Bake reset: assert the limiter and bake Hold land neutral, prove the loop returns parked, and baseline the render's identity path

resetAfterBake is unchanged — every value already resets by construction. The render prints master gain but not the limiter, so §3.4's rationale is wrong; the invariant is corrected.

src/core/instrument/bake/CLAUDE.md

@@ -21,8 +21,9 @@ decision about what the render made obsolete.
   loop runs to `BakePlan::renderFrames()` and stops. That is why a Gate bake with a sustain
   loop active terminates: the gate is released at `noteOffFrame` so the tail is real, but
   even a pathological envelope cannot run past the window.
-- **The whole signal chain is printed, master gain included** — the gain multiply in
+- **The voice chain and master gain are printed; the limiter is not.** The gain multiply in
-  `bake_render.cpp` carries the argument for why.
+  `bake_render.cpp` carries the argument for the gain, and `bake_reset.h` records where the
+  printed master stage stops.
 - **A degenerate or unholdable window is refused, not rendered.** `planBake` refuses a
   collapsed window, a non-positive rate, a window that rounds to no frames, and one past
   `kMaxBakeFrames` — an unbounded window is a `bad_alloc` inside a UI tick, and the

src/core/instrument/bake/CMakeLists.txt

@@ -17,4 +17,6 @@ reasampler_test(bake_window LINK bake_plan bake_render)
 
 # sample_map carries InstrumentParams, which is the whole of what a reset rewrites.
 reasampler_pure_library(bake_reset SOURCES bake_reset.cpp LINK PUBLIC sample_map)
-reasampler_test(bake_reset LINK bake_reset)
+# loop_marks is a TEST-only edge: it defines what a neutral loop looks like on the band, so
+# the reset's loop assertions read it rather than restating it.
+reasampler_test(bake_reset LINK bake_reset loop_marks)

src/core/instrument/bake/bake_reset.h

@@ -13,6 +13,10 @@ namespace reasampler::instrument::bake {
 // The two surfaces a bake resets. Master gain lives on the processor rather than in the
 // parameter set; it is answered here because renderBake prints it into the file (see
 // bake_render.cpp's gain multiply) rather than left to the shell.
+//
+// Gain is the ONLY master-stage control the render prints — the limiter runs in the
+// processor's block, off the bake path — so "the bake prints the gain" does not generalize
+// to the master stage as a whole, and cannot be used to classify anything else on it.
 struct BakeReset {
     map::InstrumentParams params;
     double masterGainLinear = 1.0;  // unity — renderBake printed the dialed gain

tests/test_bake_render.cpp

@@ -231,6 +231,42 @@ int main() {
         CHECK(identical);
     }
 
+    // --- Regression baseline: the neutral render is the source, sample for sample --------
+    // DERIVED rather than recorded, so it survives a compiler change: a Trigger voice at its
+    // own root under Varispeed, with the default flat amp and velocity shapes and no filter,
+    // reads at ratio exactly 1 — so every printed frame must BE its source frame. An added
+    // stage, a moved default, or a lost early-out anywhere in the chain moves a sample here.
+    {
+        SampleData s;
+        s.frames.resize(4000);
+        // A ramp, not DC: an off-by-one read or a reversed span is invisible in a constant.
+        for (std::size_t i = 0; i < s.frames.size(); ++i)
+            s.frames[i] = static_cast<float>(i) / 4000.f - 0.5f;
+        s.sampleRate = kRate;
+        s.rootNote = 60;
+        s.play.playMode = PlayMode::Trigger;
+        s.play.pitchEngine = PitchEngine::Varispeed;
+
+        // Shorter than the play span, so the window closes before any note-end shaping.
+        const BakePlan plan = planOf(/*total=*/1000, /*noteOn=*/0, /*noteOff=*/1000);
+        const BakeAudio audio = renderBake(s, plan, kUnity);
+        CHECK(audio.channelCount == 1);
+        CHECK(audio.frameCount() == 1000);
+
+        bool identity = audio.frameCount() == 1000;
+        for (std::size_t f = 0; identity && f < 1000; ++f)
+            identity = (audio.interleaved[f] == s.frames[f]);
+        CHECK(identity);
+
+        // …and the gain rides that as an exact scalar, which is the only other thing the
+        // render is permitted to do to the signal.
+        const BakeAudio halved = renderBake(s, plan, 0.5);
+        bool scaled = halved.frameCount() == 1000;
+        for (std::size_t f = 0; scaled && f < 1000; ++f)
+            scaled = (halved.interleaved[f] == s.frames[f] * 0.5f);
+        CHECK(scaled);
+    }
+
     // --- Refusals -----------------------------------------------------------------------
     {
         SampleData empty;  // nothing decoded

