Fixes an issue that caused stuck notes and Fixes an issue that caused a crash when using a loop.

src/sfizz/ADSREnvelope.cpp

@@ -101,10 +101,18 @@ void ADSREnvelope::getBlockInternal(absl::Span<Float> output) noexcept
             if (releaseDelay > 0) {
                 // prevent computing the segment further than release point
                 size = std::min<size_t>(size, releaseDelay);
-            } else if (releaseDelay == 0 && delay < 0) {
+            } else if (releaseDelay == 0 && delay <= 0) {
+                if (delay < 0) {
+                    // release takes effect this frame
+                    currentState = State::Release;
+                } else {
+                    // release takes effect the next frame
+                    size = 1;
+                }
+                releaseDelay = -1;
+            } else if (releaseDelay == -1 && currentState < State::Release && delay <= 0) {
                 // release takes effect this frame
                 currentState = State::Release;
-                releaseDelay = -1;
             }
         }
 

src/sfizz/Voice.cpp

@@ -1188,7 +1188,7 @@ void Voice::Impl::fillWithData(AudioSpan<float> buffer) noexcept
         unsigned i = 0;
         while (i < numSamples) {
             int wrappedIndex = (*indices)[i] - loop.size * blockRestarts;
-            if (wrappedIndex > loop.end) {
+            while (wrappedIndex > loop.end) {
                 wrappedIndex -= loop.size;
                 blockRestarts += 1;
                 loop_.restarts += 1;

tests/SynthT.cpp

@@ -2160,3 +2160,46 @@ TEST_CASE("[Synth] Reuse offed voices in the last case scenario for new notes")
         REQUIRE( notes == std::vector<int> { i - 1, i } );
     }
 }
+
+TEST_CASE("[Synth] Note on and off at the maximum delay")
+{
+    sfz::Synth synth;
+    synth.setSampleRate(12800);
+    synth.setSamplesPerBlock(128);
+    sfz::AudioBuffer<float> buffer { 2, static_cast<unsigned>(synth.getSamplesPerBlock()) };
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/noteonoff.sfz", R"(
+        <region> loop_start=4 loop_end=124 ampeg_release=0.5 sample=looped_flute.wav
+    )");
+    synth.setNumVoices(128);
+    synth.noteOn(127, 64, 64);
+    CHECK(synth.getNumActiveVoices() == 1);
+    synth.noteOff(127, 64, 0);
+    CHECK(synth.getNumActiveVoices() == 1);
+    // Render for a while
+    for (int i = 0; i < 100; ++i)
+        synth.renderBlock(buffer);
+    CHECK(synth.getNumActiveVoices() == 0);
+}
+
+TEST_CASE("[Synth] Note on and off with delay")
+{
+    sfz::Synth synth;
+    synth.setSampleRate(12800);
+    synth.setSamplesPerBlock(128);
+    sfz::AudioBuffer<float> buffer { 2, static_cast<unsigned>(synth.getSamplesPerBlock()) };
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/noteonoff.sfz", R"(
+        <region> loop_start=4 loop_end=124 ampeg_release=0.5 sample=looped_flute.wav
+    )");
+    synth.setNumVoices(128);
+
+    int i;
+    for (i = 0; i < 127; ++i) {
+        synth.noteOn(i, i, 64);
+        synth.noteOff(i+1, i, 0);
+    }
+    CHECK(synth.getNumActiveVoices() == 127);
+    // Render for a while
+    for (int i = 0; i < 100; ++i)
+        synth.renderBlock(buffer);
+    CHECK(synth.getNumActiveVoices() == 0);
+}