S5 Tier-1: zoned keymap editor + performance-map playback/persistence

Zone editor in the IPlugView LICE surface, zoned resolution built off-thread into the
LoadedInstrument keymap with Tier-0 fallback, performance map in VST3 component state
with v1 back-compat. Pure resolve/build/serialize + geometry with CTest coverage.

src/vst/editor_geometry.cpp

@@ -75,4 +75,90 @@ int sampleRowHitTest(const EditorLayout& layout, int rowCount, int x, int y) {
     return index;
 }
 
+// --- Keymap editor -----------------------------------------------------------
+
+KeymapEditorLayout layoutKeymapEditor(int w, int h) {
+    KeymapEditorLayout out;
+    out.base = layoutEditor(w, h);
+    const Rect& canvas = out.base.canvas;
+
+    // Split the canvas vertically: the left column is the bank-sample list, the right
+    // column (1/kZonePanelFraction of the width) is the zone panel. Guard tiny widths so
+    // the split point never crosses the canvas edges.
+    const int canvasW = std::max(0, canvas.width());
+    const int splitW = canvasW / kZonePanelFraction;          // width of the zone panel
+    const int splitX = std::max(canvas.left, canvas.right - splitW);
+
+    out.sampleList = Rect{canvas.left, canvas.top, splitX, canvas.bottom};
+    out.zonePanel = Rect{splitX, canvas.top, canvas.right, canvas.bottom};
+
+    // "Add Zone" button spans the top of the zone panel, clamped to its height.
+    const int addH = std::min(kAddZoneHeight, std::max(0, out.zonePanel.height()));
+    out.addZoneButton =
+        Rect{out.zonePanel.left, out.zonePanel.top, out.zonePanel.right,
+             out.zonePanel.top + addH};
+
+    // Zone rows stack below the button.
+    out.zoneRowArea = Rect{out.zonePanel.left, out.addZoneButton.bottom,
+                           out.zonePanel.right, out.zonePanel.bottom};
+    return out;
+}
+
+Rect keymapSampleRowRect(const KeymapEditorLayout& layout, int index) {
+    if (index < 0) return Rect{};
+    const int top = layout.sampleList.top + index * kSampleRowHeight;
+    return Rect{layout.sampleList.left, top, layout.sampleList.right,
+                top + kSampleRowHeight};
+}
+
+int keymapSampleRowHitTest(const KeymapEditorLayout& layout, int rowCount, int x, int y) {
+    if (rowCount <= 0) return -1;
+    const Rect& list = layout.sampleList;
+    if (x < list.left || x >= list.right) return -1;
+    if (y < list.top || y >= list.bottom) return -1;
+    const int index = (y - list.top) / kSampleRowHeight;
+    if (index < 0 || index >= rowCount) return -1;
+    const Rect r = keymapSampleRowRect(layout, index);
+    if (y >= r.bottom) return -1;
+    return index;
+}
+
+Rect zoneRowRect(const KeymapEditorLayout& layout, int index) {
+    if (index < 0) return Rect{};
+    const int top = layout.zoneRowArea.top + index * kZoneRowHeight;
+    return Rect{layout.zoneRowArea.left, top, layout.zoneRowArea.right,
+                top + kZoneRowHeight};
+}
+
+ZoneHit zoneHitTest(const KeymapEditorLayout& layout, int zoneCount, int x, int y) {
+    if (zoneCount <= 0) return ZoneHit{};
+    const Rect& area = layout.zoneRowArea;
+    if (x < area.left || x >= area.right) return ZoneHit{};
+    if (y < area.top || y >= area.bottom) return ZoneHit{};
+    const int index = (y - area.top) / kZoneRowHeight;
+    if (index < 0 || index >= zoneCount) return ZoneHit{};
+    const Rect row = zoneRowRect(layout, index);
+    if (y >= row.bottom) return ZoneHit{};
+
+    // Seven mini-buttons pinned to the right edge, right-to-left:
+    //   delete, root+, root-, high+, high-, low+, low-
+    // Each is kZoneCtrlWidth wide. A click left of the leftmost is the label ("select").
+    // The fields laid out LEFT-TO-RIGHT in slot order 0..6.
+    const ZoneField fields[7] = {
+        ZoneField::kLowDown, ZoneField::kLowUp,  ZoneField::kHighDown,
+        ZoneField::kHighUp,  ZoneField::kRootDown, ZoneField::kRootUp,
+        ZoneField::kDelete,
+    };
+    const int slots = 7;
+    const int ctrlBlockLeft = row.right - slots * kZoneCtrlWidth;
+    if (x < ctrlBlockLeft) return ZoneHit{index, ZoneField::kZoneNone};  // label -> select
+    const int slot = (x - ctrlBlockLeft) / kZoneCtrlWidth;
+    if (slot < 0 || slot >= slots) return ZoneHit{index, ZoneField::kZoneNone};
+    return ZoneHit{index, fields[slot]};
+}
+
+bool addZoneHitTest(const KeymapEditorLayout& layout, int x, int y) {
+    return contains(layout.addZoneButton, x, y);
+}
+
 }  // namespace reasampler::vst

src/vst/editor_geometry.h

@@ -75,4 +75,75 @@ Rect sampleRowRect(const EditorLayout& layout, int index);
 // outside the list (above the first row, past the last, or on the title bar). Pure.
 int sampleRowHitTest(const EditorLayout& layout, int rowCount, int x, int y);
 
