v1.1.0

Fixed

• fresco.Rain renders its four parallax depths as four, not three. The layer
  cascade was pinned in raw field units, upstream of the smoothstep contrast curve
  every value passes through before Pass 2. Smoothstep flattens approaching 1, so
  the near and mid layers — 1.00 and 0.72, comfortably apart in the field — both
  landed near the ramp's top and rendered 3.9 L* apart, against the 10-point
  separation the design calls for and the 16.2 its own comment claimed. The
  documented cascade 81.9 / 65.7 / 47.4 / 35.2 was never what reached the screen;
  that was 81.9 / 78.0 / 47.4 / 29.1.
  TestRainLayersSeparateInBrightness and TestRainHeadOutshinesItsTail now measure
  through the curve (rainScreenStopFor), which makes the guard fail on the shipped
  value, and the mid layer's bright moves 0.72 → 0.64 to satisfy it: the rendered
  cascade is now 81.9 / 65.7 / 47.4 / 29.1, separations 16.2 / 18.3 / 18.3. 0.64
  is the centre of the stop-10 plateau rather than an edge of it, so a later palette
  change cannot quietly tip it to a neighbouring stop. Measured on rendered output:
  the mid layer's heads move out of the L* 70–79 band (239 cells → 53) and into
  60–69 (50 → 193), opening the gap under the near layer that the parallax reads
  from. Rendered bytes change by design; determinism, bounds and rain's other
  invariants are untouched.

Changed

• The README demo GIF re-recorded to tour all five variants — it previously
  showed only the pre-campaign four (rain, tunnel, ripple, galaxy) and now includes
  aurora, with every field at the re-art campaign's current look (including galaxy's
  #60 bulge). .github/vhs/demo.tape extends its tour by one variant accordingly.
  Docs/asset only; no code change.

• fresco.Galaxy's bulge grades into the disk instead of saturating into a flat
  bright mass (#60). galBulgeAmp drops 1.0 → 0.60. At 1.0 the pedestal sat near 1.0
  across the inner disk, so the disk it rides on — floor + arm + knot, the knot term
  doubled to galKnotAmp 2.0 in #56 — stacked past 1 and clamp01 flattened the sum:
  2.84% of the pane clipped (val == 1.0, a field-level fact upstream of Pass 2) and
  the core rendered as a solid block of two glyphs. The clamp was discarding real
  structure, not a smooth saturated field — across the clipped cells the pre-clamp
  bulge + disk spans 1.02..2.75 — so dropping the pedestal is what lets it show,
  rather than making room for structure never computed. At 0.60 clipping falls to 1.36%
  (the residue is sparse knot peaks, not a block) and the nucleus's local glyph
  contrast — |centre − mean(8-ring)| in ramp steps, the flat-mass metric — rises
  0.13 → 0.43, while the core stays the field's brightest region (core colour-stop
  density 11.5 against the mid-disk's 6.1). A soft-knee was measured and rejected:
  removing the clamp without dropping the pedestal compresses the 1.02..2.75 spread
  into a band near 1.0 the glyph ramp cannot resolve, and the nucleus goes flatter
  (contrast 0.008). galBulgeAmp was settled by rendering {0.50, 0.55, 0.60, 0.65}
  in colour and mono and looking: 0.65 fills the nucleus back toward the old solid look,
  0.50 shrinks it to a dim dot that no longer reads as the bright core.
  TestSplashGalaxyRendersABrightCoreAndDimmingArms gains a core-structure floor
  (nucleus glyph contrast > 0.25, placed between the measured flat 0.13 and graded
  0.43): its coreLit > 0.9 and coreDens > midDens were both satisfied by the flat
  block they were meant to guard and so could not have caught this. Rendered bytes
  change by design; determinism, bounds and purity hold.

• The galaxy band tests measure against the renderer's own length scale (#61). The
  radial ruler was computed two ways — renderField took the vertical term as
  max(cyFocal, h-1-cyFocal), galaxy_test.go took cyFocal — which differ by one on
  an even-height pane (29 vs 30 at 240×60; on odd heights the two are equal), so the
  test's rho ran ~0.7% large — the raw vertical term differs ~3%, diluted through the
  hypotenuse by the dominant half-width — and slid every band boundary inward. Both
  now call one splashMaxD(w, h, focalRow) helper (rain's and ripple's band tests
  too), so they cannot diverge again. The knot entry
  below quotes its arm-annulus bead figures on the pre-#61 ruler and the pre-#60 bulge
  (118.5 per 1000, ridge/gas 213.8 / 19.7, 10.9×); on the corrected ruler and the
  shipped field they are 135.5 per 1000, and — taking ridges as arm ≥ 0.75 and gas
  as arm ≤ 0.30 (the raised-cosine spiral phase, before the turbulence lift) across
  the 0.35 ≤ rho < 0.60 annulus, over frames 0/30/60 at 240×60 — 243.8 / 26.8, a
  9.1× ratio (the lower bulge lifts the inner-annulus gas cells, so gas beads rise a
  little more than ridge). No rendered-byte change.

