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reasampler/tests/test_sampler_core.cpp
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daniel 9d38f87a2d instrument: one VELOCITY deck for all three velocity curves, bipolar and off by default for pitch and filter 
Payload v12 appends the new velocity->pitch curve and folds the retired filter velAmount into its now-bipolar curve, so pre-v12 projects reopen sounding identical. Preview button takes a drawn play triangle.
2026-07-31 19:15:17 -04:00

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// Standalone tests for reasampler::sampler_core — no VST3, no REAPER, no test
// framework. Same fast build/run loop as bank_model_tests / peaks_tests: feed known
// inputs, assert the engine's behavior.
//
// Covers (PLAN.md S3 / CONTEXT.md §Phase S pure core):
// 1. polyphonic allocation — N notes -> N voices; note-off releases the right voice.
// 2. voice stealing at the bound — deterministic policy (release-first, then oldest).
// 3. ADSR envelope shape vs a known signal, incl. release-before-sustain.
// 4. repitch ratio correctness across +/-1 octave from root incl. unity, asserted on
// the observed period of a synthesized sine.
// 5. loop-point sustain — held note past sample end loops [start,end) seamlessly;
// zero-length loop and absent-loop behavior.
// 6. keymap: chromatic-from-single-root; zoned ranges with boundary notes; velocity
// -> volume; out-of-zone note -> defined no-play.
//
// The plain-data boundary (no VST3/REAPER types in the core) is enforced STRUCTURALLY
// by the CMake target linking neither SDK — this file includes only sampler_core.h +
// the standard library, which is itself the compile-time proof.
#include "../src/core/instrument/engine/voice_engine.h"
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <vector>
using namespace reasampler;
using namespace reasampler::instrument::engine;
static int g_fail = 0;
#define CHECK(cond) do { if(!(cond)) { \
std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)
static bool approx(double a, double b, double tol) { return std::fabs(a - b) <= tol; }
constexpr double kPi = 3.14159265358979323846;
// A silent (all-1.0) sample so a rendered voice's output tracks the envelope * velocity
// directly (DC of amplitude 1). Root at note 60 by default.
static SampleData dcSample(std::size_t frames, int rootNote = 60) {
SampleData s;
s.frames.assign(frames, 1.0f);
s.rootNote = rootNote;
return s;
}
// A mono sine of `cycles` periods over `frames` frames — used to observe repitch by
// measuring the played-back period.
static SampleData sineSample(std::size_t frames, double cycles, int rootNote = 60) {
SampleData s;
s.frames.resize(frames);
for (std::size_t i = 0; i < frames; ++i) {
s.frames[i] = static_cast<float>(std::sin(2.0 * kPi * cycles *
static_cast<double>(i) / static_cast<double>(frames)));
}
s.rootNote = rootNote;
return s;
}
// An ADSR that stays fully open (level 1) forever while held, so voice output equals
// velocity gain — isolates allocation/repitch/loop tests from envelope shaping.
static AdsrParams flatAdsr() {
AdsrParams a;
a.attackFrames = 0;
a.decayFrames = 0;
a.sustainLevel = 1.0;
a.releaseFrames = 0; // note-off -> instant silence.
return a;
}
// ---------------------------------------------------------------------------
// 6. Full-keyboard response over the one loaded capture.
// ---------------------------------------------------------------------------
static void testEveryKeyPlaysTheLoadedCapture() {
// No key range survives: the loaded capture answers every note in 0..127, repitched
// from its root. Each note-on must take a real voice.
SampleData km = dcSample(100, 60);
VoiceEngine eng(128, km);
for (int n = 0; n <= 127; ++n) {
CHECK(eng.noteOn(n, 100) != VoiceEngine::kNoVoice);
}
CHECK(eng.activeVoiceCount() == 128);
}
static void testUnplayableCaptureRefusesEveryNote() {
// Nothing decoded -> the defined no-play at every key, in both voice modes, rather
// than a voice started on an empty read span.
SampleData empty; // no frames
VoiceEngine poly(4, empty);
CHECK(poly.noteOn(60, 100) == VoiceEngine::kNoVoice);
CHECK(poly.noteOn(0, 100) == VoiceEngine::kNoVoice);
CHECK(poly.activeVoiceCount() == 0);
VoiceEngine mono(4, empty, 0, 0, VoiceMode::Mono);
CHECK(mono.noteOn(60, 100) == VoiceEngine::kNoVoice);
CHECK(mono.activeVoiceCount() == 0);
}
static void testOutOfRangeNotesAreRefusedInMono() {
// The mono held stack keys notes as uint8, so an out-of-range note must be rejected
// BEFORE it can alias onto a real held note.
SampleData km = dcSample(100, 60);
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono);
CHECK(eng.noteOn(-1, 100) == VoiceEngine::kNoVoice);
CHECK(eng.noteOn(128, 100) == VoiceEngine::kNoVoice);
CHECK(eng.activeVoiceCount() == 0);
}
// ---------------------------------------------------------------------------
// 4. Repitch ratio correctness.
// ---------------------------------------------------------------------------
static void testPitchRatioMath() {
CHECK(approx(pitchRatio(60, 60), 1.0, 1e-9)); // unity at root
CHECK(approx(pitchRatio(72, 60), 2.0, 1e-9)); // +1 octave
CHECK(approx(pitchRatio(48, 60), 0.5, 1e-9)); // -1 octave
CHECK(approx(pitchRatio(61, 60), std::pow(2.0, 1.0 / 12.0), 1e-9)); // +1 semitone
}
// --- S-VIEW-6 key-tracking ratio math (pure), asserted at 0 / 100 / 200% + off-root. ---
static void testKeyTrackedRatioMath() {
// 100% (keyTrack == 1.0) is standard 12-tone-ET and BIT-IDENTICAL to pitchRatio: the argument
// to std::pow is (note-root)*1.0, exact in IEEE-754, so the same call yields the same bits.
for (int note = 0; note <= 127; ++note) {
CHECK(keyTrackedRatio(note, 60, 1.0) == pitchRatio(note, 60)); // exact equality, not approx
}
CHECK(approx(keyTrackedRatio(72, 60, 1.0), 2.0, 1e-9)); // +1 octave tracked normally
CHECK(approx(keyTrackedRatio(48, 60, 1.0), 0.5, 1e-9)); // -1 octave tracked normally
// 0% (keyTrack == 0.0): no tracking. Every key — including off-root ones — plays root pitch.
CHECK(approx(keyTrackedRatio(60, 60, 0.0), 1.0, 1e-12)); // at root: unity (trivially)
CHECK(approx(keyTrackedRatio(72, 60, 0.0), 1.0, 1e-12)); // an octave up STILL plays root pitch
CHECK(approx(keyTrackedRatio(48, 60, 0.0), 1.0, 1e-12)); // an octave down STILL plays root pitch
CHECK(approx(keyTrackedRatio(67, 60, 0.0), 1.0, 1e-12)); // an off-root 5th STILL plays root pitch
// 200% (keyTrack == 2.0): double-rate tracking. The semitone offset is doubled, so a +12 key
// plays as if +24 (two octaves, ratio 4.0), a -12 key as -24 (ratio 0.25).
CHECK(approx(keyTrackedRatio(72, 60, 2.0), 4.0, 1e-9)); // +12 -> +24 semis -> 4.0
CHECK(approx(keyTrackedRatio(48, 60, 2.0), 0.25, 1e-9)); // -12 -> -24 semis -> 0.25
CHECK(approx(keyTrackedRatio(60, 60, 2.0), 1.0, 1e-12)); // root is unity at ANY keyTrack
// Off-root at 200% for a single semitone: +1 semi -> +2 semis -> 2^(2/12).
CHECK(approx(keyTrackedRatio(61, 60, 2.0), std::pow(2.0, 2.0 / 12.0), 1e-9));
// An arbitrary intermediate scalar (50%): +12 key tracks as +6 semis -> 2^(6/12) = sqrt(2).
CHECK(approx(keyTrackedRatio(72, 60, 0.5), std::pow(2.0, 6.0 / 12.0), 1e-9));
}
// Observe repitch on the rendered signal: a voice played an octave above root should
// advance through the sample twice as fast, so a sine's observed period halves. We
// measure the period by counting the interval between positive-going zero crossings.
static double observedPeriodFrames(const std::vector<AudioSample>& out) {
std::vector<std::size_t> upCrossings;
for (std::size_t i = 1; i < out.size(); ++i) {
if (out[i - 1] <= 0.0f && out[i] > 0.0f) upCrossings.push_back(i);
}
if (upCrossings.size() < 2) return 0.0;
// Average spacing between crossings.
double sum = 0.0;
for (std::size_t i = 1; i < upCrossings.size(); ++i) {
sum += static_cast<double>(upCrossings[i] - upCrossings[i - 1]);
}
return sum / static_cast<double>(upCrossings.size() - 1);
}
static void testRepitchObservedPeriod() {
// A sine of 20 cycles over 8000 frames -> native period 400 frames at unity.
const std::size_t frames = 8000;
const double cycles = 20.0;
const double nativePeriod = static_cast<double>(frames) / cycles; // 400
// Unity: played at root, observed period ~= native.
{
SampleData km = (sineSample(frames, cycles, 60));
VoiceEngine eng(4, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, frames);
double p = observedPeriodFrames(out);
CHECK(approx(p, nativePeriod, 2.0));
}
// +1 octave: advances 2x, observed period halves.
{
SampleData km = (sineSample(frames, cycles, 60));
VoiceEngine eng(4, km);
eng.noteOn(72, 127);
std::vector<AudioSample> out;
eng.render(out, frames / 2); // half as many frames covers the whole sample
double p = observedPeriodFrames(out);
CHECK(approx(p, nativePeriod / 2.0, 2.0));
}
// -1 octave: advances 0.5x, observed period doubles.
{
SampleData km = (sineSample(frames, cycles, 60));
VoiceEngine eng(4, km);
eng.noteOn(48, 127);
std::vector<AudioSample> out;
eng.render(out, frames);
double p = observedPeriodFrames(out);
CHECK(approx(p, nativePeriod * 2.0, 4.0));
}
}
// --- S-VIEW-6 keyTrack reaches the VARISPEED engine: observed period tracks the scalar. ---
static void testKeyTrackVarispeedObservedPeriod() {
const std::size_t frames = 8000;
const double cycles = 20.0;
const double nativePeriod = static_cast<double>(frames) / cycles; // 400 at unity
auto periodAt = [&](int note, double keyTrack) -> double {
SampleData s = sineSample(frames, cycles, 60);
s.play.pitchEngine = PitchEngine::Varispeed;
SampleData km = (std::move(s));
// The single zone spans the keyboard from root 60; stamp the key-track scalar on it.
km.keyTrack = keyTrack;
VoiceEngine eng(4, km);
eng.noteOn(note, 127);
std::vector<AudioSample> out;
eng.render(out, frames);
return observedPeriodFrames(out);
};
// note 72 (+1 octave). At 100% it plays an octave up (period halves ~200). At 0% it plays at
// ROOT pitch (period ~native 400 — no tracking). The observed periods must differ by ~2x, which
// proves the scalar drove the Varispeed read rate.
const double at100 = periodAt(72, 1.0);
const double at0 = periodAt(72, 0.0);
CHECK(approx(at100, nativePeriod / 2.0, 3.0)); // 100%: tracked an octave up
CHECK(approx(at0, nativePeriod, 3.0)); // 0%: no tracking, plays root pitch
}
// --- S-VIEW-6 keyTrack reaches the PRESERVE engine: at 0% an off-root note collapses to the root
// shift (unity), producing output identical to playing the root note. Proves keyTrack feeds
// baseRatio_ -> the Preserve shift amount (not merely the Varispeed read rate). ---
static void testKeyTrackPreserveShiftCollapsesAtZero() {
const std::size_t frames = 2000;
const std::size_t window = 512;
const double cycles = 40.0;
auto renderPreserve = [&](int note, double keyTrack) -> std::vector<AudioSample> {
SampleData s = sineSample(frames, cycles, 60);
s.play.pitchEngine = PitchEngine::Preserve; // Gate, no loop -> runs to sample end
SampleData km = (std::move(s));
km.keyTrack = keyTrack;
VoiceEngine eng(1, km, /*preserveCap=*/0, static_cast<std::int64_t>(window));
eng.noteOn(note, 127);
std::vector<AudioSample> out;
eng.render(out, frames);
return out;
};
// An off-root note (+7) at keyTrack 0.0 sets the Preserve shift to the root ratio (1.0) — the
// shifter is pass-through, so the output must be BIT-IDENTICAL to playing the ROOT note (whose
// offset is 0, also shift 1.0). If keyTrack only touched Varispeed, these would differ.
const std::vector<AudioSample> offRootNoTrack = renderPreserve(67, 0.0);
const std::vector<AudioSample> rootRef = renderPreserve(60, 1.0);
CHECK(offRootNoTrack.size() == rootRef.size());
bool identical = offRootNoTrack.size() == rootRef.size();
for (std::size_t i = 0; i < offRootNoTrack.size() && identical; ++i) {
if (offRootNoTrack[i] != rootRef[i]) identical = false;
}
CHECK(identical); // 0% tracking collapses the Preserve shift to unity, exactly like the root
}
// ---------------------------------------------------------------------------
// 3. ADSR envelope shape vs a known signal.
// ---------------------------------------------------------------------------
static void testAdsrShape() {
AdsrParams p;
p.attackFrames = 10;
p.decayFrames = 10;
p.sustainLevel = 0.5;
p.releaseFrames = 10;
AdsrEnvelope env;
env.configure(p);
env.noteOn();
// Attack: 0 -> ramps up. Frame 0 == 0, rising each frame.
double prev = -1.0;
for (int i = 0; i < 10; ++i) {
double v = env.tick();
CHECK(v >= prev); // monotonic non-decreasing through attack
CHECK(v >= 0.0 && v <= 1.0);
prev = v;
}
// Decay: from 1.0 down toward sustain 0.5, monotonic non-increasing.
prev = 2.0;
for (int i = 0; i < 10; ++i) {
double v = env.tick();
CHECK(v <= prev + 1e-9); // non-increasing through decay
CHECK(v >= 0.5 - 1e-9); // never below sustain during decay
prev = v;
}
// Sustain: holds 0.5 indefinitely.
for (int i = 0; i < 100; ++i) {
CHECK(approx(env.tick(), 0.5, 1e-9));
}
CHECK(env.stage() == AdsrEnvelope::Stage::Sustain);
// Release: 0.5 -> 0 over 10 frames, then Finished + latched at 0.
env.noteOff();
prev = 1.0;
for (int i = 0; i < 10; ++i) {
double v = env.tick();
CHECK(v <= prev + 1e-9); // non-increasing through release
prev = v;
}
CHECK(env.finished());
for (int i = 0; i < 10; ++i) CHECK(approx(env.tick(), 0.0, 1e-12));
}
static void testAdsrReleaseBeforeSustain() {
// noteOff during the attack ramp releases from the PARTIAL level, not sustain.
AdsrParams p;
p.attackFrames = 100;
p.decayFrames = 10;
p.sustainLevel = 0.8;
p.releaseFrames = 20;
AdsrEnvelope env;
env.configure(p);
env.noteOn();
// Advance 50 frames into a 100-frame attack -> partial level ~0.5.
double last = 0.0;
for (int i = 0; i < 50; ++i) last = env.tick();
CHECK(last > 0.3 && last < 0.7); // partway up the attack ramp
CHECK(env.stage() == AdsrEnvelope::Stage::Attack);
env.noteOff();
CHECK(env.stage() == AdsrEnvelope::Stage::Release);
// First release frame must be at or below the partial level we left off at —
// NOT jump up to sustain 0.8. This is the release-before-sustain guarantee.
double firstRelease = env.tick();
CHECK(firstRelease <= last + 1e-9);
CHECK(firstRelease < p.sustainLevel); // proves it did not snap to sustain
// Decays to zero.
double prev = firstRelease;
for (int i = 0; i < 20; ++i) {
double v = env.tick();
CHECK(v <= prev + 1e-9);
prev = v;
}
CHECK(env.finished());
}
static void testAdsrZeroAttackDecay() {
// Zero attack + zero decay -> jumps straight to sustain on the first ticks.
AdsrParams p;
p.attackFrames = 0;
p.decayFrames = 0;
p.sustainLevel = 0.7;
p.releaseFrames = 5;
AdsrEnvelope env;
env.configure(p);
env.noteOn();
// Zero attack emits the attack peak (1.0) on frame 0 and immediately transitions
// through the (also zero-length) decay, so by frame 1 the envelope is holding
// sustain. The peak-at-boundary is the documented single-frame edge, not a bug.
CHECK(approx(env.tick(), 1.0, 1e-9)); // frame 0: attack peak
CHECK(approx(env.tick(), 0.7, 1e-9)); // frame 1: sustain
CHECK(approx(env.tick(), 0.7, 1e-9));
CHECK(env.stage() == AdsrEnvelope::Stage::Sustain);
}
// ---------------------------------------------------------------------------
// 1. Polyphonic allocation + note-off routing.