+// --- Keymap editor (S5 Tier-1 UI) -------------------------------------------
+//
+// The Tier-1 editor splits the canvas into a LEFT bank-sample list (the same rows as
+// Tier 0, reused for the "sample to add / fallback pick") and a RIGHT zone panel listing
+// the performance map's zones. An "Add Zone" button sits at the top of the zone panel;
+// each zone row carries small nudge/delete controls so the user can set the range and
+// root note without a text field (LICE has no native numeric entry). All rectangle math
+// is here so the shell only draws + routes — the mirror of the sample-list split above.
+
+// Fixed metrics for the zone panel, exposed so the shell and tests agree.
+inline constexpr int kZoneRowHeight = 24;
+inline constexpr int kZonePanelFraction = 2;  // zone panel gets the RIGHT 1/2 of the canvas
+inline constexpr int kZoneCtrlWidth = 20;     // width of one nudge/delete mini-button
+inline constexpr int kAddZoneHeight = 22;     // the "Add Zone" button band height
+
+// The keymap editor's regions, derived from the (w x h) client area. All clamp to the
+// canvas so a degenerate view yields in-bounds rects.
+struct KeymapEditorLayout {
+    EditorLayout base;   // title bar + canvas (the sample list uses base.canvas.left half)
+    Rect sampleList;     // LEFT column: the bank-sample rows (sampleRowRect is relative here)
+    Rect zonePanel;      // RIGHT column: the "Add Zone" button + the zone rows
+    Rect addZoneButton;  // top of the zone panel
+    Rect zoneRowArea;    // below addZoneButton: where zone rows stack
+};
+
+KeymapEditorLayout layoutKeymapEditor(int w, int h);
+
+// The rectangle for bank-sample row `index` inside the LEFT sample list column of a
+// keymap layout. Same fixed height as the Tier-0 list; laid out top-down inside
+// sampleList. Negative index -> empty. Pure.
+Rect keymapSampleRowRect(const KeymapEditorLayout& layout, int index);
+
+// The bank-sample row a click lands on inside the left list, or -1 outside it. Pure.
+int keymapSampleRowHitTest(const KeymapEditorLayout& layout, int rowCount, int x, int y);
+
+// The rectangle for zone row `index` inside the zone panel's zoneRowArea. Negative
+// index -> empty. Pure.
+Rect zoneRowRect(const KeymapEditorLayout& layout, int index);
+
+// A zone row's interactive fields. The row is a horizontal strip: a label on the left,
+// then six fixed-width nudge/delete mini-buttons on the right (low-, low+, high-, high+,
+// root-, root+) followed by a delete button. kZoneNone means the click missed a control
+// (e.g. on the label) — the shell may still treat that as "select this zone".
+enum class ZoneField {
+    kZoneNone,
+    kLowDown,
+    kLowUp,
+    kHighDown,
+    kHighUp,
+    kRootDown,
+    kRootUp,
+    kDelete,
+};
+
+// The result of hit-testing a click against the zone rows: which zone row (or -1) and
+// which field within it. A click on the "Add Zone" button is reported separately by
+// addZoneHitTest — this covers only the zone rows.
+struct ZoneHit {
+    int zoneIndex = -1;
+    ZoneField field = ZoneField::kZoneNone;
+};
+
+// Classify a click at (x, y) against `zoneCount` zone rows. Returns {-1, kZoneNone} for a
+// click outside every zone row. Within a row, the six nudges + delete occupy fixed-width
+// slots on the right edge (right-to-left: delete, root+, root-, high+, high-, low+, low-);
+// a click left of those slots is {index, kZoneNone} (the label area — "select"). Pure.
+ZoneHit zoneHitTest(const KeymapEditorLayout& layout, int zoneCount, int x, int y);
+
+// True if (x, y) lands on the "Add Zone" button. Pure.
+bool addZoneHitTest(const KeymapEditorLayout& layout, int x, int y);
+
 }  // namespace reasampler::vst

src/vst/reasampler_editor.cpp

@@ -38,6 +38,9 @@ const LICE_pixel kColBtnHitBg = LICE_RGBA(58, 96, 84, 255);
 const LICE_pixel kColBtnBorder = LICE_RGBA(120, 200, 160, 255);
 const COLORREF kRgbText = RGB(210, 230, 220);
 
+const LICE_pixel kColZoneSelBg = LICE_RGBA(48, 72, 64, 255);
+const LICE_pixel kColCtrlBg = LICE_RGBA(60, 60, 66, 255);
+
 void drawText(LICE_IBitmap* bmp, const Rect& r, const char* s, COLORREF col) {
     // LICE has no built-in font handle here; use GDI text into the bitmap DC, matching
     // bank_panel's drawCenteredText approach (SetTextColor + DrawText on getDC()).
@@ -47,6 +50,26 @@ void drawText(LICE_IBitmap* bmp, const Rect& r, const char* s, COLORREF col) {
     RECT gr{r.left, r.top, r.right, r.bottom};
     DrawTextA(dc, s, -1, &gr, DT_LEFT | DT_VCENTER | DT_SINGLELINE | DT_NOPREFIX);
 }
+
+void drawTextCentered(LICE_IBitmap* bmp, const Rect& r, const char* s, COLORREF col) {
+    HDC dc = bmp->getDC();
+    SetBkMode(dc, TRANSPARENT);
+    SetTextColor(dc, col);
+    RECT gr{r.left, r.top, r.right, r.bottom};
+    DrawTextA(dc, s, -1, &gr, DT_CENTER | DT_VCENTER | DT_SINGLELINE | DT_NOPREFIX);
+}
+
+// Clamp a MIDI note to [0, 127].
+int clampNote(int n) { return n < 0 ? 0 : (n > 127 ? 127 : n); }
+
+// A short display name for a bank sample id, from the snapshotted list (id if unnamed,
+// "?" if the id no longer resolves — e.g. a stale zone).
+std::string sampleLabel(const std::vector<SampleChoice>& samples, const std::string& id) {
+    for (const SampleChoice& c : samples) {
+        if (c.id == id) return c.displayName.empty() ? c.id : c.displayName;
+    }
+    return "?";  // stale: id not in the live bank
+}
 #endif
 }  // namespace
 
@@ -62,11 +85,26 @@ void ReaSamplerEditor::refreshSampleList() {
     if (!processor_) {
         samples_.clear();
         selectedId_.clear();
+        map_.zones.clear();
+        selectedZone_ = -1;
         return;
     }
     auto banks = processor_->bridge().readReasamplerExtState(reasampler::kProjExtBanksKey);
     samples_ = banks ? listSamples(*banks) : std::vector<SampleChoice>{};
     selectedId_ = processor_->selectedSampleId();
+    map_ = processor_->performanceMap();
+    if (selectedZone_ >= static_cast<int>(map_.zones.size())) selectedZone_ = -1;
+}
+
+void ReaSamplerEditor::commitMapAndReload() {
+    // UI thread only. Publish the edited map to the processor, then rebuild the instrument
+    // off the audio thread (reloadFromBank bakes the zones into the live Keymap).
+    if (!processor_) return;
+    processor_->setPerformanceMap(map_);
+    processor_->reloadFromBank();
+#ifdef _WIN32
+    if (childHwnd_) InvalidateRect(childHwnd_, nullptr, FALSE);
+#endif
 }
 
