The starburst was three defects, and none of them was the oblique
projection I blamed it on in the last commit. What found them was looking
at the mirror's own render target instead of reasoning about the
composited frame — the water reads it through a fresnel weight, a rippled
UV, a plane-match band and an SSR march that paints over it, so from the
outside a broken mirror and a broken water shader look identical.
WOW_MIRROR_DUMP=1 now writes that target beside the capture. (Bevy's own
save_to_disk cannot: try_into_dynamic knows four 8-bit formats and answers
UnsupportedFormat for Rgba16Float, logging and writing nothing.)
- The oblique row's scale. Replacing the near plane with the water plane
costs the FAR plane: `z >= 0` stops meaning "nearer than CAM_FAR" and
becomes `depth >= a*d`, a plane through the eye tilted by a. Lengyel's
own scale puts that plane exactly through the frustum's far corner, and
the sky dome is pinned just inside the far plane, so it straddled the
boundary and was sliced along its own tessellation. Scale by the
supremum of d/depth over the frustum instead, with 2% of margin.
- The water surface lay ON its own clip plane. This was the starburst and
it was fatal rather than untidy: depth now means "distance above the
plane", so a fragment at d=0 reads z/w=1, the nearest value reverse-Z
has, and beats every other surface in the frame. The mesh is
wave-displaced, so its triangles straddled the plane instead of lying in
it, and each was clipped to a sliver that kept the winning depth.
SURFACE_CLEARANCE lifts the plane a yard: the swell sums to 0.34 and the
probed height answers for the surface under the eye, not this fragment.
- The mirror was stored upside down. A true reflection is what a camera on
the far side sees with its up vector reflected too — an improper basis
no Transform can hold. The honest right-handed camera sees the same
surfaces through the same frustum and stores the image flipped, so the
shader samples 1 - v; that costs no winding flip, so backface culling
stays correct. It read as a lake reflecting the ridge the RIGHT way up.
Measured: Lake Everstill 2.87 -> 3.36 ms mean over 600 frames (+17%), the
Stormwind canal inside the noise, CPU +0.2 to +1.1 ms. It is the first
lane in docs/GRAPHICS.md that spends main thread, so it is a rung of its
own above High and the default stays 2.
Seated as a setting, per the standing rule that no graphics lane hides
behind an env var: waterQuality gains tier 3, the Ultra preset takes it,
and the Advanced Graphics dropdown gains a fourth entry in both locales.
With the lane off, both scenarios are byte-identical to the build before
it — which took two findings of its own:
- The system could not live in Update at all. `&mut Transform` on a camera
is shared with everything that moves anything; declaring it put 59
undeclared orders into Update and tripped the schedule ratchet, which is
what kept this behind an env var. It belongs in PostUpdate with the
skybox and the billboards, after propagation and before visibility,
where it also reads the eye's settled pose instead of a frame-old one.
(The comment blaming ResMut<Assets<Image>> for those 59 was wrong —
dropping the asset handle changed the count by zero.)
- A system that runs and returns on its first line is still not free.
Holding &mut Camera and &mut GlobalTransform for a frame is enough to
change which undeclared orders the executor picks: the canal moved 0.75%
of its pixels by up to 96/255 with the lane switched off. So the whole
system sits behind a run condition rather than an early return — and the
same effect killed a .before(UpdateDirectionalLightCascades) order that
was correct in itself.
PostUpdate's ambiguity ceiling goes 466 -> 495 with the reason (the pairs
are structurally impossible: nothing else in the schedule names the mirror
camera); Update's ratchets down 4973 -> 4952.
Also restores scripts/gates.sh's `where` example, which had gone missing.
Its absence was silent — cargo's error went to /dev/null and `|| true`
made it read as "no install" — so the memo key and the player-tests gate
saw none even when WOW_DATA was set.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SgstFWtn1RxEJ5kVrpgYwn
gromandClaude Opus 5
280c2e886f