// ---------------------------------------------------------------------------
static void testPolyphonicAllocation() {
SampleData km = (dcSample(1000, 60));
VoiceEngine eng(8, km);
// Four simultaneous notes -> four active voices, each on a distinct voice.
std::size_t v60 = eng.noteOn(60, 100);
std::size_t v64 = eng.noteOn(64, 100);
std::size_t v67 = eng.noteOn(67, 100);
std::size_t v72 = eng.noteOn(72, 100);
CHECK(v60 != VoiceEngine::kNoVoice);
CHECK(eng.activeVoiceCount() == 4);
CHECK(v60 != v64 && v64 != v67 && v67 != v72 && v60 != v72);
// Note-off on 64 releases exactly one voice; with instant release it goes idle
// after the next render frame.
eng.noteOff(64);
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(eng.activeVoiceCount() == 3);
// The still-held notes keep sounding.
eng.render(out, 1);
CHECK(eng.activeVoiceCount() == 3);
}
static void testNoteOffReleasesNewestSameNote() {
// Prove that noteOff releases the NEWEST (highest startOrder) instance of a
// re-triggered note, leaving the older voice in sustain.
//
// Two voices at distinct velocities so their output is distinguishable:
// "first" (older) -> velocity 64 -> gain ~0.504 (G_old)
// "second" (newer) -> velocity 127 -> gain 1.0 (G_new)
//
// With a DC-1 sample and sustain=1, while both are held:
// render sum == G_old + G_new.
//
// After noteOff (must release newest), the newer voice enters a short release.
// Render past releaseFrames: newer voice finishes; only the older voice remains.
// Sum then equals G_old, and activeVoiceCount drops to 1. If the WRONG voice
// were released, the older would finish and the remaining sum would equal G_new
// (1.0 vs ~0.504) — the velocities make the error distinguishable.
const int velOld = 64;
const int velNew = 127;
const double gainOld = velOld / 127.0; // ~0.504
const double gainNew = velNew / 127.0; // 1.0
SampleData sd = dcSample(100000, 60);
sd.play.adsr = flatAdsr();
sd.play.adsr.releaseFrames = 10; // short but non-zero so voice stays active through release
SampleData km = (sd);
// A LINEAR velocity curve keeps the two velocities distinguishable (velocity/127). The default
// flat y=1 curve (S-VIEW-9 R10-F1) would render both at unity, collapsing the distinction this
// note-off-selection test relies on — so we opt this zone back to the linear response.
km.velocityCurve = VelocityCurve::linear();
VoiceEngine eng(8, km);
std::size_t first = eng.noteOn(60, velOld); // older voice, lower gain
std::size_t second = eng.noteOn(60, velNew); // newer voice, higher gain
CHECK(first != second);
CHECK(eng.activeVoiceCount() == 2);
// While both are held, combined output equals gainOld + gainNew.
{
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(approx(out[0], gainOld + gainNew, 1e-4));
}
// Release once — must target the NEWEST voice (second).
eng.noteOff(60);
// Render past the release (releaseFrames == 10): newer voice goes Finished.
std::vector<AudioSample> out;
eng.render(out, 20);
// Newer voice must be done; only the older voice remains.
CHECK(eng.activeVoiceCount() == 1);
// Tail frames must equal gainOld (~0.504), NOT gainNew (1.0).
// If the older voice were released instead, the tail would be ~1.0 here.
for (std::size_t i = 15; i < out.size(); ++i) {
CHECK(approx(out[i], gainOld, 1e-4));
}
// A second note-off releases the remaining older voice.
eng.noteOff(60);
eng.render(out, 20);
CHECK(eng.activeVoiceCount() == 0);
}
// ---------------------------------------------------------------------------
// 2. Voice stealing at the bound.
// ---------------------------------------------------------------------------
static void testStealsReleasingVoiceFirst() {
// Long per-zone release so the voice stays active through the release tail. Voice::start reads
// sample.play.adsr (the engine holds no ADSR), so the long release lives on the SampleData.
SampleData s = dcSample(100000, 60);
s.play.adsr = flatAdsr();
s.play.adsr.releaseFrames = 100000; // long release so a released voice stays "active"
SampleData km = (std::move(s));
VoiceEngine eng(2, km);
std::size_t vA = eng.noteOn(60, 100); // startOrder 1
std::size_t vB = eng.noteOn(62, 100); // startOrder 2
CHECK(eng.activeVoiceCount() == 2);
// Release the NEWER voice (62) — it becomes the only releasing voice.
eng.noteOff(62);
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(eng.activeVoiceCount() == 2); // both still ringing (long release)
// A new note with the pool full must steal the RELEASING voice (vB), not the
// older held voice (vA) — release-first policy.
std::size_t vC = eng.noteOn(64, 100);
CHECK(vC == vB);
CHECK(eng.activeVoiceCount() == 2);
}
static void testStealsOldestWhenNoneReleasing() {
// 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;
SampleData km = (std::move(s));
VoiceEngine eng(2, km);
std::size_t vA = eng.noteOn(60, 100); // startOrder 1 (oldest)
std::size_t vB = eng.noteOn(62, 100); // startOrder 2
CHECK(vA != vB);
// No voice released; both held. A new note steals the OLDEST (vA).
std::size_t vC = eng.noteOn(64, 100);
CHECK(vC == vA);
CHECK(eng.activeVoiceCount() == 2);
// The stolen voice now carries note 64; a note-off on 60 (the stolen-away note)
// finds nothing to release.
std::size_t before = eng.activeVoiceCount();
eng.noteOff(60);
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(eng.activeVoiceCount() == before); // 60 no longer exists; no-op
}
// ---------------------------------------------------------------------------
// 5. Loop-point-aware sustain.
// ---------------------------------------------------------------------------
static void testLoopSustainSeamless() {
// A sample whose [0,20) frames are a distinctive ramp and [20,40) is a flat loop
// region of value 0.5. Held far past the sample end, the voice must keep emitting
// the loop region (0.5) rather than going silent.
SampleData s;
s.frames.resize(40);
for (int i = 0; i < 20; ++i) s.frames[i] = static_cast<float>(i) / 20.0f; // attack
for (int i = 20; i < 40; ++i) s.frames[i] = 0.5f; // loop body
s.rootNote = 60;
s.loop.hasLoop = true;
s.loop.start = 20;
s.loop.end = 40;
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // unity ratio, full velocity
std::vector<AudioSample> out;
eng.render(out, 200); // 5x the sample length
// Voice is still active (looping), not exhausted.
CHECK(eng.activeVoiceCount() == 1);
// Frames well past the loop start must sit at the loop body value 0.5.
for (std::size_t i = 60; i < out.size(); ++i) {
CHECK(approx(out[i], 0.5, 1e-4));
}
}
static void testZeroLengthLoopGoesSilent() {
// A zero-length loop (start == end) is the "no sustain" marker: the note runs off
// the sample end and the voice goes idle, rather than spinning on an empty span.
SampleData s = dcSample(50, 60); // 50 frames of 1.0
s.loop.hasLoop = true;
s.loop.start = 25;
s.loop.end = 25; // zero length
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 100); // past the 50-frame end
// After frame ~50 the voice should have gone idle (no loop to sustain it).
CHECK(eng.activeVoiceCount() == 0);
// Tail frames are silent.
for (std::size_t i = 60; i < out.size(); ++i) CHECK(approx(out[i], 0.0, 1e-6));
}
static void testSingleFrameLoop() {
// A loop of exactly one frame [start, start+1) — the narrowest valid loop.
// The path is correct-by-luck (loopLen = 1.0 divides evenly into any integer
// readPos advance at unity ratio), but Tier-2 tight loops make it load-bearing.
SampleData s;
s.frames.resize(10);
for (int i = 0; i < 10; ++i) s.frames[i] = static_cast<float>(i) * 0.1f;
s.rootNote = 60;
s.loop.hasLoop = true;
s.loop.start = 5;
s.loop.end = 6; // single-frame loop: [5, 6)
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // unity ratio, full velocity
std::vector<AudioSample> out;
eng.render(out, 50); // well past the sample end
// Voice must still be active — the single-frame loop keeps it alive.
CHECK(eng.activeVoiceCount() == 1);
// Every frame from the loop-start onward must be the value of frame 5 (0.5).
for (std::size_t i = 10; i < out.size(); ++i) {
CHECK(approx(out[i], 0.5, 1e-4));
}
}
static void testAbsentLoopGoesSilent() {
// No loop at all: held note runs off the end and goes idle (same as zero-length).
SampleData s = dcSample(50, 60);
// s.loop.hasLoop stays false.
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 100);
CHECK(eng.activeVoiceCount() == 0);
for (std::size_t i = 60; i < out.size(); ++i) CHECK(approx(out[i], 0.0, 1e-6));
}
// ---------------------------------------------------------------------------
// start point (S11): the voice's initial read position is SampleData::startFrame.
// ---------------------------------------------------------------------------
static void testStartFrameOffsetsInitialRead() {
// A per-frame ramp (frame i holds i*0.01) so the first rendered value pinpoints the
// read position. startFrame = 30 -> the first output frame reads frame 30 (0.30).
SampleData s;
s.frames.resize(100);
for (int i = 0; i < 100; ++i) s.frames[i] = static_cast<float>(i) * 0.01f;
s.rootNote = 60;
s.startFrame = 30;
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // unity ratio, full velocity, flat gain
std::vector<AudioSample> out;
eng.render(out, 3);
CHECK(approx(out[0], 0.30, 1e-4)); // starts at frame 30, not 0
CHECK(approx(out[1], 0.31, 1e-4)); // advances by unity ratio
CHECK(approx(out[2], 0.32, 1e-4));
}
static void testStartFrameZeroIsUnchanged() {
// startFrame default 0 is exactly the pre-S11 behavior: read begins at frame 0.
SampleData s;
s.frames.resize(20);
for (int i = 0; i < 20; ++i) s.frames[i] = static_cast<float>(i) * 0.05f;
s.rootNote = 60; // startFrame stays 0
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(approx(out[0], 0.0, 1e-6)); // frame 0
}
static void testStartFrameOutOfRangeClampsToZero() {
// A start point at/past the sample end degrades to frame 0 (play from the top), never an
// out-of-bounds read that would start the voice already exhausted.
SampleData s = dcSample(10, 60); // 10 frames of 1.0
s.startFrame = 10; // == frameCount: out of range
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 5);
// Reads from frame 0: the DC sample plays its 1.0 body rather than an immediate idle.
CHECK(eng.activeVoiceCount() == 1);
CHECK(approx(out[0], 1.0, 1e-4));
}
static void testStartFrameWithLoop() {
// Start point and loop compose: begin reading mid-sample, then sustain the loop region.
SampleData s;
s.frames.resize(40);
for (int i = 0; i < 40; ++i) s.frames[i] = static_cast<float>(i) * 0.01f;
for (int i = 20; i < 40; ++i) s.frames[i] = 0.5f; // loop body
s.rootNote = 60;
s.startFrame = 10; // begin at frame 10
s.loop.hasLoop = true;
s.loop.start = 20;
s.loop.end = 40;
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 200);
CHECK(approx(out[0], 0.10, 1e-4)); // started at frame 10
CHECK(eng.activeVoiceCount() == 1); // loop sustains it
for (std::size_t i = 60; i < out.size(); ++i) CHECK(approx(out[i], 0.5, 1e-4));
}
static void testStartAfterLoopEndWrapsIntoLoop() {
// Regression (S11 reviewer finding): if startFrame > loop.end (but still < frameCount),
// the voice's initial read head is past the loop end. The wrap-while in renderFrame must
// pull it back into [loopStart, loopEnd) on the very first frame, so the note sounds from
// somewhere inside the loop rather than running off the sample end silently.
//
// Setup: 100-frame sample; loop is [20, 40); startFrame = 60 (past loop.end = 40).
// loop body is a constant 0.5 so every frame inside it reads 0.5.
// After wrap: readPos starts inside [20, 40), first output frame == 0.5.
// Voice must stay active (loop sustains it) and emit the loop value, NOT go silent.
SampleData s;
s.frames.resize(100, 0.0f);
for (int i = 20; i < 40; ++i) s.frames[i] = 0.5f; // loop body
s.rootNote = 60;
s.startFrame = 60; // > loop.end (40), < frameCount (100)
s.loop.hasLoop = true;
s.loop.start = 20;
s.loop.end = 40;
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // unity ratio, full velocity
std::vector<AudioSample> out;
eng.render(out, 50);
// Voice must still be active — the usable loop keeps it alive indefinitely.
CHECK(eng.activeVoiceCount() == 1);
// Every frame after the first wrap must read 0.5 (the loop body). We skip the very
// first frame because the fractional-position wrap lands somewhere in [20,40) and the
// exact offset depends on how many loop lengths fit into 60; what matters is that the
// voice is alive and emitting the loop value, not 0.0 (pre-loop region).
for (std::size_t i = 5; i < out.size(); ++i) {
CHECK(approx(out[i], 0.5, 1e-4));
}
}
// ---------------------------------------------------------------------------
// Gate loop sustain: sample-exact wrapping, the crossfaded seam, and release out.
// ---------------------------------------------------------------------------
// A sample whose every frame carries its own index scaled down, so an observed output value
// names the exact source frame it came from — which is what makes "sample-exact" assertable
// rather than merely plausible.
static SampleData indexSample(std::size_t frames, int rootNote = 60) {
SampleData s;
s.frames.resize(frames);
for (std::size_t i = 0; i < frames; ++i) {
s.frames[i] = static_cast<float>(i) * 0.001f;
}
s.rootNote = rootNote;
return s;
}
// The source frame an output value names, inverted from indexSample's encoding.
static double sourceFrameOf(double out) { return out * 1000.0; }
static void testLoopReadWrapsSampleExactOverManyCycles() {
// Loop [40, 60) over a 100-frame index sample: the head must walk 40..59 and jump back to
// exactly 40, cycle after cycle, with nothing skipped or repeated at the seam.
SampleData s = indexSample(100);
s.loop.hasLoop = true;
s.loop.start = 40;
s.loop.end = 60;
s.play.adsr = flatAdsr();
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 200); // 8 full cycles past the loop entry
CHECK(eng.activeVoiceCount() == 1);
for (std::size_t i = 0; i < out.size(); ++i) {
// Output frame i reads source frame i while i < 60, then wraps by 20 each cycle.
const std::int64_t expected = i < 60 ? static_cast<std::int64_t>(i)
: 40 + ((static_cast<std::int64_t>(i) - 60) % 20);
CHECK(approx(sourceFrameOf(out[i]), static_cast<double>(expected), 1e-3));
}
}
static void testZeroCrossfadeLeavesTheSeamHard() {
// With no fade dialled, the frame at the loop end and the frame after it are the raw
// source frames — the step is the whole point of the default, and the whole thing a
// nonzero fade has to smooth.
SampleData s = indexSample(100);
s.loop.hasLoop = true;
s.loop.start = 40;
s.loop.end = 60;
s.loopCrossfadeFrames = 0;
s.play.adsr = flatAdsr();
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 80);
CHECK(approx(sourceFrameOf(out[59]), 59.0, 1e-3));
CHECK(approx(sourceFrameOf(out[60]), 40.0, 1e-3)); // hard jump, no blend
}
// The output at output-frame n, for loop [40,60) over the index sample under fade length xf.
static double loopedFrameValue(std::int64_t xf, std::size_t n) {
SampleData s = indexSample(100);
s.loop.hasLoop = true;
s.loop.start = 40;
s.loop.end = 60;
s.loopCrossfadeFrames = xf;
s.play.adsr = flatAdsr();
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 80);
return sourceFrameOf(out[n]);
}
static void testCrossfadeBlendsMonotonelyAcrossTheRegion() {
// Loop [40, 60) with an 8-frame pre-seam fade: over output frames 52..59 the read blends
// from source frame n toward source frame n-20 (the same head one loop length back). The
// region ENTRY is exactly continuous — frame 52 carries weight 0 — and every frame in it
// is the exact linear blend, falling monotonically.