 ReaSamplerEditor::~ReaSamplerEditor() {
@@ -160,28 +198,33 @@ void ReaSamplerEditor::paint(HDC hdc) {
     LICE_SysBitmap bmp(w, h);
     LICE_Clear(&bmp, kColBackground);
 
-    const EditorLayout layout = layoutEditor(w, h);
+    const KeymapEditorLayout layout = layoutKeymapEditor(w, h);
+    const EditorLayout& base = layout.base;
 
-    // Title band: the plugin name + whether a live bank is linked.
-    LICE_FillRect(&bmp, layout.titleBar.left, layout.titleBar.top,
-                  layout.titleBar.width(), layout.titleBar.height(), kColTitleBg, 1.0f,
-                  0);
+    // Title band: the plugin name + a live-state / mode readout.
+    LICE_FillRect(&bmp, base.titleBar.left, base.titleBar.top, base.titleBar.width(),
+                  base.titleBar.height(), kColTitleBg, 1.0f, 0);
     std::string title = "ReaSampler Instrument";
     if (processor_ && processor_->bridge().isConnected()) {
-        title += samples_.empty() ? "  [bank: empty]" : "  [pick a sample]";
+        if (samples_.empty()) {
+            title += "  [bank: empty]";
+        } else if (map_.zones.empty()) {
+            title += "  [Tier 0: pick a sample - Add Zone for a keymap]";
+        } else {
+            title += "  [keymap: " + std::to_string(map_.zones.size()) + " zone(s)]";
+        }
     } else {
         title += "  [host: no bridge]";
     }
-    Rect titleText{layout.titleBar.left + 8, layout.titleBar.top,
-                   layout.titleBar.right - 8, layout.titleBar.bottom};
+    Rect titleText{base.titleBar.left + 8, base.titleBar.top, base.titleBar.right - 8,
+                   base.titleBar.bottom};
     drawText(&bmp, titleText, title.c_str(), kRgbText);
 
-    // Sample list: one row per bank sample, the selected one highlighted. Clip drawing
-    // to rows that fall within the canvas (sampleRowRect computes all; we skip off-screen
-    // ones so a huge bank doesn't waste paint).
+    // LEFT column: the bank-sample list. The selected id (fallback + "sample to add" for
+    // a new zone) is highlighted. Clip rows past the visible list.
     for (int i = 0; i < static_cast<int>(samples_.size()); ++i) {
-        const Rect row = sampleRowRect(layout, i);
-        if (row.top >= layout.canvas.bottom) break;  // past the visible area
+        const Rect row = keymapSampleRowRect(layout, i);
+        if (row.top >= layout.sampleList.bottom) break;
         const bool sel = !selectedId_.empty() && samples_[i].id == selectedId_;
         LICE_FillRect(&bmp, row.left, row.top, row.width(), row.height(),
                       sel ? kColBtnHitBg : kColBtnBg, 1.0f, 0);
@@ -195,6 +238,44 @@ void ReaSamplerEditor::paint(HDC hdc) {
                  kRgbText);
     }
 
+    // RIGHT column: the zone panel. "Add Zone" button on top, then one row per zone.
+    LICE_FillRect(&bmp, layout.addZoneButton.left, layout.addZoneButton.top,
+                  layout.addZoneButton.width(), layout.addZoneButton.height(), kColBtnBg,
+                  1.0f, 0);
+    LICE_DrawRect(&bmp, layout.addZoneButton.left, layout.addZoneButton.top,
+                  layout.addZoneButton.width() - 1, layout.addZoneButton.height() - 1,
+                  kColBtnBorder, 1.0f, 0);
+    drawTextCentered(&bmp, layout.addZoneButton, "+ Add Zone", kRgbText);
+
+    // The seven per-row controls, laid out left-to-right pinned to the right edge.
+    const char* kCtrlGlyphs[7] = {"-", "+", "-", "+", "-", "+", "x"};
+    for (int i = 0; i < static_cast<int>(map_.zones.size()); ++i) {
+        const Rect row = zoneRowRect(layout, i);
+        if (row.top >= layout.zoneRowArea.bottom) break;  // past the visible panel
+        const bool sel = (i == selectedZone_);
+        LICE_FillRect(&bmp, row.left, row.top, row.width(), row.height(),
+                      sel ? kColZoneSelBg : kColBtnBg, 1.0f, 0);
+
+        const PerformanceZone& z = map_.zones[i];
+        std::string label = sampleLabel(samples_, z.sampleId);
+        label += "  " + std::to_string(z.lowNote) + "-" + std::to_string(z.highNote);
+        label += "  r" + (z.rootOverride ? std::to_string(*z.rootOverride) + "*"
+                                         : std::string("(bank)"));
+        // Label area stops where the control block begins (7 * ctrl width from the right).
+        const int ctrlBlockLeft = row.right - 7 * kZoneCtrlWidth;
+        Rect textR{row.left + 6, row.top, ctrlBlockLeft - 4, row.bottom};
+        drawText(&bmp, textR, label.c_str(), kRgbText);
+
+        // Draw the 7 mini-buttons.
+        for (int s = 0; s < 7; ++s) {
+            const int bx = ctrlBlockLeft + s * kZoneCtrlWidth;
+            Rect cell{bx, row.top + 2, bx + kZoneCtrlWidth - 1, row.bottom - 2};
+            LICE_FillRect(&bmp, cell.left, cell.top, cell.width(), cell.height(),
+                          kColCtrlBg, 1.0f, 0);
+            drawTextCentered(&bmp, cell, kCtrlGlyphs[s], kRgbText);
+        }
+    }
+
     BitBlt(hdc, 0, 0, w, h, bmp.getDC(), 0, 0, SRCCOPY);
 }
 
@@ -202,16 +283,77 @@ void ReaSamplerEditor::onClick(int x, int y) {
     if (!processor_) return;
     RECT cr{};
     GetClientRect(childHwnd_, &cr);
-    const EditorLayout layout = layoutEditor(cr.right - cr.left, cr.bottom - cr.top);
-    const int row = sampleRowHitTest(layout, static_cast<int>(samples_.size()), x, y);
-    if (row < 0) return;
+    const KeymapEditorLayout layout =
+        layoutKeymapEditor(cr.right - cr.left, cr.bottom - cr.top);
 
