enhancements

Author: danja

TODO.md

@@ -15,8 +15,6 @@ Open items only. Finished work is recorded in the plugin docs and `MISTAKES.md`.
   either. Low urgency, since `include/downspout/test_assert.h` already makes a lost
   `-UNDEBUG` a compile error. Touches root glue and ~36 plugin CMake files, so it needs
   approval and a full test run.
-* **Add `-Wall -Wextra` to `downspout-project-options`** and clear the remaining noise
-  plugin by plugin so it cannot regress. Needs approval and a full 62-suite run.
 
 ## Session state (found 2026-10-06)
 
@@ -54,12 +52,9 @@ Standalone `g++ -std=c++20 -Wall -Wextra -fsyntax-only` over `plugins/*/src/*.cp
 `-Iplugins/generative-common/include` or conductor, drift, ghost, guardian, harmonic-atlas
 and others will not compile). No `-Wswitch` warnings remain. What was left on purpose:
 
-* `cadence` (2) and `drumgen` (1): `-Wclass-memaccess` on `memset` of structs with default
-  member initialisers. Safe in practice. One wrinkle to decide: `cadence_clear_progression`
-  zeroes `ChordSlot`, whose `velocity` defaults to 96, so a cleared slot has velocity 0
-  rather than the constructed default.
-* `mnemosyne`, `mosaic`: `-Wmisleading-indentation`. The cores are dense one-line
-  statements; reformatting is churn, not a fix.
+* `cadence` and `drumgen` `memset` calls are `void*`-cast, so they no longer warn. (Re-swept
+  2026-10-10: zero warnings across `plugins/*/src/*.cpp`.) `cadence_clear_progression` now
+  resets slots to `ChordSlot{}` (velocity 96) instead of zeroing; cadence tests pass.
 * `campione` loader: the `smpl` loop end is inclusive in the WAV spec, but the engine wraps at
   `position >= loopEnd`, so the last loop sample is skipped (one frame). Changing it means
   adjusting load, save and the engine together; decide whether it is worth it. (The ignored
@@ -85,6 +80,12 @@ and others will not compile). No `-Wswitch` warnings remain. What was left on pu
   cutoff position linearly (t = 0.5 is a notch at the cutoff), and it only reshapes the
   forward filter, not the Scream feedback high-pass.
 
