portemento, adsr

Source/port.cpp

@@ -0,0 +1,34 @@
+/*
+  ==============================================================================
+
+    port.cpp
+    Created: 25 Oct 2025 2:09:16pm
+    Author:  mickl
+
+  ==============================================================================
+*/
+
+#include "port.h"
+#include "math.h"
+
+void Port::Init(float sample_rate, float htime)
+{
+    yt1_ = 0;
+    prvhtim_ = -100.0;
+    htime_ = htime;
+
+    sample_rate_ = sample_rate;
+    onedsr_ = 1.0 / sample_rate_;
+}
+
+float Port::Process(float in)
+{
+    if (prvhtim_ != htime_)
+    {
+        c2_ = powf(0.5, onedsr_ / htime_);
+        c1_ = 1.0 - c2_;
+        prvhtim_ = htime_;
+    }
+
+    return yt1_ = c1_ * in + c2_ * yt1_;
+}