-    // Select this sample and rebuild the instrument OFF the audio thread (this WM_
-    // handler runs on the UI thread). reloadFromBank reads the id we just set.
-    processor_->setSelectedSampleId(samples_[row].id);
-    processor_->reloadFromBank();
-    selectedId_ = samples_[row].id;
-    InvalidateRect(childHwnd_, nullptr, FALSE);
+    // 1. Left list: pick the Tier-0 fallback / the sample a new zone will use.
+    const int row =
+        keymapSampleRowHitTest(layout, static_cast<int>(samples_.size()), x, y);
+    if (row >= 0) {
+        processor_->setSelectedSampleId(samples_[row].id);
+        selectedId_ = samples_[row].id;
+        // A fallback change only affects playback when the map is empty; reload so the
+        // Tier-0 case updates immediately.
+        processor_->reloadFromBank();
+        InvalidateRect(childHwnd_, nullptr, FALSE);
+        return;
+    }
+
+    // 2. "Add Zone": append a full-keyboard zone for the currently-selected sample (root
+    //    from the bank intrinsic — no override until the user nudges it).
+    if (addZoneHitTest(layout, x, y)) {
+        if (selectedId_.empty()) return;  // nothing selected to add
+        PerformanceZone z;
+        z.sampleId = selectedId_;
+        z.lowNote = 0;
+        z.highNote = 127;
+        map_.zones.push_back(z);
+        selectedZone_ = static_cast<int>(map_.zones.size()) - 1;
+        commitMapAndReload();
+        return;
+    }
+
+    // 3. Zone rows: select a zone, nudge its range/root, or delete it.
+    const ZoneHit hit =
+        zoneHitTest(layout, static_cast<int>(map_.zones.size()), x, y);
+    if (hit.zoneIndex < 0) return;
+    selectedZone_ = hit.zoneIndex;
+
+    if (hit.field == ZoneField::kZoneNone) {
+        InvalidateRect(childHwnd_, nullptr, FALSE);  // select only, no reload
+        return;
+    }
+    if (hit.field == ZoneField::kDelete) {
+        map_.zones.erase(map_.zones.begin() + hit.zoneIndex);
+        selectedZone_ = -1;
+        commitMapAndReload();
+        return;
+    }
+
+    PerformanceZone& z = map_.zones[hit.zoneIndex];
+    switch (hit.field) {
+        case ZoneField::kLowDown:  z.lowNote = clampNote(z.lowNote - 1); break;
+        case ZoneField::kLowUp:    z.lowNote = clampNote(z.lowNote + 1); break;
+        case ZoneField::kHighDown: z.highNote = clampNote(z.highNote - 1); break;
+        case ZoneField::kHighUp:   z.highNote = clampNote(z.highNote + 1); break;
+        case ZoneField::kRootDown: {
+            const int base = z.rootOverride ? *z.rootOverride : 60;
+            z.rootOverride = clampNote(base - 1);  // first nudge establishes the override
+            break;
+        }
+        case ZoneField::kRootUp: {
+            const int base = z.rootOverride ? *z.rootOverride : 60;
+            z.rootOverride = clampNote(base + 1);
+            break;
+        }
+        default: break;  // kZoneNone/kDelete handled above
+    }
+    // Keep low <= high after a range nudge (clamp the moved edge against its partner).
+    if (z.lowNote > z.highNote) {
+        if (hit.field == ZoneField::kLowUp) z.lowNote = z.highNote;
+        else if (hit.field == ZoneField::kHighDown) z.highNote = z.lowNote;
+    }
+    commitMapAndReload();
 }
 
 LRESULT CALLBACK ReaSamplerEditor::wndProc(HWND hwnd, UINT msg, WPARAM wParam,

src/vst/reasampler_editor.h

@@ -54,7 +54,8 @@ private:
 #ifdef _WIN32
     // Draw the current surface into the child window's DC via a LICE bitmap.
     void paint(HDC hdc);
-    // Route a client-space click: select the sample row under (x, y), if any.
+    // Route a client-space click: bank-sample pick (left list), zone edit (right panel),
+    // or the "Add Zone" button.
     void onClick(int x, int y);
 
     static LRESULT CALLBACK wndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
@@ -62,16 +63,28 @@ private:
     HWND childHwnd_ = nullptr;
 #endif
 
-    // Re-read the bank's sample list from the live bridge into `samples_`. Main/UI
-    // thread only (reads ext-state); called on attach and after a selection reload.
+    // Re-read the bank's sample list from the live bridge into `samples_`, and snapshot the
+    // instrument's performance map. Main/UI thread only (reads ext-state); called on attach
+    // and after any edit that reloads the instrument.
     void refreshSampleList();
 
+    // Push the edited performance map to the processor and rebuild the instrument OFF the
+    // audio thread. UI thread only. Centralizes the "commit an edit" path so every zone
+    // mutation reloads identically.
+    void commitMapAndReload();
+
     ReaSamplerProcessor* processor_ = nullptr;
     // The bank's samples, snapshotted for the current paint. Refreshed off the audio
     // thread; the paint just draws it.
     std::vector<SampleChoice> samples_;
-    // The currently-selected sample id, mirrored for the paint's highlight.
+    // The currently-selected sample id (Tier-0 fallback + the "sample to add" for a new
+    // zone), mirrored for the paint's highlight.
     std::string selectedId_;
+    // The instrument's performance map, snapshotted for edit + paint. Edits mutate this
+    // copy then commit it to the processor via commitMapAndReload.
+    PerformanceMap map_;
+    // The zone row currently highlighted (for the paint); -1 = none.
+    int selectedZone_ = -1;
 };
 
 }  // namespace reasampler::vst

src/vst/reasampler_processor.cpp

@@ -5,6 +5,8 @@
 #include <algorithm>
 #include <cstdint>
 #include <fstream>
+#include <optional>
+#include <utility>
 #include <vector>
 
 #include "pluginterfaces/base/ibstream.h"
@@ -15,7 +17,7 @@
 #include "capture_paths.h"   // resolveBankFile (shared M4 path resolution)
 #include "ext_keys.h"        // kProjExtBanksKey (shared wire contract)
 #include "reasampler_editor.h"
-#include "sample_map.h"       // selectSample, downmixToMono, buildTier0Keymap, state (de)ser
+#include "sample_map.h"       // selectSample, resolvePerformance, buildZonedKeymap, state (de)ser
 #include "wav_trim.h"         // parseWavLayout, extractFloatFrames (shared WAV parse)
 
 using namespace Steinberg;
@@ -59,6 +61,28 @@ std::vector<std::uint8_t> readFileBytes(const std::string& path) {
     return bytes;
 }
 
