::sunlight actually holds; |sunVec| == DirBright
for all H/P. After: acdream ambient (0.353,0.176,0.449) vs retail (0.360,0.180,
0.459) — within ~2%, user-confirmed "better outside". Sun direction also corrected
(was pointing ~North from the bad y term).

Tests updated to the cdb-verified values (the prior tests pinned the inflated
magnitude). 18/18 sky tests green. reference-retail-ambient-values memory updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Erik 2026-06-18 15:08:52 +02:00
parent 4345e77d62
commit 57c11358b6
3 changed files with 73 additions and 56 deletions
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17
tests/AcDream.Core.Tests/World/SkyDescLoaderTests.cs
View file

@ -100,22 +100,23 @@ public sealed class SkyDescLoaderTests
{
// The loader stores DirColor and DirBright RAW. The SunColor property
// composes them via |sunVec| per retail's UpdateLightsInternal at
// 0x59b57c (decomp 424118) — the diffuse magnitude is sqrt(x²+y²+z²)
// where the sun vector is built from heading/pitch/brightness with
// Y unscaled by brightness (decomp 261352).
// 0x59b57c (decomp 424118) — diffuse = DirColor × |LScape::sunlight|.
// cdb-verified (reference-retail-ambient-values): |LScape::sunlight| ==
// DirBright for every keyframe (world-space spherical vector, magnitude
// DirBright·sqrt(cos²P+sin²P) = DirBright).
//
// For this region: H=180°, P=70°, B=1.5
// sunVec = (sin(180)*1.5*cos(70), cos(70), 1.5*sin(70))
// = (0, 0.342, 1.410)
// |sunVec| = sqrt(0 + 0.117 + 1.988) = 1.4509
// sunVec = 1.5 × (cos(70)·sin(180), cos(70)·cos(180), sin(70))
// = (0, -0.513, 1.410)
// |sunVec| = sqrt(0 + 0.263 + 1.988) = 1.500 (= DirBright)
// DirColor.X = 200/255 = 0.7843
// SunColor.X = 0.7843 × 1.4509 = 1.138
// SunColor.X = 0.7843 × 1.500 = 1.1765
var region = MakeRegion(dirBright: 1.5f, rBgrOrder: 200);
var loaded = SkyDescLoader.LoadFromRegion(region);
Assert.NotNull(loaded);
var kf = loaded!.DayGroups[0].SkyTimes[0].Keyframe;
Assert.InRange(kf.SunColor.X, 1.13f, 1.15f);
Assert.InRange(kf.SunColor.X, 1.17f, 1.18f);
}
[Fact]