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instrument: one staged-envelope system — per-segment curves, the sustain-less AHD, and a shared overlay for all three envelopes

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Trigger's fade pair folds into the AHD (and goes live); the release anchors right;
Preserve rings its synthetic tail out instead of cutting it. Payload v10.
This commit is contained in:
Daniel Harvey
2026-07-31 08:37:57 -04:00
parent 87d7ceb066
commit 13e8c5c4d9
51 changed files with 3406 additions and 1812 deletions
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src/core/instrument/engine/voice.h
+49 -16
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@@ -60,7 +60,7 @@ inline double filterNormPerOctave() {
// kDeclickDecay/frame — so the boundary frame reproduces the old level exactly regardless of
// the new envelope's first value, and the residue fades to the -80 dB floor in a few ms.
// An earlier revision gated the compensation by (1 - newAmp): any restart whose new
// amplitude was instantly ~1 (Trigger with no fade-in, zero-attack Gate) got zero
// amplitude was instantly ~1 (a zero-attack Trigger or Gate) got zero
// compensation and kept the full click — the difference-seed has no such hole. Off by
// default so the bare core stays byte-identical to the pre-fix engine; the processor
// shell opts in.
@@ -162,25 +162,26 @@ private:
}
// This frame's amplitude in [0,1] from the active envelope. Gate: AHDSR ticks once per
// output frame (envelope time is wall-clock, independent of read rate). Trigger: fade
// shape is evaluated at the source offset (readPos - startFrame) so fades anchor to
// source frames regardless of pitch engine. Sets amplitudeDone_ on finish so
// advanceFrame frees the voice.
// output frame (envelope time is wall-clock, independent of read rate). Trigger: the AHD
// is evaluated at the source offset (readPos - startFrame) so its stages anchor to source
// frames regardless of pitch engine. Sets amplitudeDone_ on finish so advanceFrame frees
// the voice.
double tickAmplitude() {
double amp;
if (playMode_ == PlayMode::Gate) {
amp = env_.tick();
if (env_.finished()) amplitudeDone_ = true;
} else {
// Anchored to the source offset so fades land on the same source frames under
// either engine's read rate. The voice also frees on readPos_ >= playEnd_ in
// advanceFrame; finished() here is the belt to that suspenders.
amp = trigEnv_.amplitudeAt(readPos_ - static_cast<double>(startFrame_));
if (trigEnv_.finished()) amplitudeDone_ = true;
amp = ampAhd_.amplitudeAt(sourceOffset());
if (ampAhd_.finished()) amplitudeDone_ = true;
}
return amp;
}
// Frames into the Trigger play span at the current read head — the domain both
// sustain-less envelopes are evaluated over.
double sourceOffset() const { return readPos_ - static_cast<double>(startFrame_); }
// Advances the filter envelope and re-solves the corner from the modulated cutoff. The
// solve is UNQUANTIZED: the corner tracks the envelope continuously, so a sweep glides
// rather than staircasing. State preservation across the solve is voice_filter's own
@@ -195,8 +196,13 @@ private:
// through both so a moved base always re-solves.
void tickFilterCutoff() {
if (filterModAmount_ == 0.0 && filterSolved_) return;
double cut = static_cast<double>(filterBaseCutoff_) +
filterModAmount_ * filterEnv_.tick();
// The filter envelope takes the amp's shape under the active mode — AHDSR in Gate,
// the source-offset AHD in Trigger. playMode_ is fixed for the note's lifetime, so the
// branch is perfectly predicted.
const double envOut = (playMode_ == PlayMode::Gate)
? filterEnv_.tick()
: filterAhd_.amplitudeAt(sourceOffset());
double cut = static_cast<double>(filterBaseCutoff_) + filterModAmount_ * envOut;
if (cut < 0.0) cut = 0.0;
if (cut > 1.0) cut = 1.0;
const float cutNorm = static_cast<float>(cut);
@@ -284,6 +290,22 @@ private:
declickRefR_ > kDeclickFloor || declickRefR_ < -kDeclickFloor);
}
// Rings the voice's last rendered output out instead of hard-cutting it when the read head
// reaches the end of its span, on the PRESERVE path only. Varispeed's final sample is real
// source content at its natural end and its stop is left byte-identical; Preserve's is
// recycled synthetic tail (freezeTail stops the writer a full window before the read head
// arrives), whose level bears no relation to the source's own ending — cutting it at
// whatever amplitude the splice machinery happens to be at is the end-of-sample click.