+* **Damiano Linked/Split stereo** is in and tested (per-channel Mode, Drive, Tone, Folds; CC Drive and
+  CC Shape per channel on a shared CC channel; see `plugins/damiano/docs/porting-notes.md`). Not yet
+  auditioned in a host: try Split with Soft left and Fuzz right, and two Drift lanes on CC Drive / CC
+  Drive R. Verify an old project (pre-split state) loads Linked. Open: "shape" is the stepped waveshaper
+  mode; a continuous shape (asymmetry/bias) would be new DSP. Tone and Folds are not CC-controlled.
+
 * `voxmod`: host validation in REAPER still pending.
 * `keyframe`: the leash diagram is static at unity rates because drift is genuinely ~0 there;
   a splice halo was added so it reads live during crossfades. If it still reads dead at
@@ -99,8 +100,8 @@ Remaining:
 * **Verify in a host (REAPER):** load, play notes, filter an audio track, save/reopen state.
   Nothing has been listened to. Also confirm the host accepts an instrument with audio inputs.
 * Listen to drum levels (normalised per hit, consistent at ~0.15); check voice-stealing clicks.
-* GM Program mode warms only the last requested voice; other voices build on first note
-  (~1.9 ms). Warm several if this is audible.
+* GM Program mode now queues a warm-up per Program Change (last 8 voices); host-check that
+  switching programs on several channels no longer glitches on first notes. Offline-tested only.
 * `scripts/capture-plugin-screenshots.sh` captures the real desktop if `DISPLAY` is set
   (see `MISTAKES.md`). Make it always use Xvfb. Shared script, needs approval.
 * Catalogue screenshot shows Synth mode (filter dimmed); consider a Synth + Filter capture.
@@ -155,11 +156,11 @@ Remaining:
   shared (`include/downspout/cellular_automaton.hpp`, tested in `tests/cellular_automaton_tests.cpp`) and used
   by `polymeter`, `drumgen` and `xoxolo`. Open: xoxolo's grid shows the programmed pattern, not the
   evolved row now playing.
-* **Magneto look and feel:** Retune, Sprout and Markov use a plugin-local `MagnetoKit.hpp` (identical
-  copies in `plugins/retune/src/dpf/`, `plugins/sprout/src/dpf/` and `plugins/markov/src/dpf/`) built on
-  `downspout/look_and_feel.hpp`, matching Pratt and Magneto. Moving it to a shared header
-  would remove the duplicate but is shared code and needs approval. Older generator
-  plugins still use `GenerativePanelUI` (mosaic, polymeter, etc.); restyle if wanted.
+* **Magneto look and feel:** the kit is now shared, `include/downspout/dpf/MagnetoKit.hpp`, used by
+  Retune, Sprout, Markov and Damiano (new hooks: overridable `sendValue()` for plugins that carry
+  values as state, `setValue()` and `setDim()`). Older generator plugins still use
+  `GenerativePanelUI` (mosaic, polymeter, etc.); restyle if wanted. Retune, Sprout and Markov were
+  rebuilt against the shared header but not re-screenshotted; confirm they look unchanged.
 * **Gravity** is in `harmonic-atlas`. `cadence` (learned harmony) has not had it; its progression
   model is different, so decide whether a gravity bias on the learned transitions makes sense.
 * **Atlas voice-leading** is local to `harmonic-atlas`. Listen to it; the chords sit low (around
@@ -172,8 +173,10 @@ Remaining:
   not pass incoming MIDI through; the editor does not move while a CC drives a control.
 * **Conductor awareness** was added to `lifeform`, `luma`, `polymeter` and `xoxolo` (off by default; not yet auditioned
   in a host). `counterpointer` and `cadence` followed (the CC mapping is a tested pure function,
-  `applyConductorCc`, in their core-types headers; CC 24 relearns). Still without it among the generators:
-  `arpgen`, `mnemosyne` (only Novelty and a seed re-roll would fit, and its core takes parameters const, so it needs wrapper-level handling), `m-mix`, `sidecar` (its wrapper is tangled up with the server path),
+  `applyConductorCc`, in their core-types headers; CC 24 relearns). `arpgen` followed (CC 21 Density -> Octaves,
+  CC 22 Energy -> Rate; `applyConductorCc` in `arpgen_core.hpp`, tested; screenshot recaptured; not yet auditioned
+  in a host). `m-mix` followed (CC 21 Density -> Open Bias, CC 22 Energy -> Maintain inverted; tested; UI slider added and
+  the window made taller because its sixth slider row had been hidden under the toggles). Still without it among the generators: `mnemosyne` (only Novelty and a seed re-roll would fit, and its core takes parameters const, so it needs wrapper-level handling), `sidecar` (its wrapper is tangled up with the server path),
   `tuney-vst`. Worth adding where a density or energy knob exists.
 * Later candidate: chord-graph walker. A shared voice-leading helper in
   generative-common is only worth it if a second plugin needs it (shared code, needs approval).

docs/midi-mapping.md

@@ -211,6 +211,34 @@ Cadence gains one parameter, **Conductor Ch** (`conductor_ch`, 0-16, default 0 =
 
 CC 20 (Scene) is not mapped.
 
