#3961)

## Release documentation prep for **v26.7.1** (2026-07-02)

29 commits since v26.6.5. Docs-only + version bump — no code behavior
change.

### Version bump 26.6.5 → 26.7.1
The three canonical locations (per `AGENTS.md`):
- `CMakeLists.txt:2` — `project(AetherSDR VERSION 26.7.1)` →
`AETHERSDR_VERSION` (the app's version string)
- `README.md` — Current version line
- `AGENTS.md` — Current version line

### `CHANGELOG.md`
Promoted `[Unreleased]` → **`## [v26.7.1] — 2026-07-02`** in house style
(v-prefix, em-dash, "N commits since…" opener + headline), authored from
all merged PRs and categorized:
- **Added:** 3D stacked-trace spectrum (#3899), 3D dBm scale (#3937),
in-process NVIDIA BNR + AFX download-on-demand (#3902), TX meter
mouse-over readouts (#3936), SWR manual sweep range (#3885), CW sidetone
capture (#3895), KiwiSDR metadata scaffolding (#3898), bridge verbs
(#3920)
- **Changed:** BNR container/NIM backend removed, 60 fps + per-pixel GPU
FFT trace (#3958), FlexLib-sourced model capabilities (#3954/#2177), RX
speaker-latency cut (#3897), Display pane sections (#3935)
- **Fixed:** #3922, #3926, #3941, #3940, #3942, #3921, #3903, #3892,
#3924, #3891, #3890, #3900, #3947
- Fresh empty `[Unreleased]` restored above the release block.
Internal/CI/docs/self-fix PRs (#3931/#3916/#3934/#3929) omitted per
house style.

### `ROADMAP.md`
- Cycle header → "post-v26.7.1"
- NVIDIA BNR removed from **In flight** (shipped this cycle)
- Five v26.7.1 highlights prepended to **Recently shipped**

### `README.md`
- Highlights: GPU spectrum bullet now notes the **per-pixel FFT trace at
up to 60 fps** and the **3D stacked-trace** spectrum mode

### Reviewer notes
- Touches protected paths (`*.md` + `AGENTS.md` Tier-1 +
`CMakeLists.txt`) — needs `@aethersdr/infrastructure` sign-off.
- Tagging `v26.7.1` and cutting the release build are **not** part of
this PR (docs prep only).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

…rry 2D trace on old D3D11 GPUs (#3967). Principle II.

Regression from #3958 (per-pixel GPU FFT trace). initSpectrumPipeline
preferred R32F whenever isTextureFormatSupported(R32F) returned true, but
that predicate only reports create/sample support — NOT linear
filterability. On older Windows GPUs (Intel iGPUs, D3D11 feature level
<= 10.0) R32_FLOAT is sample-supported but not linearly filterable, so the
Linear column sampler silently degrades to point sampling. panscope.frag
then slope-corrects stroke width from dFdx(yTrace)/fwidth() of the sampled
trace; point-sampled columns step between texels, dFdx spikes on every
step, and the perpendicular-distance stroke fattens into the blurred band
the reporter sees.

Fix: use R16F unconditionally — the only float format QRhi guarantees is
linear-filterable on every backend. The stored value is a normalized 0..1
amplitude, for which half-float has ample precision, so this removes the
unreliable hardware-parity fork with no shader change and no visible
quality loss on hardware where R32F was previously filterable. Also drops
the now-dead R32F upload branch in renderGpuFrame.

Honors Principle II (radio is authoritative on live state): the panadapter
must faithfully mirror the FFT the radio reports across all client
hardware, not a GPU-degraded approximation of it.

Blast radius: risk_score=0.272, 19 high-risk affected (top:
MainWindow::MainWindow, MainWindow::wirePanadapter, MainWindow::buildMenuBar).
All are file-level SpectrumWidget callers that construct/wire the widget and
are agnostic to the FFT column texture's internal pixel format; the change is
confined to the GPU render path and reaches none of them behaviorally.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

…filt guard

The pan fps ceiling was raised to 60 on main (perf(gui) aethersdr#3958), but every
constant in the adaptive pipeline is counted in frames and was calibrated
at ~25-30 fps. At 60 fps every dwell/hold/confidence window halves in
wall-clock time and — worse — the frame-counted send throttle
(kSendIntervalFrames=4) allows ~15 filt/s, violating RFC aethersdr#3878 cond. 2
(<= ~8/s).