• fresco.Tunnel retuned for a warmer, textured corridor. Its lumRange moves
  from 1 to 0.75, so the ring texture takes the glyph-density ramp
  (o → O → 0 → @) and reads as a tactile, receding surface rather than a flat
  field of a single @; and the depth hue now relaxes to a warm base
  (tunHueBase) where the sampling-rate mip leaves the sweep unresolved — the near
  field and, on a real pane, most of the view — so the corridor reads as a warm
  interior receding into the cool cyan rings that survive out where the sweep
  resolves, instead of a uniform purple-blue wash. The field's brightness (the fog
  depth cue) and its mip/angular-seam guarantees are unchanged; only the Pass-2
  luminance split and the hue's unresolved fallback moved. Rendered bytes change by
  design; determinism, bounds, and the tunnel's invariants still hold.

• fresco.Galaxy caught mid-turn. Its rigid pattern rotation galRotSpd doubles
  (1.0 → 2.0) so the spiral's turn — the roster's weakest motion — is plainly alive
  within a second or two of viewing while staying stately rather than spinning (phase
  is the field's only time term, so the per-frame step is far below any strobe). The
  arm turbulence is also raised (galTurbAmp 0.62 → 0.72, galKnotThr 0.68 → 0.63,
  galKnotAmp 0.70 → 0.85), which adds grain and lifts the brightest turbulence peaks
  into local highlights. The texture stays additive-on-peaks, so it opens no holes; the
  bright core still outshines the disk, the arm mip/anisotropy and core-finite
  guarantees are unchanged, and hue still moves without touching brightness. Rendered
  bytes change by design; determinism, bounds, and the galaxy's invariants still hold.

  An earlier draft of this entry claimed the knots "read as distinct bright beads
  strung along filamentary arms". Measured against galKnotAmp = 0, that overstates
  what the change does. The knot term is not inert — it produces 12× the local maxima
  (73 against 6 across three frames, at ≥8 L* over their neighbours) — but those
  maxima land in the bright core and the faint outskirts, not on the arms: per 1000
  lit cells the arm annulus carries 0.0 and 3.1 beads against 14.9 at the core
  and 12.3 further out, the lowest density in the field. In the glyph-density channel
  they do nothing measurable at any radius (mean glyph weight 9.24 against 9.22 in
  the arms). That draft went on to blame saturation — "the arms already sit at 8.4–9.2
  of 11 on the ramp, so an additive term there clips instead of studding" — and that
  mechanism is false too: re-measured at 240×60 over three frames, the arm annulus
  clips (val == 1.0) on 11 of 14,712 cells, 0.07%, and sits at a mean val of
  0.40 of 1.0, so there was headroom where the claim said there was none. Clipping
  in the field is real but lives at the bulge, not the arms (508 cells, 1.2% of the
  pane). Both the mean-glyph figure and the local-maxima distribution above are also
  single-channel readings taken before the instrument was sound. The
  actual cause is measured in the entry below. The rotation half of this entry is
  unaffected.

• fresco.Galaxy's arms are actually studded now, and the reason the previous
  attempt could not have worked is a spatial-frequency one rather than a gain or a
  headroom one. The knots were gated on splashGalaxyTurbulence, an fBm carrying 47%
  of its energy at a period of 7.7 columns and 74% at 3.8 columns or wider, so the term
  brightened a region four to eight cells across — and a brightened region reads as a
  brighter arm, not as a knot. Measured against the term switched off, only 40% of
  the brightest decile of such brightenings survived subtracting its own eight
  neighbours (27.6% across every cell the term brightened at all): the blob's own skirt
  lifted the background it had to stand above.

  A bigger galKnotAmp could only buy that back by blowing the arms out. Swept on the
  old term, arm beads per 1000 lit go 13.1 → 32.2 → 50.8 → 70.4 → 84.7 at
  galKnotAmp 0.85 / 2 / 4 / 8 / 16, so gain alone does eventually clear this PR's own
  guard (TestSplashGalaxyArmsCarryKnots floors at 40) — the flat "no amount of gain
  could have fixed it" an earlier draft of this entry claimed is false. What it costs
  is the field: arm clipping rises 0.07% → 1.90% → 6.36% across that sweep, against
  118.5 beads at 1.50% clipping from the lattice below. Four times the gain for
  half the beads at worse clipping is the case for changing the term rather than
  tuning it.

  So the knots now ride their own high-frequency lattice (galKnotFreq 0.9,
  galKnotPeak 0.5, galKnotAmp 0.85 → 2.0), sampled in screen cells rather than
  in-plane ones — the in-plane axes are anisotropic by cellAspect/cos(galInc) = 2.17,
  so a frequency compact enough to read horizontally packs past Nyquist vertically. The
  turbulence now only gates them, softly (galKnotGas 0.35), because multiplying two
  sparse gates together starves the count faster than amplitude pays it back. Its gate
  also normalises against galTurbCeil 0.93 — the fBm's measured maximum over 4.7M
  samples — instead of the 1.0 it never reaches; the old divisor 1-galKnotThr assumed
  a peak of 1.0, so over that same sweep the gate topped out at 0.82 rather than 1
  and averaged 0.157 over the 15.9% of samples where it fired at all (0.025 across
  the whole sweep).