tests/test_bake_reset.cpp

@@ -4,20 +4,34 @@
 // Covers the ratified reset scope PER PARAMETER, in both directions: every control whose
 // effect the render printed comes back at its default, and every mapping fact comes back
 // untouched. Asserted field by field rather than by struct equality on purpose — a
-// whole-struct compare would pass while silently resetting a survivor, or vice versa.
+// whole-struct compare would pass while silently resetting a survivor, or vice versa. The
+// sweep runs over TWO independently dialed fixtures that share only the survivors, which is
+// what makes it a property of the survivors alone rather than of one input.
 
 #include "../src/core/instrument/bake/bake_reset.h"
 
+// The loop's neutral is loop_marks' definition of it, not this test's reading of it: what a
+// reset loop LOOKS like on the band is the thing worth asserting, and only that module says.
+#include "../src/core/instrument/ui/loop_marks.h"
+
 #include <cstdio>
+#include <optional>
 
 using namespace reasampler;
 using namespace reasampler::instrument::bake;
 using reasampler::instrument::map::InstrumentParams;
 using reasampler::instrument::map::PlaySeconds;
+using reasampler::instrument::ui::LoopMarks;
+using reasampler::instrument::ui::StoredLoop;
+using reasampler::instrument::ui::resolveLoopMarks;
+
+namespace note = reasampler::instrument::note;
+namespace filter = reasampler::instrument::engine::filter;
 
 static int g_fail = 0;
+static const char* g_ctx = "";
 #define CHECK(cond) do { if(!(cond)) { \
-    std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)
+    std::printf("FAIL [%s] line %d: %s\n", g_ctx, __LINE__, #cond); ++g_fail; } } while(0)
 