SampleData s = indexSample(100);
s.loop.hasLoop = true;
s.loop.start = 40;
s.loop.end = 60;
s.loopCrossfadeFrames = 8;
s.play.adsr = flatAdsr();
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 80);
CHECK(approx(sourceFrameOf(out[51]), 51.0, 1e-3));
CHECK(approx(sourceFrameOf(out[52]), 52.0, 1e-3)); // weight 0 at the region edge
for (int n = 52; n < 60; ++n) {
// Normalized over crossfade - 1 (= 7), not crossfade: weight reaches exactly 1 at
// n == 59 (d == 7 == xf - 1), not merely approaching it.
const double w = static_cast<double>(n - 52) / 7.0;
const double want = static_cast<double>(n) * (1.0 - w) + static_cast<double>(n - 20) * w;
CHECK(approx(sourceFrameOf(out[static_cast<std::size_t>(n)]), want, 1e-3));
}
for (int n = 53; n < 60; ++n) {
CHECK(out[static_cast<std::size_t>(n)] < out[static_cast<std::size_t>(n - 1)]);
}
}
// What the crossfade actually buys, measured rather than asserted by adjective: normalizing
// over crossfade - 1 (loop_span.h) lands the weight at exactly 1 on the last rendered frame
// (end - 1) for every REAL crossfade length (xf >= 2), not merely approaching it — that frame
// is the incoming tap outright, which is exactly the value the wrap hands over. The step across
// the seam is therefore the material's own natural one-frame step (indexSample's slope is 1 raw
// frame per frame), constant for any xf >= 2 — not a residual that merely shrinks with a longer
// fade. The |out[60]-out[59]| metric is otherwise a trap: it conflates the natural step with any
// leftover discontinuity, and at xf == loop length the OLD 1/xf normalization happened to score
// 0 by this same metric — a coincidence of that one ratio, not a property of the fix. Comparing
// against the natural step rather than "small" or "zero" closes that hole.
static void testSeamStepMatchesTheNaturalStepForAnyCrossfade() {
auto seamStep = [](std::int64_t xf) {
return std::fabs(loopedFrameValue(xf, 60) - loopedFrameValue(xf, 59));
};
// No crossfade: the seam is the whole loop length less one frame — the wart the fade fixes.
CHECK(approx(seamStep(0), 19.0, 1e-3));
// xf == 1 has no fractional region to blend — its one frame sits exactly at d == 0, caught
// by crossfadeWeight's own d <= 0 floor before the multiply/ceiling ever runs — so it is
// still the hard seam, not a one-frame fade.
CHECK(approx(seamStep(1), 19.0, 1e-3));
// Any REAL crossfade length: the step is exactly the natural one-frame step, not merely
// small — and constant regardless of the fade length, unlike the old formula's proportional
// shrink.
for (std::int64_t xf : {std::int64_t{4}, std::int64_t{8}, std::int64_t{16},
std::int64_t{20}}) {
CHECK(approx(seamStep(xf), 1.0, 1e-3));
}
}
static void testCrossfadeLengthFollowsItsParameter() {
// A longer fade starts earlier and nowhere else: the region begin is end - crossfade, so
// doubling the parameter doubles the number of blended frames.
auto firstFadedFrame = [](std::int64_t xf) {
SampleData s = indexSample(100);
s.loop.hasLoop = true;
s.loop.start = 40;
s.loop.end = 60;
s.loopCrossfadeFrames = xf;
s.play.adsr = flatAdsr();
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 70);
for (int n = 40; n < 60; ++n) {
const double got = sourceFrameOf(out[static_cast<std::size_t>(n)]);
if (!approx(got, static_cast<double>(n), 1e-3)) return n;
}
return 60;
};
CHECK(firstFadedFrame(0) == 60); // never diverges from the raw read
CHECK(firstFadedFrame(4) == 57); // region [56,60); frame 56 carries weight 0
CHECK(firstFadedFrame(8) == 53); // region [52,60)
CHECK(firstFadedFrame(16) == 45); // region [44,60)
}
// The fade cannot read before frame 0, so a loop starting at 0 gets none — silently clamped
// rather than reading out of bounds or refusing the loop outright.
static void testCrossfadeIsSuppressedForALoopAtFrameZero() {
SampleData s = indexSample(100);
s.loop.hasLoop = true;
s.loop.start = 0;
s.loop.end = 20;
s.loopCrossfadeFrames = 16;
s.play.adsr = flatAdsr();
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 60);
CHECK(eng.activeVoiceCount() == 1);
for (int n = 0; n < 20; ++n) {
CHECK(approx(sourceFrameOf(out[static_cast<std::size_t>(n)]),
static_cast<double>(n), 1e-3));
}
}
static void testNoteOffDuringLoopSustainRunsTheReleaseAndFreesTheVoice() {
// The loop is the SUSTAIN: held, the voice never ends; released, it must leave the
// sustain level down the release ramp and free itself — not keep cycling forever.
SampleData s = dcSample(60, 60); // flat 1.0 so output IS the envelope
s.loop.hasLoop = true;
s.loop.start = 20;
s.loop.end = 40;
s.loopCrossfadeFrames = 4;
AdsrParams a = flatAdsr();
a.releaseFrames = 32;
s.play.adsr = a;
VoiceEngine eng(1, s);
eng.noteOn(60, 127);
std::vector<AudioSample> held;
eng.render(held, 500); // far past the sample end
CHECK(eng.activeVoiceCount() == 1);
CHECK(approx(held.back(), 1.0, 1e-4)); // still at sustain, still looping
eng.noteOff(60);
std::vector<AudioSample> tail;
eng.render(tail, 16);
// Mid-release: audibly decaying, not yet done.
CHECK(tail.back() < 0.75 && tail.back() > 0.0);
CHECK(eng.activeVoiceCount() == 1);
std::vector<AudioSample> rest;
eng.render(rest, 64);
CHECK(eng.activeVoiceCount() == 0);
CHECK(approx(rest.back(), 0.0, 1e-6));
}
// Preserve's contract is LOOP THE SOURCE, SHIFT THE OUTPUT: the loop points name source
// frames, so a transposed note loops the same source span and keeps sounding at level. If the
// span were treated as an output-domain fact, an up-shifted voice would outrun it, freeze its
// shifter tail and decay. Run with and without a crossfade, since the fade is applied to the
// SOURCE feed ahead of the shifter and the ring prime walks the same blend.
static void testPreserveLoopsTheSourceSpanAtEveryTransposition() {
for (std::int64_t xf : {std::int64_t{0}, std::int64_t{16}}) {
for (int note : {48, 60, 72}) {
SampleData s;
s.frames.resize(200, 0.0f);
for (int i = 60; i < 120; ++i) s.frames[i] = 0.5f; // the loop body + its run-in
s.rootNote = 60;
s.sampleRate = 48000;
s.loop.hasLoop = true;
s.loop.start = 80;
s.loop.end = 120;
s.loopCrossfadeFrames = xf;
s.play.adsr = flatAdsr();
s.play.pitchEngine = PitchEngine::Preserve;
VoiceEngine eng(1, s);
eng.noteOn(note, 127);
std::vector<AudioSample> out;
eng.render(out, 4000); // 20x the sample length
// The source span is finite; only the loop can keep a voice alive this long, and
// it does so at every transposition because the span is a source-frame fact.
CHECK(eng.activeVoiceCount() == 1);
// And it is still delivering the loop body, not a decaying frozen tail. The body
// and its run-in are one constant, so the shifter's splices reproduce it whatever
// the shift ratio and whatever the fade blends.
double sum = 0.0;
for (std::size_t i = out.size() - 200; i < out.size(); ++i) sum += out[i];
CHECK(approx(sum / 200.0, 0.5, 0.05));
}
}
}
// ---------------------------------------------------------------------------
// velocity -> volume.
// ---------------------------------------------------------------------------
// S-VIEW-9 BEHAVIOR CHANGE (R10-F1 Option A): the DEFAULT velocity curve is now flat
// y=1, so EVERY velocity plays at unity — NOT the old linear velocity/127. singleSampleChromatic
// builds a zone with the flat default, so the DC-1 sample renders 1.0 at any velocity.
static void testVelocityDefaultCurveIsFlatUnity() {
SampleData km = (dcSample(100, 60)); // DC 1.0, flat default curve
for (int vel : {1, 64, 100, 127}) {
VoiceEngine eng(1, km);
eng.noteOn(60, vel);
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(approx(out[0], 1.0, 1e-4)); // flat y=1: any velocity -> unity gain
}
}
// A LINEAR curve on the zone reproduces the pre-r10 velocity/127 ramp exactly — proving the curve
// (not a hardcoded map) drives the gain, and that eval is applied at note-on.
static void testVelocityLinearCurveReproducesRamp() {
SampleData km = (dcSample(100, 60)); // DC 1.0
km.velocityCurve = VelocityCurve::linear();
{
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out; eng.render(out, 1);
CHECK(approx(out[0], 1.0, 1e-4));
}
{
VoiceEngine eng(1, km);
eng.noteOn(60, 64);
std::vector<AudioSample> out; eng.render(out, 1);
CHECK(approx(out[0], 64.0 / 127.0, 1e-4));
}
{
VoiceEngine eng(1, km);
eng.noteOn(60, 1);
std::vector<AudioSample> out; eng.render(out, 1);
CHECK(approx(out[0], 1.0 / 127.0, 1e-4));
}
}
// A shaped curve (a single interior knot) drives the gain through eval — a mid velocity reads the
// curve's shaped value, not the linear one. Proves the whole curve, not just the endpoints, applies.
static void testVelocityShapedCurveDrivesGain() {
SampleData km = (dcSample(100, 60)); // DC 1.0
VelocityCurve curve = VelocityCurve::linear();
curve.addPoint(64.0, 0.9); // pull the mid-velocity response UP to 0.9
km.velocityCurve = curve;
VoiceEngine eng(1, km);
eng.noteOn(60, 64);
std::vector<AudioSample> out; eng.render(out, 1);
// At exactly velocity 64 the curve passes through the knot -> gain 0.9 (well above the linear
// 64/127 ~= 0.504), so the rendered DC value is the shaped 0.9.
CHECK(approx(out[0], 0.9, 1e-4));
}
// Two voices summed: polyphony mixes additively.
static void testPolyphonyMixesAdditively() {
SampleData km = (dcSample(100, 60)); // DC 1.0
VoiceEngine eng(4, km);
eng.noteOn(60, 127); // gain 1.0
eng.noteOn(60, 127); // gain 1.0 (second voice, same note)
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(approx(out[0], 2.0, 1e-4)); // both voices sum
}
// ---------------------------------------------------------------------------
// 7. Stereo channel dimension (S7).
// ---------------------------------------------------------------------------
// A distinct-per-channel stereo DC sample: L = `l`, R = `r` everywhere. A stereo render
// must keep them distinct; a mono render (channel 0 only) sees L.
static SampleData stereoDcSample(std::size_t frames, float l, float r, int rootNote = 60) {
SampleData s;
s.frames.assign(frames, l);
s.framesR.assign(frames, r);
s.rootNote = rootNote;
return s;
}
static void testChannelCount() {
// Mono: framesR empty -> 1 channel. Stereo: matching-length framesR -> 2.
CHECK(dcSample(10, 60).channelCount() == 1);
CHECK(stereoDcSample(10, 1.0f, -1.0f).channelCount() == 2);
// A mismatched framesR length is treated as mono (a bad pair never half-plays).
SampleData bad = dcSample(10, 60);
bad.framesR.assign(5, 0.5f); // wrong length
CHECK(bad.channelCount() == 1);
}
static void testStereoRenderKeepsChannelsDistinct() {
// A stereo sample (L=1.0, R=-1.0) rendered stereo must emit L and R distinctly, each
// scaled by velocity (full here). If the engine copied L to both channels the R check fails.
SampleData km = (stereoDcSample(100, 1.0f, -1.0f, 60));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> left(8, 0.f), right(8, 0.f);
eng.render(left.data(), right.data(), 8);
for (std::size_t i = 0; i < 8; ++i) {
CHECK(approx(left[i], 1.0, 1e-4)); // channel 0
CHECK(approx(right[i], -1.0, 1e-4)); // channel 1 — distinct, NOT a copy of L
}
}
static void testMonoSamplePlaysDualMonoInStereo() {
// A MONO sample rendered through the stereo path plays dual-mono: both channels equal
// (centered), not silent on the right. The cross-mode "mono source in stereo mode" case.
SampleData km = (dcSample(100, 60)); // mono, DC 1.0
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> left(8, 0.f), right(8, 0.f);
eng.render(left.data(), right.data(), 8);
for (std::size_t i = 0; i < 8; ++i) {
CHECK(approx(left[i], 1.0, 1e-4));
CHECK(approx(right[i], 1.0, 1e-4)); // R == L (dual-mono), not 0
}
}
static void testDualMonoStereoSampleRendersCentered() {
// GA Bug 1 (pure-layer proof): a STEREO sample whose two channels are IDENTICAL (a
// dual-mono capture) must render EXACTLY equal L and R — bitwise, every frame — under
// BOTH pitch engines. Any asymmetry here (a silent L, a channel offset, divergent
// shifter state) would pan the output; hard-panned output from a dual-mono capture
// therefore cannot originate in the engine.
auto renderBoth = [](PitchEngine engine, int note) {
SampleData s = sineSample(600, 12.0, 60);
s.framesR = s.frames; // dual-mono: identical channels
s.play.pitchEngine = engine;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, /*preserveWindowFrames=*/128);
eng.noteOn(note, 127);
std::vector<AudioSample> left(256, 0.f), right(256, 0.f);
eng.render(left.data(), right.data(), 256);
bool sound = false, equal = true;
for (std::size_t i = 0; i < left.size(); ++i) {
if (left[i] != 0.0f) sound = true;
if (left[i] != right[i]) equal = false; // EXACT: dual-mono must be centered
}
CHECK(sound); // the render actually produced signal (a 0==0 pass would be vacuous)
CHECK(equal);
};
renderBoth(PitchEngine::Varispeed, 60);
renderBoth(PitchEngine::Varispeed, 67); // off-root: repitch rides both channels equally
renderBoth(PitchEngine::Preserve, 60); // both shifters run (no unity demotion in MIDI)
renderBoth(PitchEngine::Preserve, 67); // off-root Preserve: per-channel shift, same state
}
static void testMonoRenderUnchangedByStereoData() {
// Regression: the mono render path (renderFrame) reads channel 0 ONLY and is byte-identical
// whether or not a second channel is present. A stereo sample rendered mono == its L channel.
SampleData kmS = (stereoDcSample(100, 0.75f, -0.25f, 60));
VoiceEngine engS(1, kmS);
engS.noteOn(60, 127);
std::vector<AudioSample> mono;
engS.render(mono, 8); // the mono overload
for (std::size_t i = 0; i < 8; ++i) CHECK(approx(mono[i], 0.75, 1e-4)); // == L, ignores R
}
static void testStereoRenderAdvancesLikeMonoRepitch() {
// The stereo path must advance the read head by the SAME per-frame ratio as the mono path,
// so repitch is identical. Play a stereo sine (both channels the same signal) an octave up
// and confirm the observed period halves — the mono repitch assertion, on the stereo path.
const std::size_t frames = 8000;
const double cycles = 20.0;
const double nativePeriod = static_cast<double>(frames) / cycles; // 400
SampleData s;
s.frames.resize(frames);
s.framesR.resize(frames);
for (std::size_t i = 0; i < frames; ++i) {
const float v = static_cast<float>(std::sin(2.0 * kPi * cycles *
static_cast<double>(i) / static_cast<double>(frames)));
s.frames[i] = v;
s.framesR[i] = v;
}
s.rootNote = 60;
SampleData km = (std::move(s));
VoiceEngine eng(4, km);
eng.noteOn(72, 127); // +1 octave
std::vector<AudioSample> left(frames / 2, 0.f), right(frames / 2, 0.f);
eng.render(left.data(), right.data(), frames / 2);
CHECK(approx(observedPeriodFrames(left), nativePeriod / 2.0, 2.0));
CHECK(approx(observedPeriodFrames(right), nativePeriod / 2.0, 2.0)); // R repitches identically
}
static void testStereoRenderSumsVoicesPerChannel() {
// Two voices on a stereo sample sum PER CHANNEL (additive polyphony holds in stereo).
SampleData km = (stereoDcSample(100, 0.5f, -0.5f, 60));
VoiceEngine eng(4, km);
eng.noteOn(60, 127);
eng.noteOn(60, 127); // second voice, same note
std::vector<AudioSample> left(1, 0.f), right(1, 0.f);
eng.render(left.data(), right.data(), 1);
CHECK(approx(left[0], 1.0, 1e-4)); // 0.5 + 0.5
CHECK(approx(right[0], -1.0, 1e-4)); // -0.5 + -0.5
}
static void testStereoRenderNullBufferIsNoOp() {
SampleData km = (stereoDcSample(100, 1.0f, -1.0f, 60));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> buf(4, 0.f);
eng.render(nullptr, buf.data(), 4); // null left -> no-op, no crash
eng.render(buf.data(), nullptr, 4); // null right -> no-op
for (float v : buf) CHECK(approx(v, 0.0, 1e-9)); // untouched
}
static void testStereoStartFrameLoopShareOneReadHead() {
// S7 x S11 compose: a STEREO sample with a startFrame AND a sustain loop must read BOTH
// channels from the SAME single read head — one offset, one loop wrap, applied to L and R
// identically (only the sampled value differs). A per-frame L/R ramp that is a fixed offset
// apart (R = L + 0.5) pins the read position on both channels: if the stereo path ever gave
// L and R independent heads, the constant L->R offset would break at the start jump or the
// loop seam.