  lumRange drops 0.75 → 0.60 alongside, because dens = lit^(1-lumRange) was
  spending the glyph ramp where it could not be seen: at 0.75 no measurable cell
  anywhere rendered below glyph 4 of 11, so the disk used only the ramp's top two
  thirds. At 0.60 the floor drops to glyph 2 and the faint disk grades · : ; +
  into dark space rather than ending abruptly. Holding the knots fixed, that is worth
  45.8 → 76.9 beads per 1000 lit cells across the measurable pane, and 73.5 →
  118.5 inside the arm annulus. It stops at 0.60 rather than lower because 0.45
  collapses the outskirts into the scatter of . and · the luminance channel exists
  to prevent. Settled by
  rendering {0.35, 0.45, 0.60, 0.75} in colour and mono and looking; galKnotFreq
  the same way over {0.5, 0.7, 0.9, 1.3} (0.5 merged the beads into clumps, 1.3
  degenerated into single-cell grain).

  Measured at 240×60 over three frames, beads per 1000 lit cells — cells standing a
  full glyph step above their eight neighbours — go from 5.6 to 118.5 in the
  arm annulus, and the arms carry the field's highest density (core 17.6,
  outskirts 67.2) rather than its lowest. They land on the arms rather than between
  them: taking the ridges as arm ≥ 0.75 and the inter-arm gas as arm ≤ 0.30 within
  that annulus, 213.8 per 1000 against 19.7, a 10.9× ratio.
  TestSplashGalaxyArmsCarryKnots is the new guard for this and fails on the
  pre-change field; every previous galaxy assertion is a band mean and could not have.
  Rendered bytes change by design; determinism, bounds, purity, the arm
  mip/anisotropy and core-finite guarantees all still hold.

• fresco.Ripple retuned to make its interference pattern — the field's jewel —
  read, in three moves. Its crest amplitude rippleAmp drops (0.85 → 0.65) to open
  headroom under the clamp: at 0.85 the render curve already sent a lone crest to
  within a hair of a doubled one, so the bright nodes where rings add did not stand
  out; the lower value opens that gap and lights the constructive lattice against the
  lone rings (the pool dims a little, the trade that keeps the fixed stars from
  outshining the water). Its carrier rippleCyc rises (1.5 → 1.8), deepening the
  packet's trough (41% → 54% of the crest) so the cancellation nodes where two rings
  meet out of phase darken and |sum| reads as a pattern rather than a stack of
  circles, and giving each drop a second, fainter concentric wavefront — the train a
  real drop throws. And the ring's hue is rebased onto its visible life
  (rippleHueOpen): a drop is a filled disc for its first ~38% and only an expanding
  ring after, so the raw age-hue spent its whole warm end on the disc and left the ring
  the cool 60% of the gradient — rebasing hands the expanding ring the whole
  warm→cool journey, so a ring's age reads across its life. Separately the starfield —
  ripple's alone among the variants — is thinned (starThreshold 0.986 → 0.992) from a
  competing sparkle layer into a faint still sky the rings sit in front of. The |sum|
  interference, the exact 3×3×2 spawn window, the compact-support packet, and purity
  are unchanged. Rendered bytes change by design; determinism, bounds, and ripple's
  invariants still hold.

• fresco.Rain retuned so its two signatures — the bright head and the depth —
  land, in two coordinated moves. Its head lobe tightens (rainHeadR 4.5 → 2.9),
  which is a fix as much as a retune: rainTailAmp buys a ~28-point L* gap under
  the head, but a 4.5-unit lobe reached 1.68 rows and sat in that gap itself, so the
  cell one row behind a head landed at L* 71.8 against the head's 81.9 — a 10-point
  step, and a head that rendered as a two-cell blob rather than an edge. At 2.9
  that step is 34.5 and the darkness the tail had already paid for finally reaches
  the head; because the lobe is symmetric, it also cuts the glow ahead of a falling
  head from ~1.7 rows to under a cell. And a fourth parallax depth is added
  (rainLayers [3] → [4], with rainDensity 0.62 → 0.54 so four compounding
  layers do not fill the pane), because three left a hole in the middle of the
  brightness histogram and the eye sorted them into "near" and "far" instead of
  reading a recession; the four now land at L* 81.9 / 65.7 / 47.4 / 35.2, and the
  room for the extra layer came from the darker field the first move opens. The
  anti-blink guarantee is untouched — the ramp's top stop is reachable only from the
  rainHeadFlat plateau, and the rendered count of top-stop cells is unchanged
  across the whole rainHeadR sweep. lumRange stays at 1: rain's render branch
  consumes only the luminance channel and discards the density one, so lowering it
  would not hand the tail a glyph ramp at all — it would merely lift the whole field
  and close the head/tail gap, which the rendered sweep confirmed. The stream-train
  purity, the fall speed, the tail-length window, and the bespoke luminance ramp are
  unchanged. Rendered bytes change by design; determinism, bounds, and rain's
  invariants still hold.