// Reuses the takeover blend so the boundary frame reproduces the last level exactly.
void seedTerminalDeclick() {
if (pitchEngine_ != PitchEngine::Preserve) return;
declickRefL_ = (lastOutL_ > 1.0) ? 1.0 : (lastOutL_ < -1.0) ? -1.0 : lastOutL_;
declickRefR_ = (lastOutR_ > 1.0) ? 1.0 : (lastOutR_ < -1.0) ? -1.0 : lastOutR_;
declickWeight_ = 1.0;
declickActive_ = (declickRefL_ > kDeclickFloor || declickRefL_ < -kDeclickFloor ||
declickRefR_ > kDeclickFloor || declickRefR_ < -kDeclickFloor);
}
// Shared read/advance for both render paths: computes the interpolated per-channel
// value(s) at the current read head, ticks the amplitude + pitch envelopes once, applies
// the pitch engine, advances the head, and latches idle on exhaustion. `stereo` selects
@@ -327,6 +349,7 @@ private:
// byte-identical to the plain idle-out.
if (triggerRanOff || readPos_ >= static_cast<double>(frameCount)) {
if (declickPending_) seedDeclick();
if (!declickActive_) seedTerminalDeclick();
if (declickActive_) {
// Bounded blend at silence: outCurrent == 0, so the blend is
// w*(ref − 0) == w*ref. The weight decays by kDeclickDecay each frame,
@@ -350,6 +373,15 @@ private:
// Envelopes tick once per output frame. Pitch envelope biases pitch under either engine.
const double amp = tickAmplitude();
// Peer of the read-head exhaustion path above: a Trigger AHD whose stages end BEFORE
// the play span (a zero decay, which the shape deliberately keeps expressible) cuts the
// same synthetic Preserve tail at whatever level it was at. Seeded from lastOut, which
// still holds the PREVIOUS frame — this one is already silent. Gate is left out on
// purpose: its amplitude reaches zero through a release, so there is no cut to ring out.
if (amplitudeDone_ && amp == 0.0 && !declickActive_ &&
playMode_ == PlayMode::Trigger) {
seedTerminalDeclick();
}
const double gain = amp * velocityGain_;
const double pitchEnvSemis = pitchEnv_.tick();
@@ -518,13 +550,13 @@ private:
double readPos_ = 0.0; // fractional frame index into the sample
const SampleData* sample_ = nullptr;
// Gate uses env_ (AHDSR); Trigger uses trigEnv_ — only one active per voice (selected by
// Gate uses env_ (AHDSR); Trigger uses ampAhd_ — only one active per voice (selected by
// playMode_ at start). playEnd_ is Trigger's source-frame stop (frees when
// readPos_ >= playEnd_).
PlayMode playMode_ = PlayMode::Gate;
AdsrEnvelope env_;
TriggerEnvelope trigEnv_;
std::int64_t startFrame_ = 0; // clamped initial read frame; Trigger fade offset origin
AhdEnvelope ampAhd_;
std::int64_t startFrame_ = 0; // clamped initial read frame; the span-offset origin
std::int64_t playEnd_ = 0; // Trigger: source-frame end; Gate: unused
bool amplitudeDone_ = false; // set when the active amplitude envelope finished
@@ -534,7 +566,8 @@ private:
// solved once by start()'s prepare(), which is why every later re-solve is cutoff-only.
// filterRate_ <= 0 makes prepare() bypass rather than invent a rate.
instrument::engine::filter::VoiceFilter filter_;
AdsrEnvelope filterEnv_;
AdsrEnvelope filterEnv_; // Gate
AhdEnvelope filterAhd_; // Trigger
bool filterOn_ = false;
double filterRate_ = 0.0;
double filterCutoffNorm_ = 1.0;