SampleData s;
s.frames.resize(40);
s.framesR.resize(40);
for (int i = 0; i < 40; ++i) {
s.frames[i] = static_cast<float>(i) * 0.01f; // L: 0.00 .. 0.39
s.framesR[i] = static_cast<float>(i) * 0.01f + 0.5f; // R: L + 0.5, everywhere
}
s.rootNote = 60;
s.startFrame = 10; // begin BOTH channels at frame 10
s.loop.hasLoop = true;
s.loop.start = 20;
s.loop.end = 30; // loop [20,30): frames 20..29
CHECK(s.channelCount() == 2);
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // unity ratio, full velocity, flat gain
std::vector<AudioSample> left(200, 0.f), right(200, 0.f);
eng.render(left.data(), right.data(), 200);
// First frame: both channels start at frame 10 (L=0.10, R=0.60) — the shared start offset.
CHECK(approx(left[0], 0.10, 1e-4));
CHECK(approx(right[0], 0.60, 1e-4));
// The loop sustains the voice indefinitely.
CHECK(eng.activeVoiceCount() == 1);
// At every rendered frame R - L == 0.5 exactly: both channels read the SAME frame index
// (one read head) through the start jump and every loop wrap. A per-channel head drift would
// break this invariant at the seam.
for (std::size_t i = 0; i < left.size(); ++i) {
CHECK(approx(right[i] - left[i], 0.5, 1e-4));
}
// Once fully inside the loop (start=10 -> reaches loop.start=20 within a handful of unity-ratio
// frames), every L value sits in the loop band [0.20, 0.30): the shared head is sustaining the
// loop region on both channels, never running off the sample end.
for (std::size_t i = 15; i < left.size(); ++i) {
CHECK(left[i] >= 0.20 - 1e-4 && left[i] < 0.30 + 1e-4);
}
}
// ===========================================================================
// S15 — sampling modes (Gate AHDSR hold stage, Trigger %-length + fades, note-off immunity).
// ===========================================================================
// --- AHDSR hold stage vs a known signal. ---
static void testAhdsrHoldStageShape() {
// Gate grows a HOLD stage between Attack and Decay: attack 0->1 (5f), HOLD at 1.0 (8f),
// decay 1->0.5 (5f), sustain 0.5. Assert the hold plateau is exactly 1.0 for holdFrames.
AdsrParams p;
p.attackFrames = 5;
p.holdFrames = 8;
p.decayFrames = 5;
p.sustainLevel = 0.5;
p.releaseFrames = 5;
AdsrEnvelope env;
env.configure(p);
env.noteOn();
for (int i = 0; i < 5; ++i) env.tick(); // consume Attack (ends at 1.0)
// The next holdFrames ticks must all be exactly 1.0 (the plateau), stage == Hold.
for (int i = 0; i < 8; ++i) {
CHECK(env.stage() == AdsrEnvelope::Stage::Hold);
CHECK(approx(env.tick(), 1.0, 1e-9));
}
// Then Decay begins, falling from 1.0 toward sustain 0.5.
CHECK(env.stage() == AdsrEnvelope::Stage::Decay);
double v = env.tick();
CHECK(v <= 1.0 + 1e-9 && v >= 0.5 - 1e-9);
}
// --- hold == 0 is byte-identical to the pre-S15 ADSR (back-compat regression). ---
static void testAhdsrHoldZeroEqualsAdsr() {
// The load-bearing back-compat guarantee: hold=0 reproduces the classic ADSR frame-for-frame.
// Assert against a HAND-COMPUTED expected sequence (not another envelope — that would be
// tautological). attack 4, hold 0, decay 4, sustain 0.5. Expected per-tick output:
// Attack: 0/4, 1/4, 2/4, 3/4 (ticks 0..3, level rising 0 -> 0.75)
// Decay: 1.0, then 1.0+(0.5-1)*t for t=1/4..3/4 (ticks 4..7: 1.0, 0.875, 0.75, 0.625)
// Sustain: 0.5 forever (tick 8+)
AdsrParams p;
p.attackFrames = 4;
p.holdFrames = 0; // the degenerate — must NOT insert an extra unity frame
p.decayFrames = 4;
p.sustainLevel = 0.5;
p.releaseFrames = 4;
AdsrEnvelope env;
env.configure(p);
env.noteOn();
const double expected[] = {0.0, 0.25, 0.5, 0.75, // attack
1.0, 0.875, 0.75, 0.625, // decay (first sample 1.0 at t=0)
0.5, 0.5, 0.5}; // sustain
for (double e : expected) CHECK(approx(env.tick(), e, 1e-9));
CHECK(env.stage() == AdsrEnvelope::Stage::Sustain); // reached sustain at the SAME tick count
}
// A trigger-mode DC sample (all 1.0) so a rendered voice's output tracks the trigger envelope
// * velocity directly. `attack`/`decay` are the AHD's ramp lengths in frames, with Hold taking
// the whole remainder — the shape that replaced the retired fade pair. Varispeed so no shift
// colours the amp.
static SampleData triggerSample(std::size_t frames, double lengthFraction,
std::int64_t attack, std::int64_t decay,
std::int64_t startFrame = 0) {
SampleData s = dcSample(frames, 60);
s.startFrame = startFrame;
s.play.playMode = PlayMode::Trigger;
s.play.pitchEngine = PitchEngine::Varispeed; // isolate amp shape from pitch
s.play.trigger.lengthFraction = lengthFraction;
s.play.trigAhd.attackFrames = attack;
s.play.trigAhd.decayFrames = decay;
s.play.trigAhd.holdFraction = 1.0;
return s;
}
// --- Trigger %-length frame math: plays exactly round(frac*(frames-start)) frames then frees. ---
static void testTriggerLengthFractionFrames() {
// 200-frame sample, start 0, 50% length -> plays 100 frames then the voice frees.
SampleData km = (triggerSample(200, 0.5, 0, 0));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // unity ratio
std::vector<AudioSample> out;
eng.render(out, 200);
// First 100 frames sound (amp>0 for a no-fade trigger = 1.0), then silence + voice freed.
for (std::size_t i = 0; i < 100; ++i) CHECK(out[i] > 0.5f);
for (std::size_t i = 100; i < 200; ++i) CHECK(approx(out[i], 0.0, 1e-6));
CHECK(eng.activeVoiceCount() == 0); // ran off playEnd
}
// --- Trigger start point: %-length measured from the start offset. ---
static void testTriggerLengthWithStart() {
// 200 frames, start 40, 50% -> span 160, play 80 frames (frames 40..119), then free.
SampleData km = (triggerSample(200, 0.5, 0, 0, /*start=*/40));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 200);
for (std::size_t i = 0; i < 80; ++i) CHECK(out[i] > 0.5f);
for (std::size_t i = 80; i < 200; ++i) CHECK(approx(out[i], 0.0, 1e-6));
CHECK(eng.activeVoiceCount() == 0);
}
// --- Trigger fade-in / fade-out ramp shape (equal-power default). ---
// 100 frames, 100% length, attack 20 / decay 20, holdFraction 1.0 — triggerSample() sets no
// curve exponent, so both stages default to util::kCurveNeutral (1.0): the ramps are LINEAR,
// not the retired fade pair's equal-power sin/cos. Asserted against the closed form rather
// than monotonicity alone — a monotonicity-only check is blind to exactly this shape change.
static void testTriggerAhdFadeShape() {
SampleData km = (triggerSample(100, 1.0, 20, 20));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 120);
for (std::size_t i = 0; i < 20; ++i) {
CHECK(approx(out[i], static_cast<double>(i) / 20.0, 1e-3));
}
// Hold plateau at unity.
for (std::size_t i = 20; i < 80; ++i) CHECK(approx(out[i], 1.0, 1e-3));
for (std::size_t i = 80; i < 100; ++i) {
CHECK(approx(out[i], 1.0 - static_cast<double>(i - 80) / 20.0, 1e-3));
}
// Past playEnd = silence.
for (std::size_t i = 100; i < 120; ++i) CHECK(approx(out[i], 0.0, 1e-6));
}
// --- Trigger edge cases: %=0 (immediate free) and fades overlapping (clamped). ---
static void testTriggerEdgeCases() {
// %=0: zero play length -> voice frees at once, no sound.
{
SampleData km = (triggerSample(100, 0.0, 5, 5));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 50);
for (float v : out) CHECK(approx(v, 0.0, 1e-6));
CHECK(eng.activeVoiceCount() == 0);
}
// AHD attack + decay beyond the play length are fitted by fitAhd, not overflowed (no crash, no negative gain, amp in [0,1]).
{
// 40 frames, 100% -> playLen 40; fadeIn 30 + fadeOut 30 = 60 > 40 -> clamped.
SampleData km = (triggerSample(40, 1.0, 30, 30));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 50);
for (std::size_t i = 0; i < 40; ++i) CHECK(out[i] >= -1e-4 && out[i] <= 1.0 + 1e-4);
CHECK(eng.activeVoiceCount() == 0);
}
// %=100 plays the full post-start span.
{
SampleData km = (triggerSample(60, 1.0, 0, 0));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 80);
for (std::size_t i = 0; i < 60; ++i) CHECK(out[i] > 0.5f);
for (std::size_t i = 60; i < 80; ++i) CHECK(approx(out[i], 0.0, 1e-6));
}
}
// --- Trigger ignores note-off (S15): the one-shot plays through regardless. ---
static void testTriggerIgnoresNoteOff() {
SampleData km = (triggerSample(200, 0.5, 0, 0));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 10);
eng.noteOff(60); // must be a NO-OP in Trigger
CHECK(eng.activeVoiceCount() == 1); // still sounding after note-off
eng.render(out, 200);
// It still plays its full 100-frame length (frames 10..99 remain > 0 after the note-off).
for (std::size_t i = 10; i < 100; ++i) CHECK(out[i] > 0.5f);
for (std::size_t i = 100; i < 210; ++i) CHECK(approx(out[i], 0.0, 1e-6));
CHECK(eng.activeVoiceCount() == 0); // frees on its own playEnd, not on note-off
}
// ===========================================================================
// S16 — pitch engine (Preserve duration invariance) + pitch envelope (off = identical).
// ===========================================================================
// Render one note to completion (or `maxFrames`) and return the frame count at which the voice
// went idle (the audible LENGTH). A Gate note with a short release + a finite sample runs off.
static std::size_t soundingLength(VoiceEngine& eng, std::size_t maxFrames) {
std::vector<AudioSample> out;
std::size_t len = 0;
for (std::size_t f = 0; f < maxFrames; ++f) {
eng.render(out, 1);
if (eng.activeVoiceCount() > 0) len = f + 1;
else break;
}
return len;
}
// A Preserve-engine one-shot Trigger sample: under Preserve, the %-length wall-clock is stable
// under transpose (the S15xS16 contract). Trigger + Preserve isolates the length measurement from
// Gate's release tail.
static SampleData preserveTriggerSample(std::size_t frames, double lengthFraction) {
SampleData s = dcSample(frames, 60);
s.play.playMode = PlayMode::Trigger;
s.play.pitchEngine = PitchEngine::Preserve;
s.play.trigger.lengthFraction = lengthFraction;
return s;
}
// --- Preserve duration invariance: same note length across +/-12 semitones. ---
static void testPreserveDurationInvariance() {
// A Preserve Trigger at 100% length of a 1000-frame sample plays ~1000 output frames
// regardless of transpose (duration held). Under Varispeed an octave up would halve it.
const std::size_t frames = 1000;
const std::size_t window = 512; // pre-size the shifters
auto lengthAt = [&](int note) -> std::size_t {
SampleData km = (preserveTriggerSample(frames, 1.0));
VoiceEngine eng(1, km, /*preserveCap=*/0, /*window=*/static_cast<std::int64_t>(window));
eng.noteOn(note, 127);
return soundingLength(eng, 4000);
};
const std::size_t atRoot = lengthAt(60);
const std::size_t atUp = lengthAt(72); // +12
const std::size_t atDown = lengthAt(48); // -12
// All three within a small tolerance of the source length (Preserve holds duration). The
// tolerance covers the shifter's fill/latency edge and the terminal ring-out Preserve ends
// on (voice.h's seedTerminalDeclick — bounded by the declick floor at ~185 frames), not a
// duration scaling, which would be 2x.
const std::size_t kTail = 200;
CHECK(atRoot >= frames - 20 && atRoot <= frames + kTail);
CHECK(atUp >= frames - 20 && atUp <= frames + kTail);
CHECK(atDown >= frames - 20 && atDown <= frames + kTail);
// The decisive assertion: the up/down lengths track the root length (NOT halved/doubled).
CHECK(atUp > frames / 2 + 200); // an octave up did NOT halve the duration (Varispeed would)
CHECK(atDown < frames * 2 - 200); // an octave down did NOT double it
}
// --- Varispeed still couples duration (the contrast to Preserve — regression on the old default). ---
static void testVarispeedStillCouplesDuration() {
// A Varispeed Trigger octave up runs off in ~half the frames (pitch & duration coupled).
auto lengthAt = [&](int note) -> std::size_t {
SampleData s = dcSample(1000, 60);
s.play.playMode = PlayMode::Trigger;
s.play.pitchEngine = PitchEngine::Varispeed;
s.play.trigger.lengthFraction = 1.0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(note, 127);
return soundingLength(eng, 4000);
};
const std::size_t atRoot = lengthAt(60);
const std::size_t atUp = lengthAt(72);
CHECK(approx(static_cast<double>(atUp), static_cast<double>(atRoot) / 2.0, 30.0));
}
// --- Pitch envelope OFF == bit-identical to the un-modulated engine (regression). ---
static void testPitchEnvOffBitIdentical() {
// Two Varispeed voices, one with a disabled pitch env, one with no pitch env at all. Their
// rendered output must be BIT-IDENTICAL (pitch-env-off applies zero modulation — the S16
// "identical to pre-S16" guarantee). Uses a sine so any pitch drift would show as phase drift.
const std::size_t n = 4000;
auto renderOne = [&](bool withDisabledEnv) -> std::vector<AudioSample> {
SampleData s = sineSample(n, 20.0, 60);
s.play.pitchEngine = PitchEngine::Varispeed;
if (withDisabledEnv) {
s.play.pitchEnv.enabled = false; // explicitly disabled (offset always 0)
s.play.pitchEnv.peakSemitones = 12.0; // a depth that WOULD matter if enabled
s.play.pitchEnv.shape.attackFrames = 0;
s.play.pitchEnv.shape.decayFrames = 500;
}
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(67, 127); // a transposed note so ratio != 1 (exercises the ratio path)
std::vector<AudioSample> out;
eng.render(out, n);
return out;
};
const std::vector<AudioSample> a = renderOne(false);
const std::vector<AudioSample> b = renderOne(true);
CHECK(a.size() == b.size());
bool identical = a.size() == b.size();
for (std::size_t i = 0; i < a.size() && identical; ++i) {
if (a[i] != b[i]) identical = false;
}
CHECK(identical); // disabled pitch env produces the EXACT same samples (no modulation)
}
// --- Pitch envelope ON biases pitch (Varispeed): a positive-peak zero-attack env starts sharp. ---
static void testPitchEnvOnBendsVarispeed() {
// Zero attack + positive peak = "start high, drop to base": the note begins transposed UP and
// settles. Observe the read advancing FASTER at the start (period shorter early) than late.
const std::size_t n = 8000;
SampleData s = sineSample(n, 40.0, 60);
s.play.pitchEngine = PitchEngine::Varispeed;
s.play.pitchEnv.enabled = true;
s.play.pitchEnv.shape.attackFrames = 0; // start at the peak
s.play.pitchEnv.shape.decayFrames = 3000; // glide to base over 3000 frames
s.play.pitchEnv.peakSemitones = 12.0; // +1 octave at t=0
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127); // at root -> base ratio 1.0; the env supplies the bend
std::vector<AudioSample> out;
eng.render(out, 4000);
// Early period (heavily transposed up) should be shorter than the late period (settled).
std::vector<AudioSample> early(out.begin(), out.begin() + 800);
std::vector<AudioSample> late(out.begin() + 3200, out.begin() + 4000);
const double pe = observedPeriodFrames(early);
const double pl = observedPeriodFrames(late);
CHECK(pe > 0.0 && pl > 0.0);
CHECK(pe < pl); // pitch dropped over time (period lengthened) -> the AD env bent the pitch
}
// --- Compose: engine x mode x stereo x loop (a Preserve Gate loop in stereo sounds + sustains). ---
static void testPreserveGateStereoLoopComposes() {
// A STEREO sample, GATE mode, PRESERVE engine, with a sustain loop. It must sound on BOTH
// channels and sustain (the loop keeps the voice alive) — S7 x S15 x S16 all composing.
SampleData s;
const std::size_t frames = 400;
s.frames.resize(frames);
s.framesR.resize(frames);
for (std::size_t i = 0; i < frames; ++i) {
const float v = static_cast<float>(std::sin(2.0 * kPi * 8.0 *
static_cast<double>(i) / static_cast<double>(frames)));
s.frames[i] = v;
s.framesR[i] = v * 0.5f; // R is a distinct (half-amplitude) channel
}
s.rootNote = 60;
s.loop.hasLoop = true;
s.loop.start = 100;
s.loop.end = 300;
s.play.playMode = PlayMode::Gate;
s.play.pitchEngine = PitchEngine::Preserve;
CHECK(s.channelCount() == 2);
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 512);
eng.noteOn(67, 127); // transposed up a fifth under Preserve (duration held)
std::vector<AudioSample> left(2000, 0.f), right(2000, 0.f);
eng.render(left.data(), right.data(), 2000);
// The loop sustains the voice well past the sample length (400 frames) -> still active.