+// Resolve a project-relative WAV path (the M4 way persist does), read + decode it (file
+// I/O — off-thread only), and downmix to the core's mono contract. Returns nullopt when
+// the path fails to resolve, the file is unreadable, the WAV is malformed, or the decode
+// yields no frames — the caller drops the zone (Tier 1) or plays silence (Tier 0). Shared
+// by the zoned build and the Tier-0 fallback so both decode identically.
+std::optional<DecodedZonePcm> decodeRelative(const std::string& projectDir,
+                                             const std::string& relativePath) {
+    const std::string abs = resolveBankFile(projectDir, relativePath);
+    if (abs.empty()) return std::nullopt;
+    const std::vector<std::uint8_t> bytes = readFileBytes(abs);
+    const WavLayout layout = parseWavLayout(bytes);
+    if (!layout.valid) return std::nullopt;
+    std::vector<AudioSample> interleaved =
+        extractFloatFrames(bytes, layout, 0, layout.frameCount());
+    std::vector<AudioSample> mono = downmixToMono(interleaved, layout.channelCount);
+    if (mono.empty()) return std::nullopt;
+    DecodedZonePcm out;
+    out.monoFrames = std::move(mono);
+    out.sampleRate = static_cast<int>(layout.sampleRate);
+    return out;
+}
+
 }  // namespace
 
 FUnknown* ReaSamplerProcessor::createInstance(void* /*context*/) {
@@ -115,23 +139,33 @@ tresult PLUGIN_API ReaSamplerProcessor::setupProcessing(ProcessSetup& setup) {
 
 tresult PLUGIN_API ReaSamplerProcessor::setState(IBStream* state) {
     if (!state) return kResultFalse;
-    // Read the whole component-state blob (the selected sample id, versioned). The blob
-    // is small; read in one shot into a growable buffer.
+    // Read the whole component-state blob (the performance map, versioned). The blob is
+    // small; read in one shot into a growable buffer.
     std::vector<std::uint8_t> bytes;
     std::uint8_t chunk[256];
     int32 got = 0;
     while (state->read(chunk, sizeof(chunk), &got) == kResultOk && got > 0) {
         bytes.insert(bytes.end(), chunk, chunk + got);
     }
-    setSelectedSampleId(deserializeSelection(bytes));
-    // Rebuild from the restored selection (off-thread — setState is a load-time call).
+    // Component state IS the performance map (Tier 1, D-B). deserializePerformance lifts a
+    // v1 (S4 single-selection) blob to a one-zone map, so already-saved Tier-0 instances
+    // restore cleanly. When the restored map is empty, the instrument falls back to the
+    // Tier-0 first-sample in reloadFromBank; if the v1 lift produced a single zone we also
+    // seed the fallback selection from it so the editor reflects the restored pick.
+    const PerformanceMap map = deserializePerformance(bytes);
+    setPerformanceMap(map);
+    if (map.zones.size() == 1) setSelectedSampleId(map.zones.front().sampleId);
+    // Rebuild from the restored state (off-thread — setState is a load-time call).
     reloadFromBank();
     return kResultOk;
 }
 
 tresult PLUGIN_API ReaSamplerProcessor::getState(IBStream* state) {
     if (!state) return kResultFalse;
-    const std::vector<std::uint8_t> bytes = serializeSelection(selectedSampleId());
+    // Persist the performance map (the instrument's own Tier-1 state, D-B — NEVER written
+    // to the "reasampler" bank ext-state). An empty map serializes to just the version +
+    // zero-count header (restores as empty -> Tier-0 fallback).
+    const std::vector<std::uint8_t> bytes = serializePerformance(performanceMap());
     if (!bytes.empty()) {
         const tresult wr = state->write(const_cast<std::uint8_t*>(bytes.data()),
                                         static_cast<int32>(bytes.size()), nullptr);
@@ -150,6 +184,16 @@ void ReaSamplerProcessor::setSelectedSampleId(const std::string& id) {
     selectedSampleId_ = id;
 }
 
+PerformanceMap ReaSamplerProcessor::performanceMap() {
+    std::lock_guard<std::mutex> lock(performanceMutex_);
+    return performanceMap_;
+}
+
+void ReaSamplerProcessor::setPerformanceMap(const PerformanceMap& map) {
+    std::lock_guard<std::mutex> lock(performanceMutex_);
+    performanceMap_ = map;
+}
+
 std::string ReaSamplerProcessor::reloadFromBank() {
     // OFF THE AUDIO THREAD. Serialize concurrent reloads (editor click + setState) so
     // the retired-slot free is single-writer. This mutex is NEVER taken on the audio
@@ -170,36 +214,58 @@ std::string ReaSamplerProcessor::reloadFromBank() {
     std::unique_ptr<LoadedInstrument> built;
 