+## Arpgen mapping
+
+Arpgen gains one parameter, **Conductor Ch** (`conductor_ch`, 0-16, default 0 = off), appended after
+its status outputs. The CCs set the controls directly, as if you had moved them, so a later change on
+the panel or from host automation takes over until the next CC arrives.
+
+| CC | Conductor name | Arpgen control | Notes |
+|----|---------------|----------------|-------|
+| 21 | Density | `octaves` | 1-4, four equal steps over 0-127 |
+| 22 | Energy | `rate` | 1/4, 1/8, 1/8T, 1/16, 1/16T, 1/32: six equal steps, slow to fast |
+
+CC 20 (Scene), 23 (Mutation) and 24 (Reset) are not mapped. With **Pass Input** on, the Conductor's CCs
+are passed through with the rest of the input.
+
+## M-Mix mapping
+
+M-Mix gains one parameter, **Conductor Ch** (`conductor_ch`, 0-16, default 0 = off), appended after
+Mute. As with Arpgen the CCs move the controls directly, so a later panel or automation change takes
+over until the next CC.
+
+| CC | Conductor name | M-Mix control | Notes |
+|----|---------------|---------------|-------|
+| 21 | Density | `bias` (Open Bias) | 0-100%: the chance a gate change opens, so higher density passes more notes |
+| 22 | Energy | `maintain`, inverted | 100% to 0%: higher energy holds the gate state less often, so it changes more |
+
+CC 20 (Scene), 23 (Mutation) and 24 (Reset) are not mapped. Non-note MIDI already passes through
+M-Mix, so the Conductor's CCs continue downstream.
+
 ## Markov mapping
 
 Markov has one parameter for Conductor reception, **Conductor ch** (`conductor_ch`, 0-16, default 0 = off).

docs/pages/_products/arpgen.md

@@ -21,6 +21,10 @@ Scale mode uses held notes as register anchors for in-key runs, triads, or
 sevenths. Both modes support one to four octaves, velocity following, gate
 control, straight and triplet rates, and endpoint-safe alternating patterns.
 
+### Conductor
+
+Set **Conductor Ch** to the channel Conductor sends on (it defaults to 16; 0 is off) and Conductor shapes the arpeggio over the song: CC 21 (Density) sets Octaves from 1 to 4 and CC 22 (Energy) steps Rate from 1/4 up to 1/32. The CCs move the controls as if you had, so you can still override them by hand.
+
 ### Status
 
 The portable core, deterministic tests, VST3 wrapper, and custom UI are in

docs/pages/_products/damiano.md

@@ -6,7 +6,7 @@ kind: Audio effect
 category: processor
 role: Stereo distortion
 screenshot: /assets/plugins/damiano.png
-summary: Six-mode stereo distortion with drive, tone shelf, wet/dry mix, output gain, and real-time MIDI CC override of drive from Drift or any CC source.
+summary: Six-mode stereo distortion with drive, tone shelf, wet/dry mix and output gain. Linked or Split left/right processing for a binaural effect, with Drift CC control of each channel's drive and shape.
 ---
 
 ## Opinion
@@ -37,8 +37,12 @@ Damiano is a stereo distortion with six selectable waveshaping modes. Each mode
 | Folds       | 1–8            | 2       | Cascade depth in Wavefold mode; greyed out in other modes          |
 | Mix         | 0–100 %        | 100 %   | Wet/dry blend                                                      |
 | Output Gain | −24 to +24 dB  | 0 dB    | Post-distortion level trim                                         |
-| CC Number   | off / 1–127    | off     | Which MIDI CC number overrides Drive in real time                  |
-| CC Channel  | 1–16           | 1       | MIDI channel to listen on                                          |
+| CC Drive    | off / 1–127    | off     | MIDI CC number that overrides Drive in real time (left, or both when Linked) |
+| CC Shape    | off / 1–127    | off     | MIDI CC number that selects the Mode in six steps (left, or both when Linked) |
+| CC Channel  | 1–16           | 1       | MIDI channel to listen on (shared)                                 |
+| Stereo      | Linked / Split | Linked  | Split enables the right-channel settings below                     |
+| Right Mode, Drive, Tone, Folds | as left | Tanh, 2, 50 %, 2 | Used only in Split                         |
+| CC Drive R, CC Shape R | off / 1–127 | off | Right-channel CC numbers (Split only)                         |
 
 ### Tone shelf
 
@@ -50,10 +54,19 @@ When CC Number is set to anything other than off, incoming MIDI CC messages on t
 
 This is designed to work directly with the Drift MIDI modulator. Route Drift's MIDI output to Damiano's MIDI input and assign the same CC number in both.
 