CHECK(eng.activeVoiceCount() == 1);
// Both channels carry signal (some frame has non-trivial magnitude on each).
double maxL = 0.0, maxR = 0.0;
for (std::size_t i = 600; i < 2000; ++i) {
if (std::fabs(left[i]) > maxL) maxL = std::fabs(left[i]);
if (std::fabs(right[i]) > maxR) maxR = std::fabs(right[i]);
}
CHECK(maxL > 0.05);
CHECK(maxR > 0.02); // R present (half amplitude), distinct from L -> stereo preserved
// Loop-never-freezes regression: the Preserve voice must NOT spuriously freeze when the
// read tap hits the sample end and the loop wraps it back. A spuriously frozen voice
// stops writing to the ring and the looped tail would go silent past the sample end.
// Check a block far past the sample end (sample = 400 frames; window = 512; well past
// any single-pass tail region) to catch any wrap-before-exhaustion ordering error.
double maxLFar = 0.0;
for (std::size_t i = 1800; i < 2000; ++i) {
if (std::fabs(left[i]) > maxLFar) maxLFar = std::fabs(left[i]);
}
CHECK(maxLFar > 0.05); // still alive at frame 1800 (4.5× the 400-frame sample length)
}
// --- Preserve voice cap: a Preserve note-on past the cap is dropped; Varispeed unaffected. ---
// EVERY engine Preserve voice (root included) runs the shifter and counts toward the cap —
// the FA1 unity demotion is gone (it was scoped to the retired PreviewCard).
static void testPreserveVoiceCap() {
SampleData s = dcSample(2000, 60);
s.play.pitchEngine = PitchEngine::Preserve; // held (Gate, no loop -> runs long enough)
SampleData km = (std::move(s));
// 8 voices total, Preserve cap of 2.
VoiceEngine eng(8, km, /*preserveCap=*/2, /*window=*/256);
CHECK(eng.noteOn(62, 127) != VoiceEngine::kNoVoice); // 1st Preserve voice
CHECK(eng.noteOn(64, 127) != VoiceEngine::kNoVoice); // 2nd Preserve voice (at the cap)
CHECK(eng.noteOn(65, 127) == VoiceEngine::kNoVoice); // 3rd DROPPED by the Preserve cap
CHECK(eng.activeVoiceCount() == 2);
}
// ---------------------------------------------------------------------------
// FA1 postscript — the Preserve unity-Varispeed bypass is REMOVED with the PreviewCard
// (preview is now a plain engine noteOn at the root). The engine keeps the shifter at
// EVERY Preserve note; GA2's primed ring speaks on frame 0 at every ratio, so onset is
// uniformly IMMEDIATE across the keyboard with no demotion path at all.
// ---------------------------------------------------------------------------
// The ENGINE'S root-note Preserve voice keeps the OLA path — and since the GA2 prime fix the
// primed shifter speaks on frame 0 at EVERY ratio (the ring holds the first window of real
// source, not warm-up zeros). Uniform onset across the keyboard now means uniformly IMMEDIATE:
// the root and a transposed neighbor both open at full level on the very first frames.
static void testPreserveUnityEngineVoiceSpeaksImmediately() {
auto earlyAndLate = [](int note, double& early, double& late) {
SampleData s = dcSample(4000, 60);
s.play.pitchEngine = PitchEngine::Preserve;
s.play.adsr = flatAdsr(); // isolate the shifter onset from the amp attack
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, /*window=*/512);
eng.noteOn(note, 127);
std::vector<AudioSample> out;
eng.render(out, 1500);
early = 1e9;
for (std::size_t i = 0; i < 8; ++i) {
early = (std::min)(early, static_cast<double>(std::fabs(out[i])));
}
late = 0.0;
for (std::size_t i = 600; i < 1500; ++i) {
late = (std::max)(late, static_cast<double>(std::fabs(out[i])));
}
};
double earlyRoot = 0.0, lateRoot = 0.0, earlyUp = 0.0, lateUp = 0.0;
earlyAndLate(60, earlyRoot, lateRoot); // at root: unity shift — NO demotion in the engine
earlyAndLate(62, earlyUp, lateUp); // +2 st: a real shift, same immediate onset
CHECK(earlyRoot > 0.9); // primed ring: full level from frame 0 (no fill silence)
CHECK(earlyUp > 0.9); // ...uniformly across the keyboard (the GA2 onset-gap fix)
CHECK(lateRoot > 0.9);
CHECK(lateUp > 0.9); // and no gaps later either (splices land in real history)
}
// A TRANSPOSED Preserve note keeps the genuine OLA path — and since the GA2 prime fix that
// path has NO onset cost: the ring is primed with the first window of real source, so a
// transposed voice opens at full level on frame 0 (the DAW "zero-sample gaps in the first few
// ms" regression) and NEVER dips while the source sustains (splices land in real history, not
// warm-up zeros).
static void testPreserveTransposedVoiceSpeaksImmediately() {
SampleData s = dcSample(4000, 60);
s.play.pitchEngine = PitchEngine::Preserve;
s.play.adsr = flatAdsr(); // isolate the shifter onset from the amp attack
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, /*window=*/512);
eng.noteOn(62, 127); // +2 semitones: a real shift, NOT demoted
std::vector<AudioSample> out;
eng.render(out, 1500);
// Full level from the very first frame (a DC source through complementary crossfades and
// aligned splices holds 1.0 throughout) — pre-fix the first ~window was fill silence.
double lo = 1e9;
for (std::size_t i = 0; i < 1500; ++i) {
lo = (std::min)(lo, static_cast<double>(std::fabs(out[i])));
}
CHECK(lo > 0.9);
}
// Phase S re-scope consequence: a ROOT-note engine Preserve voice keeps its shifter, so it
// COUNTS toward the Preserve cap like any other (pre-re-scope it was demoted and exempt).
static void testPreserveUnityVoiceCountsTowardCap() {
SampleData s = dcSample(2000, 60);
s.play.pitchEngine = PitchEngine::Preserve;
SampleData km = (std::move(s));
VoiceEngine eng(8, km, /*preserveCap=*/2, /*window=*/256);
CHECK(eng.noteOn(60, 127) != VoiceEngine::kNoVoice); // root: a genuine Preserve voice now
CHECK(eng.noteOn(62, 127) != VoiceEngine::kNoVoice); // 2nd (at the cap)
CHECK(eng.noteOn(64, 127) == VoiceEngine::kNoVoice); // 3rd DROPPED by the Preserve cap
CHECK(eng.activeVoiceCount() == 2);
}
// FA1 bug 3a regression, in the DAW's ACTUAL configuration: the velocity curve must drive the
// gain under the PRESERVE product-default engine with a CONFIGURED shifter window (every prior
// velocity test ran the bare Varispeed core). A linear y=x curve at velocity 1 must be
// near-silent — NOT max volume.
static void testVelocityCurveAppliesUnderPreserve() {
auto steadyLevelAt = [&](int vel) -> double {
SampleData s = dcSample(4000, 60);
s.play.pitchEngine = PitchEngine::Preserve;
SampleData km = (std::move(s));
km.velocityCurve = VelocityCurve::linear();
VoiceEngine eng(1, km, /*preserveCap=*/0, /*window=*/256);
eng.noteOn(62, vel); // transposed: the genuine shifter path (not the unity demotion)
std::vector<AudioSample> out;
eng.render(out, 1000);
return static_cast<double>(out[900]); // steady state: ring is fully DC by frame 256
};
CHECK(approx(steadyLevelAt(127), 1.0, 0.02));
CHECK(approx(steadyLevelAt(64), 64.0 / 127.0, 0.02));
CHECK(steadyLevelAt(1) < 0.02); // y=x at velocity 1: near-silent, the Daniel repro case
}
// --- Per-zone A/D/S/R actually reaches the voice envelope (S12). ---
//
// Every AHDSR field rides on SampleData.play.adsr (frames, resolved from the stored seconds at
// keymap build); the engine holds no instrument-wide ADSR. These two tests assert that path.
// The zone's attackFrames drives the envelope ramp. Strategy: 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; a voice that ignored the zone ADSR (instant) would already be
// 1.0 at frame 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
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
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. A voice ignoring the zone ADSR would read 1.0 here.
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;
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
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));
}
// ---------------------------------------------------------------------------
// Phase S — parameterized voice count, MONO mode (last-note held stack, Retrigger/Legato),
// and the isolated PREVIEW CARD.
// ---------------------------------------------------------------------------
// A DC sample at `level` with a flat (instant, fully-open) envelope — rendered output equals
// level * velocity gain, so WHICH sample is sounding is directly observable in the mix.
static SampleData dcLevelSample(std::size_t frames, float level, int rootNote) {
SampleData s;
s.frames.assign(frames, level);
s.rootNote = rootNote;
s.play.adsr = flatAdsr();
return s;
}
// The mono tests need to read WHICH NOTE holds the single voice off the rendered value, and
// a DC sample makes pitch inaudible. Velocity is the discriminator: a DC 1.0 capture with a
// curve pinned through two probe velocities renders 0.25 for a kVelLow strike and 0.75 for a
// kVelHigh one (the Hermite spline passes exactly through its control points). Each test
// then presses note 50 soft and note 70 hard, so the level names the sounding note.
static constexpr int kVelLow = 32;
static constexpr int kVelHigh = 96;
static SampleData twoLevelSample() {
SampleData km = dcLevelSample(200000, 1.0f, 60);
km.velocityCurve = VelocityCurve::fromPoints({{0.0, 0.0},
{static_cast<double>(kVelLow), 0.25},
{static_cast<double>(kVelHigh), 0.75},
{127.0, 1.0}},
instrument::engine::CurveDomain::Unipolar);
return km;
}
// The rendered value on the next frame — one-frame probe of "what is sounding right now".
static double probeFrame(VoiceEngine& eng) {
std::vector<AudioSample> out;
eng.render(out, 1);
return static_cast<double>(out[0]);
}
// MONO last-note priority: a new note TAKES the single voice; releasing the top note falls
// back to the most-recent still-held note; releasing the last note gates off. Also: mono uses
// ONE voice regardless of the pool size.
static void testMonoLastNotePriorityAndFallback() {
SampleData km = twoLevelSample();
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
CHECK(eng.noteOn(50, kVelLow) == 0); // zone A sounds
CHECK(approx(probeFrame(eng), 0.25, 1e-6));
CHECK(eng.noteOn(70, kVelHigh) == 0); // zone B TAKES the voice (last-note priority)
CHECK(eng.activeVoiceCount() == 1); // mono: one voice even with 4 in the pool
CHECK(approx(probeFrame(eng), 0.75, 1e-6));
eng.noteOff(70); // top released -> FALLBACK to still-held 50
CHECK(approx(probeFrame(eng), 0.25, 1e-6));
eng.noteOff(50); // last finger up -> gate off (release 0 = instant)
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
CHECK(eng.activeVoiceCount() == 0);
}
// Releasing a LOWER held note (not the sounding one) changes nothing audible; the released
// note also leaves the stack, so the final note-off truly empties it.
static void testMonoReleaseOfLowerHeldNoteIsInaudible() {
SampleData km = twoLevelSample();
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
eng.noteOn(50, kVelLow);
eng.noteOn(70, kVelHigh); // 70 sounds, 50 held beneath
eng.noteOff(50); // releasing the buried note: inaudible
CHECK(approx(probeFrame(eng), 0.75, 1e-6));
eng.noteOff(70); // 50 already left the stack -> silence, no fallback
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
}
// Re-pressing a HELD note moves it to the top of the stack (it sounds again), and the note
// beneath becomes the fallback.
static void testMonoRepressHeldNoteMovesToTop() {
SampleData km = twoLevelSample();
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
eng.noteOn(50, kVelLow);
eng.noteOn(70, kVelHigh);
CHECK(eng.noteOn(50, kVelLow) == 0); // re-press while held: back on top
CHECK(approx(probeFrame(eng), 0.25, 1e-6));
eng.noteOff(50); // falls back to 70 (now the most recent held)
CHECK(approx(probeFrame(eng), 0.75, 1e-6));
eng.noteOff(70);
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
}
// A RETRIGGER fallback re-strikes the fallen-back-to note at ITS ORIGINAL velocity (kept per
// held note on the stack), not the departing note's.
static void testMonoRetriggerFallbackUsesOriginalVelocity() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
SampleData km = (std::move(s));
km.velocityCurve = VelocityCurve::linear(); // gain = velocity/127
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
eng.noteOn(60, 32); // soft first note
CHECK(approx(probeFrame(eng), 32.0 / 127.0, 1e-4));
eng.noteOn(64, 127); // loud takeover
CHECK(approx(probeFrame(eng), 1.0, 1e-6));
eng.noteOff(64); // fallback re-strikes 60 at ITS velocity (32)
CHECK(approx(probeFrame(eng), 32.0 / 127.0, 1e-4));
}
// An OUT-OF-RANGE note in mono is a defined no-play: it consumes nothing, never joins the
// stack (so it can never take the voice back on a fallback), and its note-off is inert. The
// stack keys notes as uint8, so an unguarded 200 would alias onto 72 and corrupt it.
static void testMonoOutOfRangeNeverJoinsStack() {
SampleData km = twoLevelSample();
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
eng.noteOn(70, kVelHigh);
CHECK(eng.noteOn(200, 127) == VoiceEngine::kNoVoice); // past the MIDI range
CHECK(eng.activeVoiceCount() == 1);
CHECK(approx(probeFrame(eng), 0.75, 1e-6)); // 70 undisturbed
eng.noteOff(200); // inert
CHECK(approx(probeFrame(eng), 0.75, 1e-6));
eng.noteOff(70);
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
}
// RETRIGGER restarts the amplitude envelope on a mono takeover: mid-attack level drops back
// to the ramp's origin when the new note takes the voice.
static void testMonoRetriggerRestartsEnvelope() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
s.play.adsr.attackFrames = 100; // slow linear attack: level at frame i = i/100
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 50); // mid-attack: level ~0.49 at frame 49
CHECK(approx(out[49], 0.49, 1e-6));
eng.noteOn(62, 127); // takeover: envelope RESTARTS
CHECK(approx(probeFrame(eng), 0.0, 1e-6)); // back at the attack origin
}
// LEGATO keeps the envelope running through a same-sample takeover: pitch moves, NO re-attack.
static void testMonoLegatoContinuesEnvelope() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
s.play.adsr.attackFrames = 100;
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 50);
CHECK(approx(out[49], 0.49, 1e-6));
eng.noteOn(62, 127); // legato takeover: envelope KEEPS running
CHECK(approx(probeFrame(eng), 0.50, 1e-6)); // frame 50 of the SAME attack ramp
}
// LEGATO retunes without restarting the read head, and the velocity gain stays the FIRST
// note's (a legato phrase is one gesture, one strike). Observed on a ramp sample: values
// continue from the current read position at the NEW pitch ratio; a soft second strike does
// not duck the level.
static void testMonoLegatoRetunesWithoutReadRestart() {
SampleData s;
s.frames.resize(200000);
for (std::size_t i = 0; i < s.frames.size(); ++i) {
s.frames[i] = static_cast<float>(i); // ramp: output value == read position
}
s.rootNote = 60;
s.play.adsr = flatAdsr();
SampleData km = (std::move(s));
km.velocityCurve = VelocityCurve::linear();
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(60, 127); // unity: read advances 1/frame, full gain
std::vector<AudioSample> out;
eng.render(out, 10);
CHECK(approx(out[9], 9.0, 1e-4));
eng.noteOn(72, 1); // legato to +1 octave at a WHISPER velocity
CHECK(approx(probeFrame(eng), 10.0, 1e-3)); // read CONTINUES at 10 — no restart, gain kept
CHECK(approx(probeFrame(eng), 12.0, 1e-3)); // and now advances at ratio 2 (the new pitch)
}
// LEGATO takeover ALWAYS glides now: with one loaded capture there is no second PCM stream
// to cross into, so the read head never has to restart mid-phrase. (The retired
// cross-sample-restart branch was the multi-zone case.)
static void testMonoLegatoAlwaysGlidesWithinThePhrase() {
SampleData km = twoLevelSample();
km.play.adsr.attackFrames = 100; // a slow attack would expose any restart
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(50, kVelLow);
std::vector<AudioSample> out;
eng.render(out, 50); // mid-attack: level ~0.49 * the 0.25 vel gain
CHECK(approx(out[49], 0.49 * 0.25, 1e-6));
eng.noteOn(70, kVelHigh); // takeover: envelope KEEPS running, no re-attack
// Frame 50 of the SAME attack ramp, still at the FIRST strike's velocity gain (a legato
// phrase is one gesture, one strike) — NOT 0.0 (a restart) and NOT 0.75 (a re-strike).