 namespace {
 
@@ -45,14 +59,18 @@ InstrumentParams dialed() {
     p.play.trigAhd.decaySeconds = 0.22;
     p.play.trigAhd.holdFraction = 0.33;
     p.play.trigAhd.attackCurve = 1.7;
+    p.play.trigAhd.decayCurve = 2.2;
     p.play.pitchEngine = PitchEngine::Varispeed;
     p.play.pitchEnv.enabled = true;
     p.play.pitchEnv.peakSemitones = -7.0;
     p.play.pitchEnv.shape.attackSeconds = 0.05;
+    p.play.pitchEnv.shape.decaySeconds = 0.15;
     p.play.pitchVelocityCurve = VelocityCurve::linear();
     p.play.playRate = 0.5;
     p.play.pitchOffsetSemitones = -7.5;
     p.play.filter.enabled = true;
+    p.play.filter.settings = filter::FilterSettings{0.3f, 0.8f, 0.1f, 0.7f,
+                                                    filter::MorphLaw::HighNotchLow};
     p.play.filter.modAmount = -0.8;
     p.play.filter.velAmount = 0.6;
     p.play.filter.keyTrack = 1.5;
@@ -62,7 +80,69 @@ InstrumentParams dialed() {
     p.play.ampSpline.mode = EnvMode::Spline;
     p.play.ampSpline.contour = VelocityCurve::linear();
     p.play.pitchSpline.mode = EnvMode::Spline;
+    p.play.pitchSpline.contour = VelocityCurve::linear();
     p.play.filterSpline.mode = EnvMode::Spline;
+    p.play.filterSpline.contour = VelocityCurve::linear();
+    p.bakeHold = note::makeDivision(0, note::DivisionModifier::Dotted);
+    p.limiterEnabled = true;
+    return p;
+}
+
+// A SECOND dialed instrument, agreeing with the first on the SURVIVORS and disagreeing on
+// every other field — including play mode, which is a chosen neutral rather than a survivor.
+// Both run the same neutral sweep: if the reset ever inverted into "copy the dialed set, then
+// clear a blacklist", a non-survivor would come through and at most one fixture could still
+// land on the defaults. A parameter added later is covered here by moving it in BOTH
+// fixtures, which is the same work as adding it to the sweep.
+InstrumentParams dialedOther() {
+    InstrumentParams p;
+    p.rootOverride = 43;   // survivor — same as dialed()
+    p.keyTrack = 0.5;      // survivor — same as dialed()
+    p.loopOverride = SampleLoop{true, 7, 909};
+    p.startPoint = 12;
+    p.loopCrossfadeFrames = 64;
+    p.velocityCurve = VelocityCurve::rampDown();
+
+    p.play.playMode = PlayMode::Gate;
+    p.play.adsr.attackSeconds = 1.4;
+    p.play.adsr.holdSeconds = 1.3;
+    p.play.adsr.decaySeconds = 1.2;
+    p.play.adsr.sustainLevel = 0.7;
+    p.play.adsr.releaseSeconds = 1.9;
+    p.play.adsr.attackCurve = 0.3;
+    p.play.adsr.decayCurve = 3.4;
+    p.play.adsr.releaseCurve = 0.6;
+    p.play.trigger.lengthFraction = 0.75;
+    p.play.trigAhd.attackSeconds = 0.91;
+    p.play.trigAhd.decaySeconds = 0.82;
+    p.play.trigAhd.holdFraction = 0.13;
+    p.play.trigAhd.attackCurve = 0.7;
+    p.play.trigAhd.decayCurve = 0.9;
+    p.play.pitchEngine = PitchEngine::Preserve;
+    p.play.pitchEnv.enabled = true;
+    p.play.pitchEnv.peakSemitones = 11.0;
+    p.play.pitchEnv.shape.attackSeconds = 0.25;
+    p.play.pitchEnv.shape.decaySeconds = 0.35;
+    p.play.pitchVelocityCurve = VelocityCurve::rampDown();
+    p.play.playRate = 1.75;
+    p.play.pitchOffsetSemitones = 3.25;
+    p.play.filter.enabled = true;
+    p.play.filter.settings = filter::FilterSettings{0.9f, 0.2f, 0.4f, 0.05f,
+                                                    filter::MorphLaw::HighNotchLow};
+    p.play.filter.modAmount = 0.45;
+    p.play.filter.velAmount = -0.35;
+    p.play.filter.keyTrack = -0.9;
+    p.play.filter.env.attackSeconds = 1.7;
+    p.play.filter.trigEnv.decaySeconds = 1.8;
+    p.play.filter.velocityCurve = VelocityCurve::rampDown();
+    p.play.ampSpline.mode = EnvMode::Spline;
+    p.play.ampSpline.contour = VelocityCurve::flat();
+    p.play.pitchSpline.mode = EnvMode::Spline;
+    p.play.pitchSpline.contour = VelocityCurve::flat();
+    p.play.filterSpline.mode = EnvMode::Spline;
+    p.play.filterSpline.contour = VelocityCurve::flat();
+    p.bakeHold = note::makeDivision(2, note::DivisionModifier::Triplet);
+    p.limiterEnabled = true;
     return p;
 }
 
@@ -75,22 +155,13 @@ bool sameCurve(const VelocityCurve& a, const VelocityCurve& b) {
     return true;
 }
 
-}  // namespace
+// THE reset neutral, field by field. Run against every fixture, so the two can never be
-
+// asserted against two different notions of neutral.
-int main() {
+void checkNeutral(const BakeReset& reset) {
-    const InstrumentParams before = dialed();
-    const BakeReset reset = resetAfterBake(before);
     const InstrumentParams& after = reset.params;
     const InstrumentParams fresh;      // the defaults every reset control must land on
     const PlaySeconds freshPlay;
 
-    // --- SURVIVE: mapping facts, absent from the printed audio ----------------------
-    CHECK(after.rootOverride.has_value());
-    CHECK(after.rootOverride == before.rootOverride);
-    CHECK(after.keyTrack == before.keyTrack);
-    CHECK(after.keyTrack == 0.5);      // and it is the dialed value, not the default 1.0
-    CHECK(fresh.keyTrack != before.keyTrack);  // the fixture really did move it
-
     // --- RESET: loop points, start point, crossfade ---------------------------------
     CHECK(!after.loopOverride.has_value());
     CHECK(!after.startPoint.has_value());
@@ -98,26 +169,17 @@ int main() {
 
     // --- RESET: the velocity transfer curves ----------------------------------------
     CHECK(sameCurve(after.velocityCurve, VelocityCurve::flat()));
-    CHECK(!sameCurve(after.velocityCurve, before.velocityCurve));
     CHECK(sameCurve(after.play.pitchVelocityCurve, VelocityCurve::zero()));
     CHECK(sameCurve(after.play.filter.velocityCurve, VelocityCurve::zero()));
 