+### Stereo: Linked and Split
+
+The **Stereo** switch chooses how the two channels are processed.
+
+- **Linked** (default): the right channel mirrors the left settings. This is the behaviour of earlier versions, and old sessions load as Linked.
+- **Split**: the right channel has its own Mode, Drive, Tone and Folds, so each ear can be distorted differently. Fed the same signal on both sides, a Split setting such as Soft on the left and Fuzz on the right widens and detunes the image. Mix, Output Gain and the CC channel stay shared.
+
+Each channel has its own **CC Drive** and **CC Shape** numbers (off / 1-127), all read on the shared CC Channel. CC Shape selects the waveshaper mode: the 0-127 range is divided into six equal steps (Soft, Tanh, Fuzz, Overdrive, Tube, Wavefold). In Linked mode the left CC numbers drive both channels and the right ones are ignored. Point two Drift lanes at the two CC Drive numbers to modulate the channels independently; a slow lane on one and a fast lane on the other gives a moving binaural beat.
+
 ### Wavefold notes
 
 The triangle wavefolder applies the fold transfer function in series, re-driving the signal at each stage. High Drive combined with many Folds produces dense harmonic content that can sound noise-like at extreme settings — this is the intended character of the mode rather than an artefact. For cleaner folding tones, keep Drive below 5 and Folds at 2–4.
 
 ### Status
 
-All six distortion modes and the MIDI CC drive link are functional and tested. A fresh screenshot is needed.
+All six distortion modes, the MIDI CC drive link and the Linked/Split stereo processing are functional and covered by core tests (channel independence, CC mapping, state round-trip, pre-split state loading). The screenshot shows Split mode. Not yet auditioned in a host.

docs/pages/_products/m-mix.md

@@ -19,6 +19,10 @@ M-Mix processes incoming MIDI notes rather than audio. Notes pass only when the
 current probability and Euclidean gates are open, making it useful for rhythmic
 note thinning, comping variation, and transport-locked MIDI movement.
 
+### Conductor
+
+Set **Conductor Ch** to the channel Conductor sends on (it defaults to 16; 0 is off). CC 21 (Density) sets Open Bias, so denser sections let more notes through, and CC 22 (Energy) sets Maintain inverted, so more energetic sections change the gate more often. The CCs move the sliders as if you had, so you can still override them by hand.
+
 ### Status
 
 Functional but awaiting review in practical application.

docs/pages/assets/plugins/arpgen.png

@@ -35,7 +35,7 @@ prose and example chains see `docs/summary.md`; for scale tables see `docs/scale
   by default so Drift needs no configuration. Conductor emits CC 20-24 on channel 16
   (Scene, Density, Energy, Mutation, Reset); bassgen, drumgen, ground, melgen, worms, bubbles,
   floozy, harmonic-atlas, sprout, lifeform, luma, polymeter, xoxolo, markov, counterpointer
-  and cadence listen through a **Conductor Ch**
+  cadence, arpgen and m-mix listen through a **Conductor Ch**
   parameter (0 = off). Mixgen drives T-Mix with CC
   20-27 (strips 1-8), Loopdelay with CC 30/31, Lightverb with CC 32/33; CC 19 claims or
   releases the producer bus. Details: `docs/midi-mapping.md`,
@@ -285,7 +285,8 @@ alters the host graph. Targets: bassgen, drumgen, ground, worms, bubbles.
 Transport-synced arpeggiator. **Chord** mode captures incoming chord slices; **Scale**
 mode derives scale runs, triads or sevenths from held register anchors. Rates quarter
 through thirty-second, straight and triplet; one to four octaves; up, down and alternating
-orders. Latch and capture state are internal. Requires transport.
+orders. Latch and capture state are internal. Requires transport. **Conductor Ch** (0 = off):
+CC 21 Density sets Octaves (1-4), CC 22 Energy sets Rate (1/4 up to 1/32).
 