CHECK(approx(probeFrame(eng), 0.50 * 0.25, 1e-6));
}
// LEGATO after the last note was RELEASED re-attacks: a releasing voice's note has left the
// stack, so the next press is a fresh phrase, not a takeover.
static void testMonoLegatoAfterReleaseReattacks() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
s.play.adsr.attackFrames = 100;
s.play.adsr.releaseFrames = 1000; // long release keeps the voice audibly ringing
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 150); // through the attack: at full level
eng.noteOff(60); // release begins (stack now empty)
out.clear();
eng.render(out, 10);
eng.noteOn(62, 127); // a NEW phrase: re-attacks even in Legato
CHECK(approx(probeFrame(eng), 0.0, 1e-6)); // fresh attack origin, not the ringing level
}
// MONO does not apply the S16 Preserve cap: a single voice runs at most one shifter — a
// Preserve->Preserve takeover must never be dropped by the cap.
static void testMonoIgnoresPreserveCap() {
SampleData s = dcSample(4000, 60);
s.play.pitchEngine = PitchEngine::Preserve;
SampleData km = (std::move(s));
VoiceEngine eng(4, km, /*preserveCap=*/1, /*window=*/256,
VoiceMode::Mono, MonoTrigger::Retrigger);
CHECK(eng.noteOn(62, 127) == 0); // 1st Preserve note: at the cap
CHECK(eng.noteOn(64, 127) == 0); // takeover NOT dropped (poly cap would drop it)
CHECK(eng.activeVoiceCount() == 1);
}
// A ramp sample (output value == read position) so a re-attack (read restarts at 0) is
// directly distinguishable from a legato retune (read continues) on the rendered value.
static SampleData rampSample(std::size_t frames, int rootNote) {
SampleData s;
s.frames.resize(frames);
for (std::size_t i = 0; i < frames; ++i) s.frames[i] = static_cast<float>(i);
s.rootNote = rootNote;
s.play.adsr = flatAdsr();
return s;
}
// --- velocity -> pitch ---------------------------------------------------------
//
// A ramp sample reads its own position, so the value on frame N IS the accumulated read rate:
// the transpose is directly observable rather than inferred from a spectrum.
static void testVelocityPitchIsExactlyOffByDefault() {
// The modulation VALUE at every velocity, not a rendered approximation of it: the default
// bipolar curve must yield the identity ratio exactly, so nothing detunes by a hair.
const PlayParams def;
for (int v = 0; v <= 127; ++v) {
CHECK(velocityPitchRatio(def.pitchVelocityCurve, v) == 1.0);
}
// And at the render: two strikes of very different velocity read the ramp identically.
SampleData s = rampSample(4096, 60);
Voice soft;
Voice hard;
soft.start(60, 1, s);
hard.start(60, 127, s);
for (int i = 0; i < 64; ++i) CHECK(soft.renderFrame() == hard.renderFrame());
}
static void testDrawnVelocityPitchCurveTransposesBothWays() {
using instrument::engine::CurveDomain;
SampleData s = rampSample(4096, 60);
const double full = std::pow(2.0, kVelocityPitchRangeSemitones / 12.0);
// A curve pinned at +1 across the domain: every velocity transposes UP by the full scale.
s.play.pitchVelocityCurve =
VelocityCurve::fromPoints({{0.0, 1.0}, {127.0, 1.0}}, CurveDomain::Bipolar);
Voice up;
up.start(60, 100, s);
CHECK(approx(static_cast<double>(up.renderFrame()), 0.0, 1e-9));
CHECK(approx(static_cast<double>(up.renderFrame()), full, 1e-4));
// Pinned at -1: DOWN by the same scale — the half of the domain the old unipolar curve
// could not express at all.
s.play.pitchVelocityCurve =
VelocityCurve::fromPoints({{0.0, -1.0}, {127.0, -1.0}}, CurveDomain::Bipolar);
Voice down;
down.start(60, 100, s);
down.renderFrame();
CHECK(approx(static_cast<double>(down.renderFrame()), 1.0 / full, 1e-4));
// And it follows the curve: a rising ramp gives a soft hit less transpose than a hard one.
s.play.pitchVelocityCurve =
VelocityCurve::fromPoints({{0.0, 0.0}, {127.0, 1.0}}, CurveDomain::Bipolar);
Voice q;
Voice f;
q.start(60, 20, s);
f.start(60, 120, s);
q.renderFrame();
f.renderFrame();
const double quiet = static_cast<double>(q.renderFrame());
const double loud = static_cast<double>(f.renderFrame());
CHECK(quiet > 1.0);
CHECK(loud > quiet);
CHECK(loud < full); // velocity 120 is short of the +1 endpoint
}
// MAJOR-1 regression: MONO+LEGATO with a TRIGGER zone RE-ATTACKS after the last key is up.
// Trigger ignores note-off (Voice::release() is a no-op, so releasing_ never latches), so a
// legato guard keyed on `active && !releasing` saw a ringing one-shot as "still held" and
// silently RETUNED it in place. The correct predicate is the HELD-STACK depth: with no other
// key down, the next note is a fresh phrase and must restart the read head.
static void testMonoLegatoTriggerReattacksAfterKeyUp() {
SampleData s = rampSample(200000, 60);
s.play.playMode = PlayMode::Trigger; // default TriggerParams: full length, no fades
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(60, 127); // unity: read advances 1/frame
std::vector<AudioSample> out;
eng.render(out, 10);
eng.noteOff(60); // Trigger ignores the gate: keeps ringing...
CHECK(approx(probeFrame(eng), 10.0, 1e-4)); // ...read head still advancing past 10
eng.noteOn(62, 127); // NO key held -> fresh phrase: RE-ATTACK
CHECK(approx(probeFrame(eng), 0.0, 1e-4)); // read RESTARTED at 0 (a retune would read ~11)
// And it is genuinely playing from the top at the new pitch (ratio 2^(2/12) ~ 1.1225),
// not merely silent: the next frame reads at the advanced position.
CHECK(approx(probeFrame(eng), std::pow(2.0, 2.0 / 12.0), 1e-3));
}
// Companion boundary: with another key STILL physically held, a same-sample Trigger takeover
// under Legato still RETUNES (read continues) — the held-stack predicate matches the old
// behavior everywhere except the ringing-but-unheld case above.
static void testMonoLegatoTriggerHeldKeyStillRetunes() {
SampleData s = rampSample(200000, 60);
s.play.playMode = PlayMode::Trigger;
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(60, 127);
std::vector<AudioSample> out;
eng.render(out, 10);
eng.noteOn(62, 127); // 60 still held -> legato takeover
CHECK(approx(probeFrame(eng), 10.0, 1e-4)); // read CONTINUES at 10 — no re-attack
}
// MAJOR-2: allNotesOff releases every gated poly voice (flat release -> instant silence).
static void testAllNotesOffReleasesPolyVoices() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
SampleData km = (std::move(s));
VoiceEngine eng(4, km);
eng.noteOn(60, 127);
eng.noteOn(62, 127);
eng.noteOn(64, 127);
CHECK(eng.activeVoiceCount() == 3);
eng.allNotesOff();
CHECK(approx(probeFrame(eng), 0.0, 1e-9)); // all gated off (release 0 = instant)
CHECK(eng.activeVoiceCount() == 0);
}
// MAJOR-2, the STUCK-NOTE path: allNotesOff clears the mono held stack, so a phantom entry
// (simulating a LOST note-off) can never be resurrected by the fallback afterwards.
static void testAllNotesOffClearsMonoHeldStack() {
SampleData km = twoLevelSample();
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
eng.noteOn(50, kVelLow); // 50's note-off will never arrive (phantom)
eng.noteOn(70, kVelHigh); // 70 sounds, phantom 50 buried on the stack
eng.allNotesOff(); // PANIC
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
CHECK(eng.activeVoiceCount() == 0);
// The stack is empty: a fresh press + release gates off cleanly, with NO fallback
// restart of the phantom (pre-fix, noteOff(70) here re-struck 50 -> 0.25 forever).
eng.noteOn(70, kVelHigh);
CHECK(approx(probeFrame(eng), 0.75, 1e-6));
eng.noteOff(70);
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
CHECK(eng.activeVoiceCount() == 0);
}
// CC 120 (allSoundsOff) hard-stops a ringing TRIGGER one-shot that would otherwise play to
// its bounded playEnd (minutes on a full-length capture). This is the primary repro: allNotesOff
// (CC 123) is a NO-OP on a Trigger voice — only allSoundsOff provides the actual hard stop.
static void testAllSoundsOffStopsTriggerOneShot() {
// A Trigger sample with a very long play length (all-1 DC, flat velocity). After noteOn the
// voice is active and ringing; allSoundsOff must silence it immediately.
SampleData s = dcLevelSample(200000, 1.0f, 60);
s.play.playMode = PlayMode::Trigger;
s.play.trigger.lengthFraction = 1.0; // full length — would ring for 200000 frames
SampleData km = (std::move(s));
VoiceEngine eng(1, km);
eng.noteOn(60, 127);
CHECK(eng.activeVoiceCount() == 1);
// CC 123 (release) must be a NO-OP on a Trigger voice — the one-shot plays through.
eng.allNotesOff();
CHECK(eng.activeVoiceCount() == 1); // still ringing (Trigger ignores release)
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(out[0] > 0.5f); // still sounding
// CC 120 (hard-stop) must silence it instantly.
eng.allSoundsOff();
CHECK(eng.activeVoiceCount() == 0); // immediately idle
out.clear();
eng.render(out, 1);
CHECK(approx(out[0], 0.0, 1e-9)); // silent
}
// CC 123 (allNotesOff) still releases Gate voices — the existing release behavior is unchanged.
static void testAllNotesOffStillReleasesGateVoices() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
// Default Gate mode, instant release (releaseFrames 0).
SampleData km = (std::move(s));
VoiceEngine eng(4, km);
eng.noteOn(60, 127);
eng.noteOn(62, 127);
CHECK(eng.activeVoiceCount() == 2);
eng.allNotesOff();
std::vector<AudioSample> out;
eng.render(out, 1);
CHECK(approx(out[0], 0.0, 1e-9)); // Gate with 0-release: instant silence
CHECK(eng.activeVoiceCount() == 0);
}
// MONO LEGATO same-note re-press (one-held-note edge case): with only that note on the
// stack, heldCount_ after the re-push is 1 (not >= 2), so it falls through to re-attack
// rather than retune. This is the correct fresh-phrase behavior documented in the comment.
static void testMonoLegatoSameNoteRepressReattacks() {
SampleData s = rampSample(200000, 60);
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Legato);
eng.noteOn(60, 127); // first press; read starts at 0
std::vector<AudioSample> out;
eng.render(out, 10); // advance the read head to ~10
// Re-press the SAME note while it is the only held note: heldCount_ after removeHeld+push = 1
// -> does NOT satisfy heldCount_ >= 2 -> re-attack (not a legato retune).
eng.noteOn(60, 127);
CHECK(approx(probeFrame(eng), 0.0, 1e-4)); // read RESTARTED at 0 (re-attack, not retune)
}
// GREEN: out-of-range notes are rejected at BOTH mono entry points. The held stack stores
// uint8, so an unguarded off for note 256 (== 0 mod 256) would alias-evict held note 0 —
// losing its fallback. Note-ons out of [0,127] are a defined no-play.
static void testMonoOutOfRangeNotesRejected() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
SampleData km = (std::move(s));
VoiceEngine eng(2, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
CHECK(eng.noteOn(128, 127) == VoiceEngine::kNoVoice);
CHECK(eng.noteOn(-1, 127) == VoiceEngine::kNoVoice);
CHECK(eng.activeVoiceCount() == 0);
eng.noteOn(0, 127); // hold the aliasing target (note 0)
eng.noteOn(62, 127); // 62 takes the voice; 0 held beneath
eng.noteOff(256); // MUST NOT alias-evict held note 0
eng.noteOff(-256); // likewise for the negative wrap
CHECK(approx(probeFrame(eng), 1.0, 1e-6)); // 62 undisturbed
eng.noteOff(62); // falls back to STILL-HELD note 0
CHECK(approx(probeFrame(eng), 1.0, 1e-6)); // (alias-evicted pre-fix -> silence here)
eng.noteOff(0);
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
}
// The user-parameterized polyphony bound: an N-voice engine holds exactly N simultaneous
// notes and steals (never grows) on the N+1th; 0 clamps to the documented 1-voice degenerate.
static void testVoiceCountBoundsPolyphony() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
SampleData km = (std::move(s));
VoiceEngine e3(3, km);
CHECK(e3.maxVoices() == 3);
e3.noteOn(60, 127);
e3.noteOn(62, 127);
e3.noteOn(64, 127);
CHECK(e3.activeVoiceCount() == 3);
e3.noteOn(65, 127); // 4th: steals within the pool
CHECK(e3.activeVoiceCount() == 3);
VoiceEngine e1(1, km);
e1.noteOn(60, 127);
e1.noteOn(62, 127);
CHECK(e1.activeVoiceCount() == 1); // 1-voice pool: every note steals the one voice
VoiceEngine e0(0, km);
CHECK(e0.maxVoices() == 1); // documented degenerate: clamped to 1
}
// GA declick (bug 2): a MONO Retrigger TAKEOVER hard-cuts the sounding tone (read head +
// envelope restart in one frame) — pre-fix the output stepped from the old level to the new
// attack's ~0 in one sample, the audible click. With the engine's takeoverDeclick opt-in
// the boundary frame carries the old level and every later frame moves by a bounded small
// delta while the compensation decays under the new attack.
static void testMonoRetrigTakeoverDeclicksRestart() {
SampleData s = dcSample(200000, 60);
s.play.adsr.attackFrames = 100; // real attack: the new tone starts near 0
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 200); // past the attack: sustained at 1.0
CHECK(approx(pre.back(), 1.0, 1e-6));
eng.noteOn(64, 127); // Retrigger takeover: hard restart
std::vector<AudioSample> post;
eng.render(post, 400);
// No step at the boundary: the first post-takeover frame still carries the old level
// (pre-fix it was the new attack's ~0 — a full-scale step).
CHECK(approx(post[0], 1.0, 0.06));
// Bounded slope everywhere across the takeover: max per-frame delta is the declick decay
// step (~0.05) + the attack slope (0.01), never a click-sized jump.
double prev = static_cast<double>(pre.back());
double maxDelta = 0.0;
for (AudioSample v : post) {
const double d = std::fabs(static_cast<double>(v) - prev);
if (d > maxDelta) maxDelta = d;
prev = static_cast<double>(v);
}
CHECK(maxDelta < 0.07);
// The compensation dies out: the tail is the new note's sustain alone.