     // --- RESET: play mode, to TRIGGER rather than to the struct's Gate default -------
-    // The bake's product is a finished one-shot; Trigger plays it back verbatim, Gate would
+    // bake_reset.cpp carries the argument at the assignment.
-    // re-gate its printed release tail and each iteration would truncate the last one's.
     CHECK(after.play.playMode == PlayMode::Trigger);
     CHECK(freshPlay.playMode == PlayMode::Gate);  // and that really is NOT the default
     // The Trigger face it lands on plays the whole file flat: full span, unity throughout.
     CHECK(after.play.trigger.lengthFraction == 1.0);
     CHECK(after.play.trigAhd.attackSeconds == 0.0);
     CHECK(after.play.trigAhd.decaySeconds == 0.0);
-    {
-        // …and a GATE-dialed instrument lands there too: this is a reset to a chosen
-        // neutral, not the dialed value surviving.
-        InstrumentParams gated = dialed();
-        gated.play.playMode = PlayMode::Gate;
-        CHECK(resetAfterBake(gated).params.play.playMode == PlayMode::Trigger);
-    }
 
     // --- RESET: the amp envelope, staged, every stage and every curve exponent ------
     CHECK(after.play.adsr.attackSeconds == freshPlay.adsr.attackSeconds);
@@ -133,6 +195,7 @@ int main() {
     CHECK(after.play.trigAhd.decaySeconds == freshPlay.trigAhd.decaySeconds);
     CHECK(after.play.trigAhd.holdFraction == freshPlay.trigAhd.holdFraction);
     CHECK(after.play.trigAhd.attackCurve == freshPlay.trigAhd.attackCurve);
+    CHECK(after.play.trigAhd.decayCurve == freshPlay.trigAhd.decayCurve);
 
     // --- RESET: pitch engine + pitch envelope ---------------------------------------
     CHECK(after.play.pitchEngine == freshPlay.pitchEngine);
@@ -140,6 +203,7 @@ int main() {
     CHECK(!after.play.pitchEnv.enabled);
     CHECK(after.play.pitchEnv.peakSemitones == 0.0);
     CHECK(after.play.pitchEnv.shape.attackSeconds == freshPlay.pitchEnv.shape.attackSeconds);
+    CHECK(after.play.pitchEnv.shape.decaySeconds == freshPlay.pitchEnv.shape.decaySeconds);
 
     // --- RESET: Rate and the baseline Pitch offset -----------------------------------
     // Both are processing the bake already printed, so the whitelist leaves them at their
@@ -150,11 +214,16 @@ int main() {
     CHECK(after.play.playRate == freshPlay.playRate);
     CHECK(after.play.pitchOffsetSemitones == freshPlay.pitchOffsetSemitones);
 
-    // --- RESET: the filter, including its velocity/key-tracking mod -----------------
+    // --- RESET: the filter, its control positions, and its velocity/key-tracking mod --
     CHECK(!after.play.filter.enabled);
     CHECK(after.play.filter.modAmount == 0.0);
     CHECK(after.play.filter.velAmount == 0.0);
     CHECK(after.play.filter.keyTrack == 0.0);
+    CHECK(after.play.filter.settings.cutoffNorm == freshPlay.filter.settings.cutoffNorm);
+    CHECK(after.play.filter.settings.resonanceNorm == freshPlay.filter.settings.resonanceNorm);
+    CHECK(after.play.filter.settings.morphNorm == freshPlay.filter.settings.morphNorm);
+    CHECK(after.play.filter.settings.driveNorm == freshPlay.filter.settings.driveNorm);
+    CHECK(after.play.filter.settings.morphLaw == freshPlay.filter.settings.morphLaw);
     CHECK(after.play.filter.env.attackSeconds == freshPlay.filter.env.attackSeconds);
     CHECK(after.play.filter.trigEnv.decaySeconds == freshPlay.filter.trigEnv.decaySeconds);
 
