fix(S12 review): per-zone A/D/S/R reaches voice; zones payload v4 + v3 back-compat

Voice::start reads full zone ADSR instead of folding only holdFrames into instrument-wide gateAdsr. Wire format bumped to v4 (four new fields); v3 blobs lift A/D/S/R to kTier0Nominal* constants. Single-capture editor controls now reachable. Minor comment and geometry fixes.

tests/test_sampler_core.cpp

@@ -383,10 +383,14 @@ static void testOutOfZoneNoteConsumesNoVoice() {
 // ---------------------------------------------------------------------------
 
 static void testStealsReleasingVoiceFirst() {
-    Keymap km = Keymap::singleSampleChromatic(dcSample(100000, 60));
-    AdsrParams a = flatAdsr();
-    a.releaseFrames = 100000;  // long release so a released voice stays "active".
-    VoiceEngine eng(2, km, a);
+    // Long per-zone release so the voice stays active through the release tail.
+    // Per the S12 fix, Voice::start uses sample.play.adsr — not the engine's gateAdsr —
+    // so the long release must live on the SampleData, not on the VoiceEngine constructor arg.
+    SampleData s = dcSample(100000, 60);
+    s.play.adsr = flatAdsr();
+    s.play.adsr.releaseFrames = 100000;  // long release so a released voice stays "active"
+    Keymap km = Keymap::singleSampleChromatic(std::move(s));
+    VoiceEngine eng(2, km, flatAdsr());
 
     std::size_t vA = eng.noteOn(60, 100);  // startOrder 1
     std::size_t vB = eng.noteOn(62, 100);  // startOrder 2
@@ -406,10 +410,12 @@ static void testStealsReleasingVoiceFirst() {
 }
 
 static void testStealsOldestWhenNoneReleasing() {
-    Keymap km = Keymap::singleSampleChromatic(dcSample(100000, 60));
-    AdsrParams a = flatAdsr();
-    a.releaseFrames = 100000;
-    VoiceEngine eng(2, km, a);
+    // Long per-zone release — placed on SampleData.play.adsr per the S12 fix.
+    SampleData s = dcSample(100000, 60);
+    s.play.adsr = flatAdsr();
+    s.play.adsr.releaseFrames = 100000;
+    Keymap km = Keymap::singleSampleChromatic(std::move(s));
+    VoiceEngine eng(2, km, flatAdsr());
 
     std::size_t vA = eng.noteOn(60, 100);  // startOrder 1 (oldest)
     std::size_t vB = eng.noteOn(62, 100);  // startOrder 2
@@ -1177,6 +1183,57 @@ static void testPreserveVoiceCap() {
     CHECK(eng.activeVoiceCount() == 2);
 }
 
+// --- S12 review fix: per-zone A/D/S/R actually reaches the voice envelope. ---
+//
+// Before the fix, Voice::start used the instrument-wide gateAdsr for A/D/S/R and only
+// folded the per-zone holdFrames. These two tests assert the corrected path.
+
+// The zone's attackFrames drives the envelope ramp — NOT the VoiceEngine's gateAdsr.
+// Strategy: give the VoiceEngine a FLAT gateAdsr (instant attack) but put an explicit
+// 10-frame attack on the SampleData.play.adsr. If Voice::start reads the zone ADSR, the
+// DC-1 output will be 0 at frame 0 and 1.0 after the 10-frame ramp. If it instead used
+// gateAdsr (flat = instant), frame 0 would already be 1.0. This is the load-bearing proof.
+static void testPerZoneAdsrReachesVoiceEnvelope() {
+    SampleData s = dcSample(500, 60);
+    // Per-zone attack = 10 frames, zero decay, sustain 1.0, zero release.
+    s.play.adsr.attackFrames  = 10;
+    s.play.adsr.holdFrames    = 0;
+    s.play.adsr.decayFrames   = 0;
+    s.play.adsr.sustainLevel  = 1.0;
+    s.play.adsr.releaseFrames = 0;
+    s.play.pitchEngine = PitchEngine::Varispeed;  // isolate from pitch engine machinery
+    Keymap km = Keymap::singleSampleChromatic(std::move(s));
+    VoiceEngine eng(1, km, flatAdsr());  // instrument-wide gateAdsr = flat (instant attack)
+    eng.noteOn(60, 127);  // unity pitch, full velocity -> gain 1.0
+    std::vector<AudioSample> out;
+    eng.render(out, 20);
+    // Frame 0: attack start, envelope near 0. If gateAdsr (flat) were used, this would be 1.0.
+    CHECK(approx(out[0], 0.0, 1e-9));    // env still at bottom of ramp
+    // Frame 9: still ramping (last attack frame, linear ramp reaches 0.9).
+    CHECK(out[9] < 1.0 - 1e-9);
+    // Frame 10+: attack complete, sustain at 1.0.
+    CHECK(approx(out[10], 1.0, 1e-9));
+    CHECK(approx(out[19], 1.0, 1e-9));
+}
+
+// Default-valued zone (AdsrParams all zeros) is behavior-identical to the pre-fix flat path.
+// A zero-init AdsrParams (attackFrames=0, decayFrames=0, sustainLevel=1.0, releaseFrames=0) must
+// yield an instant-attack/instant-sustain voice — frame 0 immediately at 1.0. This preserves the
+// back-compat invariant: an old zone with no A/D/S/R storage sounds the same as before.
+static void testZeroAdsrIsInstantSustain() {
+    SampleData s = dcSample(20, 60);
+    // Default AdsrParams{}: all zeros, sustainLevel = 1.0 (struct default). No attack ramp.
+    s.play.adsr = AdsrParams{};
+    s.play.pitchEngine = PitchEngine::Varispeed;
+    Keymap km = Keymap::singleSampleChromatic(std::move(s));
+    VoiceEngine eng(1, km, flatAdsr());
+    eng.noteOn(60, 127);
+    std::vector<AudioSample> out;
+    eng.render(out, 5);
+    // All frames must be 1.0: zero attack + sustain 1.0 = instantly at full level.
+    for (std::size_t i = 0; i < out.size(); ++i) CHECK(approx(out[i], 1.0, 1e-9));
+}
+
 int main() {
     testChromaticSingleRoot();
     testZonedRangesBoundaries();
@@ -1228,6 +1285,10 @@ int main() {
     testPreserveGateStereoLoopComposes();
     testPreserveVoiceCap();
 
+    // S12 review fix — per-zone A/D/S/R reaches the voice envelope.
+    testPerZoneAdsrReachesVoiceEnvelope();
+    testZeroAdsrIsInstantSustain();
+
     if (g_fail == 0) {
         std::printf("all sampler_core tests passed\n");
         return 0;