Frames arriving faster than 25 ms apart are now not accepted (native
~30 fps passes untouched; 60 fps is paced to 30 — the calibration rate —
and the measurement cost halves as a bonus). The gate sits before any
state update, so rejected frames are invisible to every frame counter.
glideToward additionally enforces >= 125 ms between filt sends in
wall-clock, making the RFC bound independent of any fps assumption.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…u-gated smoothing — Principle XI. (#3975)

## Summary

Fixes #3967. Also fixes #3932. Root-caused with per-commit builds
(pre-#3836, post-#3836, 26.7.1-main, this fix) captured minutes apart
against the same live AM broadcast band on a FLEX-8400M:

![4-way
comparison](https://raw.githubusercontent.com/jensenpat/AetherSDR/pr-assets/pan-trace-regression-4way.png)

## The regression chain (two releases, two causes)

**26.6.5 — #3836's unconditional spatial smoothing ("out of focus",
#3932).** `buildFftDisplayTrace`'s 5-tap binomial smooth at a fixed 0.75
blend exists to melt the radio's RBW stair-steps when zoomed in. Applied
to every frame at every span, it rounds narrow carriers (visible height
loss on AM carriers, panel 2) and defocuses the noise floor. **Fix:**
gate the blend on the measured plateau fraction (adjacent equal-pixel
bins). Zoomed-in plateau runs (frac ≳0.65) keep the full blend — #3836's
stair-step fix is preserved; busy wide spans (frac ≲0.35) get zero — the
pre-#3836 crispness returns; the ramp between prevents a visible mode
flip while zooming.

**26.7.1 — #3958's per-pixel stroke ("spiky above and below the line",
the rest of #3967).** The stroke distance was approximated as vertical
distance scaled by a `dFdx`-derived slope — i.e. distance to the
segment's **infinite line**. On steep segments that line passes near the
entire pixel column, so the stroke drew full-height needles above and
below the trace (panel 3), and the fixed ±0.75 px smoothstep band read
as a soft fat stroke at 1× DPI. **Fix:** true endpoint-clamped distance
to the three adjacent polyline segments (4 column samples — matches the
coverage the old geometry quads had), plus falloff parity with the old
`spectrum.frag`: solid to `halfWidth−1`, 1 px fade, 1 px feather annulus
at α 0.22.

Also folds in #3968's R16F-unconditional column format as hardening
(float32 linear filtering is optional on GLES and
`isTextureFormatSupported()` can't detect filterability). Note it could
**not** have caused #3967: the reporter's own About screenshot shows
`D3D11; Intel(R) HD Graphics 520` — feature level 12.1 hardware where
R32F linear filtering is mandatory. With this folded in, #3968 can be
closed.

Not implicated (left untouched, documented for the record): #3836's
`decodeFFT` over-range renormalization only fires on radio/client
`y_pixels` mismatch (transient), and the DPR-scaled
`x_pixels`/`y_pixels` requests are orthogonal to trace sharpness.

## Why our platforms missed it

The #3958 parity checks ran on 2× Retina, where the extra AA softness is
half the logical size and the spike needles read as band activity in
static grabs. The 4-way same-band comparison above is exactly the test
that should have been run: panel 4 (this fix) restores panel 1
(pre-#3836).

## Verification

- 4-way live comparison above (same band, same radio pan, same display
settings; three grabs per build).
- `get panstats 0`: frame prep unchanged at ~121 µs/frame, 58
presents/s, `fftBuildMsPerSec` 0.28 (plateau gate skips the smoothing
copy on wide spans).
- 3D stacked-trace mode, lean mode, line-width 0, heat/solid fill:
unaffected paths re-checked by inspection; the software (non-QRhi-build)
QPainter renderer shares `buildFftDisplayTrace` and picks up the plateau
gate automatically.

## Also on the #3967 thread (separate follow-ups, not in this PR)

- "3D option no longer exists": the 2D/3D combo is the **last row of the
Display panel**, below Background — on short screens (768p laptops) it
clips off the bottom of the panadapter. Needs a scrollable/compacted
Display panel; the option itself ships fine in 26.7.1.
- The 60 fps FFT slider ceiling from #3958 is unrelated to this report
but worth an explicit release-notes mention.

💻 Generated with Claude Code (claude-fable-5 7/2/26) with architecture
by @jensenpat

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>