     if (banksJson) {
-        // 2. Pick the sample (shared bank_book JSON parse — NOT a second parser).
-        std::optional<SelectedSample> sel =
-            selectSample(*banksJson, selectedSampleId());
-        if (sel) {
-            // 3. Resolve the project-relative WAV path the M4 way persist does, read +
-            //    decode it (file I/O off-thread), downmix to the core's mono contract.
-            const std::string abs = resolveBankFile(projectDir, sel->relativePath);
-            if (!abs.empty()) {
-                const std::vector<std::uint8_t> bytes = readFileBytes(abs);
-                const WavLayout layout = parseWavLayout(bytes);
-                if (layout.valid) {
-                    const std::size_t frames = layout.frameCount();
-                    std::vector<AudioSample> interleaved =
-                        extractFloatFrames(bytes, layout, 0, frames);
-                    std::vector<AudioSample> mono =
-                        downmixToMono(interleaved, layout.channelCount);
-                    if (!mono.empty()) {
-                        Keymap km = buildTier0Keymap(
-                            std::move(mono),
-                            static_cast<int>(layout.sampleRate), sel->rootNote,
-                            sel->loop);
-                        built = std::make_unique<LoadedInstrument>(
-                            std::move(km), kMaxVoices, tier0Adsr(sampleRate_), gen);
-                        // Record which id actually resolved so a first-sample fallback
-                        // (empty stored id) becomes the concrete selection.
-                        resolvedId = selectedSampleId();
-                    }
+        // 2. Tier 1 first: if the instrument's performance map is non-empty, resolve its
+        //    zones against the live bank (STALE ids drop cleanly), decode each zone's WAV
+        //    off-thread, and build the ZONED keymap. Each surviving zone plays its bank
+        //    sample repitched from its effective root note (override > bank intrinsic > C4).
+        //    A zone whose WAV fails to decode is dropped (not the whole map).
+        const PerformanceMap map = performanceMap();
+        Keymap km;
+        bool haveKeymap = false;
+
+        if (!map.empty()) {
+            const ResolvedPerformance resolved = resolvePerformance(*banksJson, map);
+            if (!resolved.zones.empty()) {
+                std::vector<DecodedZonePcm> decoded;
+                std::vector<ResolvedZone> kept;
+                decoded.reserve(resolved.zones.size());
+                kept.reserve(resolved.zones.size());
+                for (const ResolvedZone& rz : resolved.zones) {
+                    std::optional<DecodedZonePcm> pcm =
+                        decodeRelative(projectDir, rz.relativePath);
+                    if (!pcm) continue;  // unreadable WAV -> drop this zone
+                    kept.push_back(rz);
+                    decoded.push_back(std::move(*pcm));
+                }
+                km = buildZonedKeymap(kept, decoded);
+                haveKeymap = !km.zones.empty();
+            }
+        }
+
+        // 3. Tier-0 fallback: an empty (or fully-unresolvable) performance map plays the
+        //    selected fallback sample chromatically across the whole keyboard — preserving
+        //    the S4 "the bank plays" behavior for an un-authored instrument.
+        if (!haveKeymap) {
+            std::optional<SelectedSample> sel =
+                selectSample(*banksJson, selectedSampleId());
+            if (sel) {
+                std::optional<DecodedZonePcm> pcm =
+                    decodeRelative(projectDir, sel->relativePath);
+                if (pcm) {
+                    km = buildTier0Keymap(std::move(pcm->monoFrames), pcm->sampleRate,
+                                          sel->rootNote, sel->loop);
+                    haveKeymap = true;
+                    // Record which id actually resolved so a first-sample fallback
+                    // (empty stored id) becomes the concrete selection.
+                    resolvedId = selectedSampleId();
                 }
             }
         }
+
+        if (haveKeymap) {
+            built = std::make_unique<LoadedInstrument>(
+                std::move(km), kMaxVoices, tier0Adsr(sampleRate_), gen);
+        }
     }
 
     // 4. Publish. Atomically install the new instrument; the DISPLACED one goes to the

src/vst/reasampler_processor.h

@@ -28,6 +28,7 @@
 #include "public.sdk/source/vst/vstsinglecomponenteffect.h"
 
 #include "reaper_bridge.h"
+#include "sample_map.h"     // PerformanceMap (the instrument's owned zoned keymap)
 #include "sampler_core.h"
 
 namespace reasampler::vst {
@@ -97,10 +98,18 @@ public:
     // editor borrows it (outlives the editor).
     ReaperBridge& bridge() { return bridge_; }
     // The current selection id (main/UI thread reads for the editor). Guarded by
-    // selectionMutex_ — never touched on the audio thread.
+    // selectionMutex_ — never touched on the audio thread. In Tier 1 the selection is the
+    // Tier-0 FALLBACK sample (played chromatically when the performance map is empty); the
+    // zoned map, when non-empty, supersedes it.
     std::string selectedSampleId();
     void setSelectedSampleId(const std::string& id);
 
+    // The performance map (Tier 1: the zoned keymap the instrument owns; D-B). Read/written
+    // by the editor on the UI thread; snapshotted under performanceMutex_. NEVER read on the
+    // audio thread — reloadFromBank bakes it into the LoadedInstrument's Keymap off-thread.
+    PerformanceMap performanceMap();
+    void setPerformanceMap(const PerformanceMap& map);
+
 private:
     ReaperBridge bridge_;
 
@@ -139,11 +148,17 @@ private:
     std::vector<GraveyardEntry> graveyard_;  // drained on reclaim + setActive(false) + terminate
     std::mutex reloadMutex_;  // serializes off-thread reloads + graveyard access
 
-    // The selected sample id (instance state). Off-thread only; a small mutex guards the
-    // string against a getState/editor race. NOT read on the audio thread.
+    // The selected sample id (Tier-0 fallback sample). Off-thread only; a small mutex
+    // guards the string against a getState/editor race. NOT read on the audio thread.
     std::mutex selectionMutex_;
     std::string selectedSampleId_;
 
+    // The performance map (Tier 1: the instrument's owned zoned keymap). Off-thread only;
+    // guarded against a getState/editor race. NOT read on the audio thread — reloadFromBank
+    // bakes it into the LoadedInstrument's Keymap under the reload lock.
+    std::mutex performanceMutex_;
+    PerformanceMap performanceMap_;
+
     // Latched from setupProcessing so setActive/reload can size against it. Read
     // off-thread only.
     double sampleRate_ = 44100.0;

src/vst/sample_map.cpp

@@ -3,7 +3,9 @@
 
 #include "sample_map.h"
 
-#include <cstring>  // std::memcpy
+#include <algorithm>  // std::min
+#include <cstring>    // std::memcpy
+#include <utility>    // std::move
 
 namespace reasampler {
 
@@ -103,6 +105,168 @@ Keymap buildTier0Keymap(std::vector<AudioSample> monoFrames, int sampleRate,
     return Keymap::singleSampleChromatic(std::move(data));
 }
 