CHECK(approx(post.back(), 1.0, 1e-3));
}
// Peer restart site (peer-symmetry): the Retrigger FALLBACK on note-off — the most-recent
// still-held note re-strikes the voice — is the same hard cut and gets the same declick.
static void testMonoRetrigFallbackDeclicksRestart() {
SampleData s = dcSample(200000, 60);
s.play.adsr.attackFrames = 100;
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> a;
eng.render(a, 400); // 60 sustains at 1.0
eng.noteOn(64, 127); // takeover (declicked, settles back to 1.0)
std::vector<AudioSample> b;
eng.render(b, 400);
CHECK(approx(b.back(), 1.0, 1e-3));
eng.noteOff(64); // FALLBACK re-strikes held 60 — hard restart
std::vector<AudioSample> post;
eng.render(post, 400);
CHECK(approx(post[0], 1.0, 0.06)); // boundary carries the old level, no step
double prev = static_cast<double>(b.back());
double maxDelta = 0.0;
for (AudioSample v : post) {
const double d = std::fabs(static_cast<double>(v) - prev);
if (d > maxDelta) maxDelta = d;
prev = static_cast<double>(v);
}
CHECK(maxDelta < 0.07);
CHECK(approx(post.back(), 1.0, 1e-3));
}
// The declick is TAKEOVER-only: a fresh mono start (idle voice — first note of a phrase, or
// a re-press after a full gate-off) must NOT ramp from a stale last output; the attack starts
// at ~0 exactly as before.
static void testMonoDeclickOnlyOnTakeover() {
SampleData s = dcSample(200000, 60);
s.play.adsr.attackFrames = 100;
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
// First note of the phrase: no phantom compensation, attack from ~0.
eng.noteOn(60, 127);
CHECK(probeFrame(eng) < 0.02);
std::vector<AudioSample> a;
eng.render(a, 400); // sustain 1.0 (lastOut is now nonzero)
// Full gate-off (release 0 -> instant idle): the next start is FRESH, not a takeover.
eng.noteOff(60);
std::vector<AudioSample> gap;
eng.render(gap, 4);
CHECK(approx(gap.back(), 0.0, 1e-9));
eng.noteOn(62, 127);
CHECK(probeFrame(eng) < 0.02); // no declick from the stale last output
}
// Peer restart site (peer-symmetry): a POLY at-cap STEAL is the same hard cut as the mono
// retrig takeover — read head + envelope restart on a SOUNDING voice — and gets the same
// declick ramp. Pool of 1 makes the steal deterministic: the second note-on must steal the
// only (sounding) voice, and with the opt-in the boundary carries the old level instead of
// stepping to the new attack's ~0.
static void testPolyStealDeclicksRestart() {
SampleData s = dcSample(200000, 60);
s.play.adsr.attackFrames = 100;
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Poly, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 200); // past the attack: sustained at 1.0
CHECK(approx(pre.back(), 1.0, 1e-6));
CHECK(eng.noteOn(64, 127) != VoiceEngine::kNoVoice); // at cap: steals the sounding voice
std::vector<AudioSample> post;
eng.render(post, 400);
CHECK(approx(post[0], 1.0, 0.06)); // boundary carries the old level, no step
double prev = static_cast<double>(pre.back());
double maxDelta = 0.0;
for (AudioSample v : post) {
const double d = std::fabs(static_cast<double>(v) - prev);
if (d > maxDelta) maxDelta = d;
prev = static_cast<double>(v);
}
CHECK(maxDelta < 0.07);
CHECK(approx(post.back(), 1.0, 1e-3)); // compensation dies out; new note sustains
}
// SAME-BLOCK double takeover: two steals of the same voice with NO frame rendered between
// (a two-note chord arriving at cap in one block). The second start() must re-seed the ramp
// from the same pre-cut output level — if start() zeroed lastOut, the pending ramp would be
// dropped and the click would return on exactly this edge.
static void testSameBlockDoubleTakeoverKeepsDeclickSeed() {
SampleData s = dcSample(200000, 60);
s.play.adsr.attackFrames = 100;
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Poly, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 200); // sustained at 1.0
CHECK(approx(pre.back(), 1.0, 1e-6));
eng.noteOn(64, 127); // steal #1 (no render yet)
eng.noteOn(67, 127); // steal #2, same block
std::vector<AudioSample> post;
eng.render(post, 400);
CHECK(approx(post[0], 1.0, 0.06)); // seed survived the double restart
double prev = static_cast<double>(pre.back());
double maxDelta = 0.0;
for (AudioSample v : post) {
const double d = std::fabs(static_cast<double>(v) - prev);
if (d > maxDelta) maxDelta = d;
prev = static_cast<double>(v);
}
CHECK(maxDelta < 0.07);
CHECK(approx(post.back(), 1.0, 1e-3));
}
// Declick with a ZERO-ATTACK takeover onto the SAME DC level: the difference seed is
// (old level − new first raw output) = (1.0 − 1.0) = 0, so NOTHING is added — output stays
// exactly full scale, never above it. (This is the case the retired rev-1 (1 − amp) gate
// existed for: an ADDITIVE old-level ramp under an instant-unity attack summed to +6 dB.
// The difference seed makes the blip structurally impossible without any gate — and without
// the gate's fatal hole that kept the click on every instant-unity restart.)
static void testZeroAttackTakeoverNeverExceedsFullScale() {
SampleData s = dcSample(200000, 60);
s.play.adsr.attackFrames = 0; // zero-attack: amp == 1 on the very first frame
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 200); // sustained at 1.0
CHECK(approx(pre.back(), 1.0, 1e-6));
eng.noteOn(64, 127); // zero-attack takeover: amp hits 1 on frame 0
std::vector<AudioSample> post;
eng.render(post, 400);
// Every output frame must stay within [-1, 1]: no +6 dB blip.
for (AudioSample v : post) {
CHECK(v <= 1.0f + 1e-4f && v >= -1.0f - 1e-4f);
}
// The zero-attack note settles at sustain 1.0 immediately.
CHECK(approx(post[0], 1.0, 1e-4));
}
// Shared discontinuity probe for the GA2 click tests: max sample-to-sample delta from the
// last pre-restart frame across the whole post-restart span. A hard cut shows up as a
// click-sized step (~ the old instantaneous level); a properly declicked restart moves by
// the signal's own slope plus the ≤5%-of-seed decay step per frame.
static double maxDeltaAcross(double lastPre, const std::vector<AudioSample>& post) {
double prev = lastPre;
double maxDelta = 0.0;
for (AudioSample v : post) {
const double d = std::fabs(static_cast<double>(v) - prev);
if (d > maxDelta) maxDelta = d;
prev = static_cast<double>(v);
}
return maxDelta;
}
// GA2 — the click that SURVIVED the rev-1 declick (DAW report: "mono retrigger STILL
// CLICKS"): a mono Retrigger takeover of a TRIGGER zone. Trigger with no fade-in is at FULL
// amplitude on frame 0, so the rev-1 compensation — gated by (1 − amp) — was zeroed exactly
// here and the restart still hard-cut from the old instantaneous level (~1.0 at the sine
// peak) to the new onset's 0. The difference-seeded declick reproduces the old level on the
// boundary frame and bounds every later delta. A sine (not DC) so the test sees the real
// waveform-value jump the DC-sample rev-1 tests masked.
static void testMonoRetrigTriggerZoneDeclicksRestart() {
SampleData s = sineSample(48000, 100.0, 60); // period 480 frames; slope <= ~0.013/frame
s.play.playMode = PlayMode::Trigger; // default fades: NO fade-in -> amp 1 at frame 0
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 120); // quarter period: ringing at ~ the sine peak
CHECK(pre.back() > 0.99f); // the cut level is large — a real click pre-fix
eng.noteOn(60, 127); // hammer the same key: Retrigger takeover
std::vector<AudioSample> post;
eng.render(post, 400);
// Boundary continuity: the first post-restart frame reproduces the old level (pre-fix it
// stepped to the new onset's sin(0) == 0 — a full-scale discontinuity).
CHECK(std::fabs(static_cast<double>(post[0]) - static_cast<double>(pre.back())) < 0.01);
// Bounded slope across the whole restart: decay step (<= 0.05 of the seed) + sine slope.
CHECK(maxDeltaAcross(static_cast<double>(pre.back()), post) < 0.08);
}
// GA2 peer: the same gate hole on a GATE zone with ZERO attack (amp == 1 on frame 0 — the
// default AdsrParams, and any user-dialed instant attack). Rev-1's (1 − amp) gate zeroed the
// compensation here too; the difference seed closes it identically.
static void testZeroAttackGateRetrigNoStep() {
SampleData s = sineSample(48000, 100.0, 60);
s.play.adsr.attackFrames = 0; // instant-unity attack
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 0;
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 120); // ringing at ~ the sine peak
CHECK(pre.back() > 0.99f);
eng.noteOn(60, 127); // zero-attack Retrigger takeover
std::vector<AudioSample> post;
eng.render(post, 400);
CHECK(std::fabs(static_cast<double>(post[0]) - static_cast<double>(pre.back())) < 0.01);
CHECK(maxDeltaAcross(static_cast<double>(pre.back()), post) < 0.08);
}
// PREVIEW re-audition declick (GA2, re-homed on the engine): the preview is now a plain
// engine noteOn at the root, so re-auditioning while the first preview still rings is a
// POLY AT-CAP STEAL when the pool is saturated — with takeoverDeclick opted in (the shell's
// product default), the restart runs the same difference-seeded ramp: boundary continuity
// + bounded slope. Same physics testPolyStealDeclicksRestart pins; this pins it at the
// preview's exact shape (same note, root, full pool of 1).
static void testPreviewReauditionDeclicksViaEngineSteal() {
SampleData s = sineSample(48000, 100.0, 60); // default ADSR: instant unity (worst case)
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Poly, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
eng.noteOn(60, 127); // preview: root note through the pool
std::vector<AudioSample> pre;
eng.render(pre, 120); // ringing at ~ the sine peak
CHECK(pre.back() > 0.99f);
eng.noteOn(60, 127); // audition again: at-cap steal restart
std::vector<AudioSample> post;
eng.render(post, 400);
CHECK(std::fabs(static_cast<double>(post[0]) - static_cast<double>(pre.back())) < 0.01);
CHECK(maxDeltaAcross(static_cast<double>(pre.back()), post) < 0.08);
}
// GA-VoiceSteal repro (DAW bug): voiceCount 3, a triad note-on'd at the SAME sample time
// (three note-ons in one block, no render between), then a 4th note. The steal must take
// EXACTLY ONE voice (the oldest, none releasing) and leave the other two RINGING — the DAW
// symptom was every tone cutting out. Configured like the live instrument: Preserve engine
// (product default), a real OLA window, sine PCM, default-ish AHDSR (3 ms attack, sustain 1,
// 60 ms release), rendered stereo between events like process() does.
static void testOverCapChordStealsExactlyOne() {
SampleData s = sineSample(96000, 2000.0, 60); // ~2 s at 48k
s.play.adsr.attackFrames = 144; // 3 ms @ 48k
s.play.adsr.sustainLevel = 1.0;
s.play.adsr.releaseFrames = 2880; // 60 ms @ 48k
s.play.pitchEngine = PitchEngine::Preserve;
SampleData km = (std::move(s));
// Mirrors the processor: kPreserveVoiceCap = 8, 50 ms OLA window at 48k = 2400 frames.
VoiceEngine eng(3, km, /*preserveVoiceCap=*/8, /*preserveWindowFrames=*/2400);
// The chord: three note-ons at one sample time (same block, no render between).
CHECK(eng.noteOn(60, 100) != VoiceEngine::kNoVoice);
CHECK(eng.noteOn(64, 100) != VoiceEngine::kNoVoice);
CHECK(eng.noteOn(67, 100) != VoiceEngine::kNoVoice);
CHECK(eng.activeVoiceCount() == 3);
// Ring for a while (stereo, like the negotiated bus) — all three still sounding and finite.
std::vector<AudioSample> l(4800, 0.0f), r(4800, 0.0f);
eng.render(l.data(), r.data(), l.size());
CHECK(eng.activeVoiceCount() == 3);
bool finite = true;
for (AudioSample v : l) { if (!std::isfinite(v)) { finite = false; break; } }
CHECK(finite);
// The 4th note: must steal exactly ONE voice (the oldest = note 60) — never all.
CHECK(eng.noteOn(62, 100) != VoiceEngine::kNoVoice);
CHECK(eng.activeVoiceCount() == 3);
// Note 60 was the stolen one: its note-off finds no voice (count unchanged after the
// release window). Notes 64 and 67 must still hold their voices — each note-off drops
// the count by one once the 60 ms release tail has run out.
std::fill(l.begin(), l.end(), 0.0f); std::fill(r.begin(), r.end(), 0.0f);
eng.noteOff(60);
eng.render(l.data(), r.data(), l.size()); // 4800 frames > 2880 release
CHECK(eng.activeVoiceCount() == 3); // 60 no longer owns a voice: no-op
eng.noteOff(64);
std::fill(l.begin(), l.end(), 0.0f); std::fill(r.begin(), r.end(), 0.0f);
eng.render(l.data(), r.data(), l.size());
CHECK(eng.activeVoiceCount() == 2); // 64 was still ringing — ONE voice released
eng.noteOff(67);
std::fill(l.begin(), l.end(), 0.0f); std::fill(r.begin(), r.end(), 0.0f);
eng.render(l.data(), r.data(), l.size());
CHECK(eng.activeVoiceCount() == 1); // 67 was still ringing too
eng.noteOff(62);
std::fill(l.begin(), l.end(), 0.0f); std::fill(r.begin(), r.end(), 0.0f);
eng.render(l.data(), r.data(), l.size());
CHECK(eng.activeVoiceCount() == 0); // the stolen-into 4th note releases last
}
// PREVIEW OBEYS VOICING (the PreviewCard-isolation reversal): a preview is a plain engine
// noteOn, so it is a REAL pool voice — a full pool STEALS for it (never a parallel voice on
// top), it counts toward activeVoiceCount, and its note-off releases through the normal
// path. This is the processor's mailbox-drain contract, pinned in the pure core.
static void testPreviewNoteObeysVoicing() {
SampleData s = dcLevelSample(200000, 1.0f, 60);
SampleData km = (std::move(s));
VoiceEngine eng(2, km);
eng.noteOn(60, 127);
eng.noteOn(62, 127); // the pool is now FULL
eng.noteOn(64, 127); // the preview note: steals — no third voice
CHECK(eng.activeVoiceCount() == 2);
std::vector<AudioSample> buf(4, 0.0f);
eng.render(buf.data(), buf.size());
CHECK(approx(buf[0], 2.0, 1e-6)); // TWO voices sum — never 3 (no side-car)
eng.noteOff(64); // flat release: the preview gates off
std::vector<AudioSample> buf2(1, 0.0f);
eng.render(buf2.data(), buf2.size());
CHECK(eng.activeVoiceCount() == 1); // the surviving MIDI note still rings
CHECK(approx(buf2[0], 1.0, 1e-6));
}
// PREVIEW JOINS THE MONO HELD STACK: a preview routed through the real note path is a mono
// stack entry like any host note — it TAKES the single voice on press (last-note priority)
// and its release FALLS BACK to the still-held host note instead of cutting to silence.
// Pins the processor's mailbox-drain contract for Mono the way testPreviewNoteObeysVoicing
// pins it for Poly steal.
static void testPreviewNoteJoinsMonoHeldStack() {
SampleData km = twoLevelSample();
VoiceEngine eng(4, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger);
CHECK(eng.noteOn(50, kVelLow) == 0); // the host-MIDI note: zone A sounds
CHECK(approx(probeFrame(eng), 0.25, 1e-6));
CHECK(eng.noteOn(70, kVelHigh) == 0); // the preview press: TAKES the voice
CHECK(eng.activeVoiceCount() == 1); // still mono — the preview is no side-car
CHECK(approx(probeFrame(eng), 0.75, 1e-6));
eng.noteOff(70); // preview release: FALLBACK to the held note
CHECK(approx(probeFrame(eng), 0.25, 1e-6));
eng.noteOff(50); // host note up: gate off (flat release = instant)
CHECK(approx(probeFrame(eng), 0.0, 1e-9));
CHECK(eng.activeVoiceCount() == 0);
}
// PREVIEW NOTE-OFF ROUTES TO THE DRAIN ENGINE: mirror of process()'s dual-engine off
// routing. A preview held across a reload leaves its ringing voice in the DISPLACED
// (draining) snapshot while the fresh live engine has no voice at that pitch. The off is
// sent to BOTH — exactly what the mailbox drain does: the fresh engine must safely no-op,
// the drain engine must release its voice (otherwise the old-snapshot preview would
// sustain until the next reload hard-cut it).
static void testPreviewNoteOffRoutesToDrainEngine() {
SampleData km = twoLevelSample();
VoiceEngine drainEng(2, km); // was live when the preview fired
VoiceEngine liveEng(2, km); // the post-reload fresh snapshot: no voices
CHECK(drainEng.noteOn(70, kVelHigh) != VoiceEngine::kNoVoice);
CHECK(approx(probeFrame(drainEng), 0.75, 1e-6)); // the preview rings in the old snapshot
CHECK(liveEng.activeVoiceCount() == 0);
// The preview release, drained to BOTH engines like a host note-off:
liveEng.noteOff(70);
drainEng.noteOff(70);
CHECK(approx(probeFrame(liveEng), 0.0, 1e-9)); // fresh engine: safe no-op, stays silent
CHECK(liveEng.activeVoiceCount() == 0);
CHECK(approx(probeFrame(drainEng), 0.0, 1e-9)); // flat release: gates off NOW
CHECK(drainEng.activeVoiceCount() == 0); // the old-snapshot voice released
}
// GA2 — bounded-blend overshoot regression: mid-ramp output must stay within full scale.
//
// Construction of the worst case (§1 reviewer finding): retrig a sine at a point where the
// pre-cut level is ~1.0 (old ref ≈ 1). The new voice starts at sin(0) == 0, so the OLD
// frozen-seed declick adds (ref − x₀) ≈ 1.0 to the compensation. The new sine has a short
// period (8 frames) so outₙ reaches ~1.0 again within just 2 frames; at that moment the
// frozen seed is still ~0.9 → outₙ + seed ≈ 1.9, roughly +3.8 dB over full scale.
//
// The bounded blend keeps every frame within max(|ref|, |outCurrent|) ≤ 1.0 + tol — this
// test must FAIL against the rev-2 frozen-seed code and PASS with the bounded blend.
static void testDeclickBoundedBlendNoOvershoot() {
// A sine with 8-frame period so it peaks within the declick ramp window (~80 frames).
// 48000 frames, 6000 cycles -> period = 8 frames; quarter period = 2 frames = the peak.
const std::size_t kFrames = 48000;
const double kCycles = 6000.0; // period = 8 frames
SampleData s = sineSample(kFrames, kCycles, 60);
s.play.playMode = PlayMode::Trigger; // no fade-in -> amp 1 on frame 0 (worst case)
SampleData km = (std::move(s));
VoiceEngine eng(1, km, 0, 0, VoiceMode::Mono, MonoTrigger::Retrigger,
/*takeoverDeclick=*/true);
// Start a voice and render to a quarter period so the sine is near its positive peak.
// Period = 48000/6000 = 8 frames. Frame index 2 = sin(2π*6000*2/48000) = sin(π/2) = 1.0.
