From 3b1f9e1767ef3042c91636dc432e6eb072ac10e4 Mon Sep 17 00:00:00 2001
From: dajiaohuang <mikewushuwen@outlook.com>
Date: Fri, 16 Oct 2026 07:23:41 +0800
Subject: [PATCH] Initialize oscillator history and AD envelope trigger state

---
 Source/Control/adenv.cpp                    |  2 +
 Source/Synthesis/oscillator.h               |  1 +
 tests/initialization/README.md              | 19 +++++++
 tests/initialization/tst_initialization.cpp | 62 +++++++++++++++++++++
 4 files changed, 84 insertions(+)
 create mode 100644 tests/initialization/README.md
 create mode 100644 tests/initialization/tst_initialization.cpp

diff --git a/Source/Control/adenv.cpp b/Source/Control/adenv.cpp
index 4e9568b7..422bcdcf 100644
--- a/Source/Control/adenv.cpp
+++ b/Source/Control/adenv.cpp
@@ -52,6 +52,8 @@ void AdEnv::Init(float sample_rate)
 {
     sample_rate_     = sample_rate;
     current_segment_ = ADENV_SEG_IDLE;
+    prev_segment_    = ADENV_SEG_IDLE;
+    trigger_         = 0;
     curve_scalar_    = 0.0f; // full linear
     phase_           = 0;
     min_             = 0.0f;
diff --git a/Source/Synthesis/oscillator.h b/Source/Synthesis/oscillator.h
index 469d09a0..87a552b9 100644
--- a/Source/Synthesis/oscillator.h
+++ b/Source/Synthesis/oscillator.h
@@ -56,6 +56,7 @@ class Oscillator
         pw_        = 0.5f;
         phase_     = 0.0f;
         phase_inc_ = CalcPhaseInc(freq_);
+        last_out_  = 0.0f;
         waveform_  = WAVE_SIN;
         eoc_       = true;
         eor_       = true;
diff --git a/tests/initialization/README.md b/tests/initialization/README.md
new file mode 100644
index 00000000..90b5fc10
--- /dev/null
+++ b/tests/initialization/README.md
@@ -0,0 +1,19 @@
+# Initialization regression tests
+
+These host-only tests exercise public oscillator and AD envelope initialization
+with synthetic samples. They do not open audio devices or require libDaisy.
+
+From the repository root, using CMake and a C++14 compiler:
+
+```sh
+cmake -S . -B build-host
+cmake --build build-host
+c++ -std=c++14 -I Source tests/initialization/tst_initialization.cpp build-host/libDaisySP.a -o test-initialization
+./test-initialization
+```
+
+The tests process a polyBLEP triangle, reinitialize the oscillator, and check
+that its integrator starts from zero. They also reinitialize an AD envelope
+with a pending trigger and verify that processing leaves it idle. Static test
+objects make the original failure deterministic without reading arbitrary
+uninitialized memory. Both cases run at 44.1, 48, and 96 kHz.
diff --git a/tests/initialization/tst_initialization.cpp b/tests/initialization/tst_initialization.cpp
new file mode 100644
index 00000000..7bfbe781
--- /dev/null
+++ b/tests/initialization/tst_initialization.cpp
@@ -0,0 +1,62 @@
+#include "daisysp.h"
+#include <cstdio>
+#include <initializer_list>
+
+using namespace daisysp;
+
+int main()
+{
+    // Static storage supplies a defined initial history, so the regression does
+    // not depend on the contents of uninitialized memory on the first run.
+    static Oscillator osc;
+    static AdEnv      env;
+    int               failures = 0;
+
+    for(float sample_rate : {44100.f, 48000.f, 96000.f})
+    {
+        osc.Init(sample_rate);
+        osc.SetWaveform(Oscillator::WAVE_POLYBLEP_TRI);
+        osc.SetFreq(220.f);
+        for(int i = 0; i < 64; ++i)
+            osc.Process();
+
+        osc.Init(sample_rate);
+        osc.SetWaveform(Oscillator::WAVE_POLYBLEP_TRI);
+        osc.SetFreq(220.f);
+        // At phase zero the corrected square input is zero. With the
+        // integrator initialized to zero, the first triangle sample is zero.
+        const float first = osc.Process();
+        if(first != 0.f)
+        {
+            std::printf("FAIL: triangle after Init(%.0f): %g, expected 0\n",
+                        sample_rate,
+                        first);
+            ++failures;
+        }
+
+        env.Init(sample_rate);
+        env.SetTime(ADENV_SEG_ATTACK, .01f);
+        env.Trigger();
+        // Reinitializing before processing must discard a pending trigger:
+        // Init documents the initial segment as idle.
+        env.Init(sample_rate);
+        for(int i = 0; i < 16; ++i)
+        {
+            const float output = env.Process();
+            if(output != 0.f || env.IsRunning())
+            {
+                std::printf(
+                    "FAIL: AD envelope after Init(%.0f): %g, segment %u\n",
+                    sample_rate,
+                    output,
+                    unsigned(env.GetCurrentSegment()));
+                ++failures;
+                break;
+            }
+        }
+    }
+
+    if(failures == 0)
+        std::puts("PASS: oscillator and AD envelope initialization");
+    return failures == 0 ? 0 : 1;
+}