+// --- Performance map ---------------------------------------------------------
+
+ResolvedPerformance resolvePerformance(const std::string& banksJson,
+                                       const PerformanceMap& map) {
+    ResolvedPerformance out;
+    if (map.zones.empty()) return out;             // empty map -> empty (shell -> Tier 0)
+    if (banksJson.empty()) return out;             // no bank -> nothing resolves
+    std::optional<BankBook> book = BankBook::deserialize(banksJson);
+    if (!book) return out;                         // malformed -> nothing (never throw)
+
+    for (const PerformanceZone& z : map.zones) {
+        // Look the id up across every bank (pool + named) — a sample lives in exactly
+        // one bank, so first hit wins.
+        const Sample* found = nullptr;
+        for (const Bank& b : book->banks()) {
+            if (const Sample* s = b.index.query(z.sampleId)) {
+                found = s;
+                break;
+            }
+        }
+        if (!found) {
+            // STALE-ID POLICY: drop the zone cleanly, report the id (editor can prune).
+            out.droppedSampleIds.push_back(z.sampleId);
+            continue;
+        }
+        ResolvedZone rz;
+        rz.relativePath = found->relativePath;
+        rz.lowNote = z.lowNote;
+        rz.highNote = z.highNote;
+        // Effective root: override beats bank intrinsic beats middle-C default.
+        rz.rootNote = z.rootOverride ? *z.rootOverride
+                                     : (found->rootNote ? *found->rootNote : 60);
+        rz.loop = loopFromSample(*found);
+        out.zones.push_back(std::move(rz));
+    }
+    return out;
+}
+
+Keymap buildZonedKeymap(const std::vector<ResolvedZone>& zones,
+                        const std::vector<DecodedZonePcm>& decoded) {
+    Keymap km;
+    const std::size_t n = std::min(zones.size(), decoded.size());
+    for (std::size_t i = 0; i < n; ++i) {
+        // An unreadable/empty WAV drops just this zone (not the whole map).
+        if (decoded[i].monoFrames.empty()) continue;
+        SampleData data;
+        data.frames = decoded[i].monoFrames;
+        data.sampleRate = decoded[i].sampleRate > 0 ? decoded[i].sampleRate : 44100;
+        data.rootNote = zones[i].rootNote;
+        data.loop = zones[i].loop;
+        const std::size_t sampleIndex = km.samples.size();
+        km.samples.push_back(std::move(data));
+        KeyZone zone;
+        zone.lowNote = zones[i].lowNote;
+        zone.highNote = zones[i].highNote;
+        zone.rootNote = zones[i].rootNote;
+        zone.sampleIndex = sampleIndex;
+        km.zones.push_back(zone);
+    }
+    return km;  // empty zones in -> empty Keymap (silence)
+}
+
+// --- Performance-map instance state (setState/getState) -----------------------
+
+namespace {
+
+void putU32le(std::vector<std::uint8_t>& out, std::uint32_t v) {
+    out.push_back(static_cast<std::uint8_t>(v & 0xFF));
+    out.push_back(static_cast<std::uint8_t>((v >> 8) & 0xFF));
+    out.push_back(static_cast<std::uint8_t>((v >> 16) & 0xFF));
+    out.push_back(static_cast<std::uint8_t>((v >> 24) & 0xFF));
+}
+
+// A bounded little-endian reader over a byte blob. Every read is length-checked; once a
+// read runs past the end the reader latches `ok=false` and yields zeros, so a truncated
+// blob degrades to a partial/empty parse rather than reading out of bounds.
+struct ByteReader {
+    const std::vector<std::uint8_t>& bytes;
+    std::size_t pos = 0;
+    bool ok = true;
+
+    explicit ByteReader(const std::vector<std::uint8_t>& b) : bytes(b) {}
+
+    std::uint32_t u32() {
+        if (!ok || pos + 4 > bytes.size()) { ok = false; return 0; }
+        const std::uint32_t v = static_cast<std::uint32_t>(bytes[pos]) |
+                                (static_cast<std::uint32_t>(bytes[pos + 1]) << 8) |
+                                (static_cast<std::uint32_t>(bytes[pos + 2]) << 16) |
+                                (static_cast<std::uint32_t>(bytes[pos + 3]) << 24);
+        pos += 4;
+        return v;
+    }
+    std::uint8_t u8() {
+        if (!ok || pos + 1 > bytes.size()) { ok = false; return 0; }
+        return bytes[pos++];
+    }
+    std::string str(std::uint32_t len) {
+        if (!ok || pos + len > bytes.size()) { ok = false; return {}; }
+        std::string s(reinterpret_cast<const char*>(bytes.data() + pos), len);
+        pos += len;
+        return s;
+    }
+    // Signed ints go on the wire as u32 two's-complement (fixed 32-bit width).
+    int i32() { return static_cast<int>(static_cast<std::int32_t>(u32())); }
+};
+
+}  // namespace
+
+std::vector<std::uint8_t> serializePerformance(const PerformanceMap& map) {
+    std::vector<std::uint8_t> out;
+    putU32le(out, kPerformanceStateVersion);
+    putU32le(out, static_cast<std::uint32_t>(map.zones.size()));
+    for (const PerformanceZone& z : map.zones) {
+        putU32le(out, static_cast<std::uint32_t>(z.sampleId.size()));
+        out.insert(out.end(), z.sampleId.begin(), z.sampleId.end());
+        putU32le(out, static_cast<std::uint32_t>(static_cast<std::int32_t>(z.lowNote)));
+        putU32le(out, static_cast<std::uint32_t>(static_cast<std::int32_t>(z.highNote)));
+        out.push_back(z.rootOverride ? 1 : 0);
+        if (z.rootOverride) {
+            putU32le(out,
+                     static_cast<std::uint32_t>(static_cast<std::int32_t>(*z.rootOverride)));
+        }
+    }
+    return out;
+}
+
+PerformanceMap deserializePerformance(const std::vector<std::uint8_t>& bytes) {
+    PerformanceMap map;
+    ByteReader r(bytes);
+    const std::uint32_t version = r.u32();
+    if (!r.ok) return map;  // no version tag -> empty
+
+    // BACK-COMPAT: a v1 blob is the S4 single-selection format (version 1 + id bytes,
+    // no length prefix). Lift it to one full-keyboard zone playing that id.
+    if (version == kSelectionStateVersion) {
+        const std::string id = deserializeSelection(bytes);
+        if (!id.empty()) {
+            PerformanceZone z;
+            z.sampleId = id;
+            z.lowNote = 0;
+            z.highNote = 127;
+            map.zones.push_back(std::move(z));
+        }
+        return map;
+    }
+    if (version != kPerformanceStateVersion) return map;  // unknown -> empty
+
+    const std::uint32_t count = r.u32();
+    for (std::uint32_t i = 0; i < count && r.ok; ++i) {
+        PerformanceZone z;
+        const std::uint32_t idLen = r.u32();
+        z.sampleId = r.str(idLen);
+        z.lowNote = r.i32();
+        z.highNote = r.i32();
+        const std::uint8_t hasOverride = r.u8();
+        if (hasOverride) z.rootOverride = r.i32();
+        if (!r.ok) break;  // truncated mid-zone -> keep what parsed cleanly, drop the rest
+        map.zones.push_back(std::move(z));
+    }
+    return map;
+}
+
 std::vector<std::uint8_t> serializeSelection(const std::string& sampleId) {
     std::vector<std::uint8_t> out;
     out.resize(4 + sampleId.size());

src/vst/sample_map.h

@@ -85,6 +85,107 @@ std::vector<AudioSample> downmixToMono(const std::vector<AudioSample>& interleav
 Keymap buildTier0Keymap(std::vector<AudioSample> monoFrames, int sampleRate,
                         int rootNote, const SampleLoop& loop);
 