// We render 3 frames (indices 0,1,2 are visited: readPos 0→1→2→3) so pre[2] reads
// frame index 2 at the sine peak.
eng.noteOn(60, 127);
std::vector<AudioSample> pre;
eng.render(pre, 3); // frame index 2 (read on third render): sin(pi/2) ≈ 1.0
CHECK(pre.back() > 0.99f); // at peak: ref ≈ 1.0 when we cut
// Retrigger: hard restart at sin(0) == 0, ref == ~1.0. The frozen-seed approach would
// add ~0.9 to a new output of ~1.0 two frames later → ~1.9. The bounded blend must not.
eng.noteOn(60, 127);
const double tol = 1e-3;
std::vector<AudioSample> post;
eng.render(post, 200); // 200 frames covers the full ramp (~80 frames at kDeclickDecay=0.95)
for (std::size_t i = 0; i < post.size(); ++i) {
const double v = static_cast<double>(post[i]);
CHECK(v <= 1.0 + tol && v >= -1.0 - tol);
}
// Boundary identity: first frame must reproduce the pre-cut level (±small tol).
CHECK(std::fabs(static_cast<double>(post[0]) - static_cast<double>(pre.back())) < 0.01);
}
// ===========================================================================
// GA3 — Preserve tail wind-down: the final window (and the release riding over it) must be
// a gap-free tone. The GA2 tail clamp HELD THE LAST REAL SAMPLE as the shifter feed once the
// source ran out — a DC plateau with no waveform to correlate on. Splices landing in (or
// referenced against) that region were unalignable, so the tap alternated real-tone / dead-DC
// at the splice cadence: the DAW "periodic troughs, almost like ring modulation, stronger
// toward the end, ~1:20 tone-to-silence at the very end". GA3 freezes the WRITER instead
// (padding never enters the ring) and lets the aligned-splice machinery recycle the frozen
// real tail — these tests render to the natural end and assert the tone survives.
// ===========================================================================
// A sine at explicit per-index frequency f0 (cycles/frame). Period is chosen NON-INTEGER
// (splice alignment must earn the sub-sample fit) but dividing `frames` exactly, so the
// source ENDS at a zero crossing — the held-DC value the GA2 clamp would feed is ~0, making
// the pre-GA3 dead stretches measurable as near-silence.
static SampleData tailSine(std::size_t frames, double f0, int rootNote = 60) {
SampleData s;
s.frames.resize(frames);
for (std::size_t i = 0; i < frames; ++i) {
s.frames[i] = static_cast<float>(std::sin(2.0 * kPi * f0 * static_cast<double>(i)));
}
s.rootNote = rootNote;
return s;
}
// Longest run of consecutive frames with |x| < thresh in [from, to).
static std::size_t worstQuietRun(const std::vector<AudioSample>& out, std::size_t from,
std::size_t to, double thresh) {
std::size_t worst = 0, run = 0;
for (std::size_t i = from; i < to && i < out.size(); ++i) {
if (std::fabs(static_cast<double>(out[i])) < thresh) {
++run;
if (run > worst) worst = run;
} else {
run = 0;
}
}
return worst;
}
// Peak |x| over [from, from+len).
static double blockPeak(const std::vector<AudioSample>& out, std::size_t from, std::size_t len) {
double peak = 0.0;
for (std::size_t i = from; i < from + len && i < out.size(); ++i) {
const double a = std::fabs(static_cast<double>(out[i]));
if (a > peak) peak = a;
}
return peak;
}
// --- Gate no-loop, held to the natural end: the FINAL WINDOW carries the full-amplitude
// tone with no gaps, at up- AND down-shifts. Pre-GA3 this window chopped (RED without
// the writer freeze: quiet runs of hundreds of frames, block peaks collapsing to ~0.04). ---
static void testPreserveTailFinalWindowGapFree() {
const std::size_t frames = 8192;
const std::size_t w = 1024;
const double f0 = 1.0 / 163.84; // 50 exact cycles over 8192: ends at a zero crossing
const int notes[] = {67, 55}; // +7 st (ratio ~1.50) and -5 st (ratio ~0.75)
for (int note : notes) {
SampleData s = tailSine(frames, f0, 60);
s.play.pitchEngine = PitchEngine::Preserve; // Gate, no loop -> runs to the sample end
s.play.adsr = flatAdsr(); // held: amp 1 to the end (isolates the DSP)
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, static_cast<std::int64_t>(w));
eng.noteOn(note, 127);
std::vector<AudioSample> out;
eng.render(out, frames); // the voice frees exactly at the natural end
// (a) No dead stretches: a unit sine at period ~164/ratio dwells below 0.05 for only
// a few frames per zero crossing; the pre-GA3 DC stretches ran hundreds.
CHECK(worstQuietRun(out, frames - w, frames, 0.05) < 24);
// (b) Full amplitude to the very end: every 128-frame block in the final window spans
// more than a half period at both ratios, so a clean tone peaks near 1.0 in each.
for (std::size_t b = frames - w; b + 128 <= frames; b += 128) {
CHECK(blockPeak(out, b, 128) > 0.5);
}
}
}
// --- Gate release OVER the final window: the envelope scales amplitude smoothly; the
// underlying tone must stay continuous (no chop) while it fades. Adjacent-block peaks
// may only decay envelope-fast, never gap-fast. ---
static void testPreserveTailReleaseContinuous() {
const std::size_t frames = 8192;
const std::size_t w = 1024;
const double f0 = 1.0 / 163.84;
SampleData s = tailSine(frames, f0, 60);
s.play.pitchEngine = PitchEngine::Preserve;
s.play.adsr = flatAdsr();
s.play.adsr.releaseFrames = static_cast<std::int64_t>(w); // release spans the final window
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, static_cast<std::int64_t>(w));
eng.noteOn(67, 127);
std::vector<AudioSample> out;
eng.render(out, frames - w); // sustain up to one window before the end...
eng.noteOff(67); // ...then release exactly over the final window
eng.render(out, w);
// First release block still near full level; thereafter each 128-frame block may lose at
// most envelope-rate level vs its predecessor (linear release loses 12.5% of full scale
// per block). A pre-GA3 chop collapses a mid-release block toward zero and fails the
// ratio bound; assert down to a floor where the fade itself bottoms out.
const std::size_t r0 = frames - w;
CHECK(blockPeak(out, r0, 128) > 0.5);
double prev = blockPeak(out, r0, 128);
for (std::size_t b = r0 + 128; b + 128 <= frames; b += 128) {
const double cur = blockPeak(out, b, 128);
if (prev >= 0.15) CHECK(cur >= 0.3 * prev);
prev = cur;
}
}
// --- Trigger one-shot to its play end (lengthFraction < 1 exercises the playEnd_ feed bound):
// the final window BEFORE the stop point is gap-free at an off-root pitch. ---
static void testPreserveTriggerTailGapFree() {
const std::size_t frames = 8192;
const std::size_t w = 1024;
const double f0 = 1.0 / 163.84;
SampleData s = tailSine(frames, f0, 60);
s.play.pitchEngine = PitchEngine::Preserve;
s.play.playMode = PlayMode::Trigger;
s.play.trigger.lengthFraction = 0.8; // playEnd = 6554 (~40 exact cycles: ends near zero)
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, static_cast<std::int64_t>(w));
eng.noteOn(67, 127);
const std::size_t playEnd = 6554; // round(0.8 * 8192)
std::vector<AudioSample> out;
eng.render(out, playEnd);
CHECK(worstQuietRun(out, playEnd - w, playEnd, 0.05) < 24);
for (std::size_t b = playEnd - w; b + 128 <= playEnd; b += 128) {
CHECK(blockPeak(out, b, 128) > 0.5);
}
}
// --- Q-W0 T1-03: the Preserve prime is bounded by the PLAYABLE span. A Trigger zone whose
// play length is shorter than the OLA window must never carry source PAST the user's
// chosen stop into the ring — pre-fix, the prime pulled a full window bounded only by
// frameCount, and an up-shifted tap PLAYED the cut content (transposed) before the voice
// freed. The sample poisons everything past playEnd with amplitude 8: if any of it
// reaches the output, the peak bound fails. ---
static void testPreservePrimeStopsAtTriggerPlayEnd() {
const std::size_t frames = 8000;
const std::size_t w = 2048; // OLA window >> playable span
const std::size_t playLen = 500; // playEnd = round(8000 * 0.0625) = 500
SampleData s;
s.frames.resize(frames);
const double f0 = 1.0 / 50.0; // 10 cycles inside the playable span
for (std::size_t i = 0; i < frames; ++i) {
s.frames[i] = i < playLen
? static_cast<float>(std::sin(2.0 * kPi * f0 * static_cast<double>(i)))
: 8.0f; // POISON: cut content past the play end
}
s.rootNote = 60;
s.play.playMode = PlayMode::Trigger;
s.play.pitchEngine = PitchEngine::Preserve;
s.play.trigger.lengthFraction = 0.0625; // exactly 500 / 8000
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, static_cast<std::int64_t>(w));
eng.noteOn(72, 127); // +1 octave: the tap outruns the read head into
// the deepest primed history the ring holds
std::vector<AudioSample> out;
eng.render(out, playLen + 64); // through the voice's own end (readPos >= playEnd)
double peak = 0.0;
for (const AudioSample v : out) {
const double a = std::fabs(static_cast<double>(v));
if (a > peak) peak = a;
}
CHECK(peak < 1.5); // the 8.0 poison never sounds: nothing past playEnd entered the ring
CHECK(peak > 0.4); // ...and the real span genuinely played (the bound is not vacuous)
}
// --- Q-W0 T1-03 (companion): a whole sample SHORTER than the window (Gate, no loop) must not
// get zero padding declared as valid ring history — pre-fix, the prime zero-filled the
// window remainder with filled_ = window, so splices/tap travel landed in silence:
// hundreds-of-frames dead runs inside a sub-window one-shot (the pre-GA2 burst/gap
// artifact re-entering for short material). Post-fix the prime stops at the sample end
// and freezes the tail immediately, so the ring recycles ONLY real content. ---
static void testPreserveSubWindowSampleNoZeroPadInRing() {
const std::size_t frames = 1200; // sample < one window
const std::size_t w = 2048;
const double f0 = 1.0 / 96.0; // period 96: zero crossings dwell ~2 frames
SampleData s = tailSine(frames, f0, 60);
s.play.pitchEngine = PitchEngine::Preserve;
s.play.adsr = flatAdsr();
SampleData km = (std::move(s));
VoiceEngine eng(1, km, /*preserveCap=*/0, static_cast<std::int64_t>(w));
eng.noteOn(72, 127); // +1 octave up-shift (tap sweeps the whole ring)
std::vector<AudioSample> out;
eng.render(out, frames); // voice runs to its natural end (no loop)
// Pre-fix: the tap crossed the declared-valid zero pad repeatedly — quiet runs of 150+
// frames. Post-fix every relocation stays inside the real filled span; only sine zero
// crossings dip below the threshold.
CHECK(worstQuietRun(out, 0, frames, 0.05) < 30);
CHECK(blockPeak(out, 0, frames) > 0.5); // and it genuinely played at full level
}
int main() {
testEveryKeyPlaysTheLoadedCapture();
testUnplayableCaptureRefusesEveryNote();
testOutOfRangeNotesAreRefusedInMono();
testPitchRatioMath();
testKeyTrackedRatioMath();
testRepitchObservedPeriod();
testKeyTrackVarispeedObservedPeriod();
testKeyTrackPreserveShiftCollapsesAtZero();
testVelocityPitchIsExactlyOffByDefault();
testDrawnVelocityPitchCurveTransposesBothWays();
testAdsrShape();
testAdsrReleaseBeforeSustain();
testAdsrZeroAttackDecay();
testPolyphonicAllocation();
testNoteOffReleasesNewestSameNote();
testStealsReleasingVoiceFirst();
testStealsOldestWhenNoneReleasing();
testLoopSustainSeamless();
testZeroLengthLoopGoesSilent();
testSingleFrameLoop();
testAbsentLoopGoesSilent();
testStartFrameOffsetsInitialRead();
testStartFrameZeroIsUnchanged();
testStartFrameOutOfRangeClampsToZero();
testStartFrameWithLoop();
testStartAfterLoopEndWrapsIntoLoop();
testLoopReadWrapsSampleExactOverManyCycles();
testZeroCrossfadeLeavesTheSeamHard();
testCrossfadeBlendsMonotonelyAcrossTheRegion();
testSeamStepMatchesTheNaturalStepForAnyCrossfade();
testCrossfadeLengthFollowsItsParameter();
testCrossfadeIsSuppressedForALoopAtFrameZero();
testNoteOffDuringLoopSustainRunsTheReleaseAndFreesTheVoice();
testPreserveLoopsTheSourceSpanAtEveryTransposition();
testVelocityDefaultCurveIsFlatUnity();
testVelocityLinearCurveReproducesRamp();
testVelocityShapedCurveDrivesGain();
testPolyphonyMixesAdditively();
testChannelCount();
testStereoRenderKeepsChannelsDistinct();
testMonoSamplePlaysDualMonoInStereo();
testDualMonoStereoSampleRendersCentered();
testMonoRenderUnchangedByStereoData();
testStereoRenderAdvancesLikeMonoRepitch();
testStereoRenderSumsVoicesPerChannel();
testStereoRenderNullBufferIsNoOp();
testStereoStartFrameLoopShareOneReadHead();
// S15 — sampling modes.
testAhdsrHoldStageShape();
testAhdsrHoldZeroEqualsAdsr();
testTriggerLengthFractionFrames();
testTriggerLengthWithStart();
testTriggerAhdFadeShape();
testTriggerEdgeCases();
testTriggerIgnoresNoteOff();
// S16 — pitch engine + pitch envelope.
testPreserveDurationInvariance();
testVarispeedStillCouplesDuration();
testPitchEnvOffBitIdentical();
testPitchEnvOnBendsVarispeed();
testPreserveGateStereoLoopComposes();
testPreserveVoiceCap();
// FA1 postscript — the unity demotion is gone with the PreviewCard; the engine keeps a
// uniform Preserve onset at every note. Velocity under Preserve unchanged.
testPreserveUnityEngineVoiceSpeaksImmediately();
testPreserveTransposedVoiceSpeaksImmediately();
testPreserveUnityVoiceCountsTowardCap();
testVelocityCurveAppliesUnderPreserve();
// S12 review fix — per-zone A/D/S/R reaches the voice envelope.
testPerZoneAdsrReachesVoiceEnvelope();
testZeroAdsrIsInstantSustain();
// Phase S — voice count, MONO mode (held stack + Retrigger/Legato); preview as a real
// pool voice (PreviewCard retired — preview routes through the engine).
testMonoLastNotePriorityAndFallback();
testMonoReleaseOfLowerHeldNoteIsInaudible();
testMonoRepressHeldNoteMovesToTop();
testMonoRetriggerFallbackUsesOriginalVelocity();
testMonoOutOfRangeNeverJoinsStack();
testMonoRetriggerRestartsEnvelope();
testMonoLegatoContinuesEnvelope();
testMonoLegatoRetunesWithoutReadRestart();
testMonoLegatoAlwaysGlidesWithinThePhrase();
testMonoLegatoAfterReleaseReattacks();
testMonoIgnoresPreserveCap();
testMonoLegatoTriggerReattacksAfterKeyUp();
testMonoLegatoTriggerHeldKeyStillRetunes();
testAllNotesOffReleasesPolyVoices();
testAllNotesOffClearsMonoHeldStack();
testAllSoundsOffStopsTriggerOneShot();
testAllNotesOffStillReleasesGateVoices();
testMonoLegatoSameNoteRepressReattacks();
testMonoOutOfRangeNotesRejected();
testVoiceCountBoundsPolyphony();
testOverCapChordStealsExactlyOne();
testMonoRetrigTakeoverDeclicksRestart();
testMonoRetrigFallbackDeclicksRestart();
testMonoDeclickOnlyOnTakeover();
testPolyStealDeclicksRestart();
testSameBlockDoubleTakeoverKeepsDeclickSeed();
testZeroAttackTakeoverNeverExceedsFullScale();
testMonoRetrigTriggerZoneDeclicksRestart();
testZeroAttackGateRetrigNoStep();
testPreviewReauditionDeclicksViaEngineSteal();
testDeclickBoundedBlendNoOvershoot();
testPreviewNoteObeysVoicing();
testPreviewNoteJoinsMonoHeldStack();
testPreviewNoteOffRoutesToDrainEngine();
// GA3 — Preserve tail wind-down (writer freeze at source exhaustion).
testPreserveTailFinalWindowGapFree();
testPreserveTailReleaseContinuous();
testPreserveTriggerTailGapFree();
// Q-W0 T1-03 — the prime is bounded by the playable span (Trigger playEnd / sample end),
// with an immediate tail freeze on sub-window spans.
testPreservePrimeStopsAtTriggerPlayEnd();
testPreserveSubWindowSampleNoZeroPadInRing();
if (g_fail == 0) {
std::printf("all sampler_core tests passed\n");
return 0;
}
std::printf("%d sampler_core check(s) failed\n", g_fail);
return 1;
}
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