 ### cadence
 Transport-aware harmoniser and comping generator that learns harmony from incoming MIDI
@@ -306,7 +307,8 @@ Persistent motif state; requires transport.
 
 ### m-mix
 Transport-aware MIDI gate combining probabilistic P-Mix-style transitions with E-Mix-style
-Euclidean blocks: removes or passes notes before they reach an instrument.
+Euclidean blocks: removes or passes notes before they reach an instrument. **Conductor Ch**
+(0 = off): CC 21 Density sets Open Bias, CC 22 Energy sets Maintain inverted (busier gating).
 
 ### retune
 MIDI effect that retunes a note stream to a Scala `.scl` scale. For each held note it
@@ -496,8 +498,11 @@ selectable channel; CC 0 disables) so Drift drives it directly.
 ### damiano
 Six-mode stereo distortion (Soft, Tanh, Fuzz, Overdrive, Tube, Wavefold) with Drive 1-10,
 Tone (one-pole high shelf before the shaper, about 3 kHz, 50% = flat), Folds 1-8
-(Wavefold only), Mix and Output Gain (+-24 dB). One selectable CC number overrides Drive
-in real time.
+(Wavefold only), Mix and Output Gain (+-24 dB). **Stereo Linked/Split** (default Linked,
+identical to before): Split gives the right channel its own Mode, Drive, Tone and Folds
+for a binaural effect. Selectable CC numbers (all on one CC channel, 0 = off): CC Drive and
+CC Shape (waveshaper mode in six steps) for the left or both channels, and CC Drive R and CC Shape R
+for the right channel (Split only), so two Drift lanes can modulate the channels independently.
 
 ### skream
 Scream filter: input through an ADAA2 anti-aliased tanh saturator and an SVF low-pass,

docs/pages/assets/plugins/damiano.png

@@ -3,8 +3,13 @@
 // Magneto-style panel toolkit for a NanoVG DPF UI: flat surface panels with
 // accent-coloured headers, horizontal bar sliders, stepper and segmented
 // controls, and a dark/light theme toggle, all drawn from downspout/look_and_feel.hpp.
-// Plugin-local on purpose (shared code needs approval); retune, sprout and markov keep
-// identical copies of this file.
+// Shared by retune, sprout, markov and damiano. This header depends on DPF, which is why
+// it lives under downspout/dpf/ rather than beside the portable headers.
+//
+// A plugin derives from MagnetoUI, calls beginFrame()/drawHeader()/drawPanel() and the
+// draw* controls from onNanoDisplay(), and handles buttons in onAction(). By default a
+// control change goes to the host with setParameterValue(); override sendValue() when a
+// plugin carries its values some other way (damiano sends state keys).
 
 #include "DistrhoUI.hpp"
 
@@ -77,6 +82,9 @@ class MagnetoUI : public UI {
     // A button, stepper half or segment was pressed. `id` is the caller's own number.
     virtual void onAction(int id) = 0;
 
+    // Delivers a value the user just set. Default: a host parameter change.
+    virtual void sendValue(const std::uint32_t parameter, const float v) { setParameterValue(parameter, v); }
+
     bool onMouse(const MouseEvent& ev) override
     {
         if (ev.button != 1)
@@ -141,10 +149,23 @@ class MagnetoUI : public UI {
         if (r.integer)
             v = std::round(v);
         values_[parameter] = v;
-        setParameterValue(parameter, v);
+        sendValue(parameter, v);
         repaint();
     }
 
+    // Updates the displayed value without sending it anywhere (for state or host echoes).
+    void setValue(const std::uint32_t parameter, const float v)
+    {
+        if (parameter < count_) {
+            values_[parameter] = v;
+            repaint();
+        }
+    }
+
+    // Fades everything drawn until the next call, to show a control or panel is inactive.
+    // Controls drawn while dimmed still respond to the mouse.
+    void setDim(const bool dim) { globalAlpha(dim ? 0.38f : 1.0f); }
+
     // ── Frame ───────────────────────────────────────────────────────────────
 
     void beginFrame()