+// --- Performance map (Tier 1, D-B: the instrument's OWN state) ---------------
+//
+// The performance map is the keymap the user authors IN the instrument: several bank
+// samples zoned across the keyboard, each with a key range and a root note. It is a
+// PERFORMANCE CHOICE (D-B), so it lives in the instrument (VST3 component state), never
+// written back to the bank. Root note per zone is SEEDED from the S2 bank intrinsic but
+// OVERRIDABLE here — the override lives on the zone, never on `Sample`.
+//
+// Pure value type: it names bank samples by id (the stable seam key) and holds no PCM.
+// The shell resolves each id's WAV over the file seam and decodes it; the pure zone-build
+// stitches the decoded frames + this map into a sampler_core Keymap.
+
+// One authored zone: a bank sample mapped to an inclusive [lowNote, highNote] key range,
+// with an optional root-note override. rootOverride absent -> repitch from the bank
+// sample's own S2 rootNote intrinsic (or middle C when the bank left it empty).
+struct PerformanceZone {
+    std::string sampleId;             // bank sample id this zone plays
+    int lowNote = 0;                  // inclusive
+    int highNote = 127;               // inclusive
+    std::optional<int> rootOverride;  // instrument-owned override; absent -> bank intrinsic
+};
+
+// The instrument's performance map: an ordered list of zones. Order is authoritative for
+// overlap resolution (OVERLAP POLICY: first zone in order wins, mirroring the S3 core's
+// first-match Keymap::resolve — overlaps are neither rejected nor clamped, the earlier
+// zone simply takes the contested keys; documented, deterministic).
+struct PerformanceMap {
+    std::vector<PerformanceZone> zones;
+
+    bool empty() const { return zones.empty(); }
+};
+
+// One resolved zone ready for the shell to decode + the pure build to stitch: the bank
+// sample's project-relative WAV path (file seam), the EFFECTIVE root note (override beats
+// bank intrinsic beats middle-C default), the loop intrinsic, and the key range. Distinct
+// from PerformanceZone (which names an id) — this is the id resolved against the live bank.
+struct ResolvedZone {
+    std::string relativePath;   // project-relative; the shell resolves + decodes it
+    int lowNote = 0;
+    int highNote = 127;
+    int rootNote = 60;          // effective: override, else bank intrinsic, else 60
+    SampleLoop loop;            // bank intrinsic
+};
+
+// The result of resolving a performance map against the live bank blob. `zones` are the
+// zones whose sampleId still resolves to a bank sample, IN MAP ORDER (so overlap-order is
+// preserved). `droppedSampleIds` are the ids that no longer resolve (STALE-ID POLICY: a
+// zone naming a deleted/moved-out sample is DROPPED cleanly — not an error, not silence
+// for the whole map — and its id is reported here so the editor can flag/prune it).
+struct ResolvedPerformance {
+    std::vector<ResolvedZone> zones;
+    std::vector<std::string> droppedSampleIds;
+};
+
+// Resolve a performance map against the live "banks" ext-state blob. Pure: shared
+// bank_book parse, no host, no PCM. Each zone's sampleId is looked up across every bank
+// (pool + named); a hit yields a ResolvedZone with the effective root note (rootOverride,
+// else the sample's S2 rootNote, else 60) and the sample's loop intrinsic; a miss appends
+// the id to droppedSampleIds. Empty/malformed blob or empty map -> empty result (the shell
+// then falls back to Tier-0 — see reloadFromBank).
+ResolvedPerformance resolvePerformance(const std::string& banksJson,
+                                       const PerformanceMap& map);
+
+// Build a zoned Keymap from resolved zones + their decoded mono PCM. `decoded[i]` is the
+// downmixed frames + sample rate for `zones[i]` (same length + order as `zones`). One
+// SampleData per zone (Tier 1: one sample per key-region; a sample used by two zones is
+// decoded twice — acceptable at this tier, the shell may dedup by path later). Zone order
+// is preserved so first-match overlap resolution matches the map's authored order. A zone
+// whose decoded frames are empty is SKIPPED (an unreadable WAV drops the zone, not the
+// map). Empty zones in -> empty Keymap (silence).
+struct DecodedZonePcm {
+    std::vector<AudioSample> monoFrames;
+    int sampleRate = 44100;
+};
+Keymap buildZonedKeymap(const std::vector<ResolvedZone>& zones,
+                        const std::vector<DecodedZonePcm>& decoded);
+
+// --- Performance-map instance state (VST3 setState/getState) -----------------
+//
+// The performance map is the instrument's OWN state (D-B), serialized to the VST3
+// component-state IBStream — NOT written to the "reasampler" bank ext-state (the
+// instrument is a read-only bank consumer; S4 precedent). Versioned binary, tolerant of
+// truncation/wrong-version by design (bounded reads, never throws across the host).
+//
+// Format (v2): 4-byte LE version tag (== 2), then a 4-byte LE zone count, then per zone:
+//   4-byte LE id length, id bytes, 4-byte LE lowNote, 4-byte LE highNote,
+//   1 byte hasOverride (0/1), 4-byte LE rootOverride (present only when hasOverride==1).
+// BACK-COMPAT: a v1 blob (the S4 single-selection format: version tag 1 + id bytes) is
+// lifted to a single full-keyboard zone playing that id (no override) — so an instance
+// saved under Tier 0 restores as a one-zone Tier-1 map. A truncated/unknown/empty blob
+// deserializes to an EMPTY map (the instrument falls back to Tier-0 first-sample).
+
+inline constexpr std::uint32_t kPerformanceStateVersion = 2;
+
+// The performance map serialized to bytes for IBStream (getState).
+std::vector<std::uint8_t> serializePerformance(const PerformanceMap& map);
+
+// The performance map parsed back from IBStream bytes (setState). A v2 blob parses
+// directly; a v1 blob lifts to a single full-keyboard zone; anything else -> empty map.
+PerformanceMap deserializePerformance(const std::vector<std::uint8_t>& bytes);
+
 // --- Instance state (VST3 setState/getState) --------------------------------
 //
 // The instrument's OWN state is which bank sample it plays (D-B: the selection is a