@@ -165,10 +234,94 @@ int main() {
     CHECK(after.play.pitchSpline.mode == EnvMode::Staged);
     CHECK(after.play.filterSpline.mode == EnvMode::Staged);
     CHECK(sameCurve(after.play.ampSpline.contour, VelocityCurve::rampDown()));
-    CHECK(!sameCurve(after.play.ampSpline.contour, before.play.ampSpline.contour));
+    CHECK(sameCurve(after.play.pitchSpline.contour, VelocityCurve::rampDown()));
+    CHECK(sameCurve(after.play.filterSpline.contour, VelocityCurve::rampDown()));
+
+    // --- RESET: the bake's own Hold division -----------------------------------------
+    // It sizes the render window for the one case that cannot derive one, so the length it
+    // chose is in the printed file, and the next bake re-derives from that file.
+    CHECK(after.bakeHold == fresh.bakeHold);
+
+    // --- RESET: the master-bus limiter enable ----------------------------------------
+    // Read the asymmetry recorded at BakeReset before reasoning about this one: it is not
+    // the master stage resetting as a unit.
+    CHECK(!after.limiterEnabled);
+    CHECK(!fresh.limiterEnabled);
 
     // --- RESET: master gain ----------------------------------------------------------
     CHECK(reset.masterGainLinear == 1.0);
+}
+
+}  // namespace
+
+int main() {
+    const InstrumentParams before = dialed();
+    const BakeReset reset = resetAfterBake(before);
+    const InstrumentParams& after = reset.params;
+    const InstrumentParams fresh;
+
+    // The fixtures must really move every field the sweep asserts, or the sweep is vacuous.
+    CHECK(fresh.keyTrack != before.keyTrack);
+    CHECK(before.limiterEnabled != fresh.limiterEnabled);
+    CHECK(before.bakeHold != fresh.bakeHold);
+    CHECK(dialedOther().bakeHold != fresh.bakeHold);
+    CHECK(dialedOther().bakeHold != before.bakeHold);
+    CHECK(!sameCurve(before.velocityCurve, VelocityCurve::flat()));
+    CHECK(!sameCurve(before.play.ampSpline.contour, VelocityCurve::rampDown()));
+    CHECK(!sameCurve(dialedOther().play.ampSpline.contour, VelocityCurve::rampDown()));
+
+    // --- SURVIVE: mapping facts, absent from the printed audio ----------------------
+    CHECK(after.rootOverride.has_value());
+    CHECK(after.rootOverride == before.rootOverride);
+    CHECK(after.keyTrack == before.keyTrack);
+    CHECK(after.keyTrack == 0.5);      // and it is the dialed value, not the default 1.0
+
+    // --- The neutral, over both fixtures --------------------------------------------
+    g_ctx = "dialed";
+    checkNeutral(reset);
+    g_ctx = "dialedOther";
+    {
+        const BakeReset other = resetAfterBake(dialedOther());
+        checkNeutral(other);
+        // The survivors travel from the OTHER fixture too, so the sweep above is agreeing
+        // with a reset that read its input rather than one that ignores it wholesale.
+        CHECK(other.params.rootOverride == before.rootOverride);
+        CHECK(other.params.keyTrack == before.keyTrack);
+    }
+    g_ctx = "";
+
+    // --- A GATE-dialed instrument lands on Trigger too -------------------------------
+    // This is a reset to a chosen neutral, not the dialed value surviving.
+    {
+        InstrumentParams gated = dialed();
+        gated.play.playMode = PlayMode::Gate;
+        CHECK(resetAfterBake(gated).params.play.playMode == PlayMode::Trigger);
+    }
+
+    // --- The loop enable and its points come back together ---------------------------
+    // What the band shows after a bake is the reset override read against the newly banked
+    // entry, which carries NO loop intrinsic (the shell records that pairing where it builds
+    // the entry) — so the enable has nothing left to fall back to.
+    {
+        constexpr std::int64_t kFrames = 1000;
+        const LoopMarks dialedMarks =
+            resolveLoopMarks(StoredLoop{before.loopOverride, std::nullopt,
+                                        before.loopCrossfadeFrames, before.startPoint},
+                             kFrames);
+        CHECK(dialedMarks.hasLoop);        // the fixture really did dial a loop on…
+        CHECK(!dialedMarks.parked);        // …at its own positions
+        CHECK(dialedMarks.crossfade == 512);
+
+        const LoopMarks neutral =
+            resolveLoopMarks(StoredLoop{after.loopOverride, std::nullopt,
+                                        after.loopCrossfadeFrames, after.startPoint},
+                             kFrames);
+        CHECK(!neutral.hasLoop);
+        CHECK(neutral.parked);             // re-offered on the defaults, not left coincident
+        CHECK(neutral.loopStart < neutral.loopEnd);
+        CHECK(neutral.crossfade == 0);
+        CHECK(neutral.start == 0);
+    }
 
     // --- An absent root override stays absent (nothing is invented) ------------------
     {