[model, ui] functional rate reduction

Ottobit/OttobitModel.cpp

@@ -4,28 +4,47 @@ namespace Example
 {
 void Ottobit::operator()(tick t)
 {
-  // Only compute bit factor when the control changes
+  // Only compute bit_factor when the control changes
   if (inputs.bits != previous_bits)
   {
     set_bit_factor();
     previous_bits = inputs.bits;
   }
 
+  // Only compute skipped_frames when the control changes
+  if (inputs.rate != previous_rate)
+  {
+    step_size = (1. - inputs.rate) * RATE;
+    previous_rate = inputs.rate;
+    qDebug() << "step size: " << step_size;
+  }
+
   // Process the input buffer
   for(int i = 0; i < inputs.audio.channels; i++)
   {
     auto* in = inputs.audio[i];
     auto* out = outputs.audio[i];
 
+    // Re-init skipped_frames and current_frame for each channel
+    skipped_frames = 0;
+    current_frame = in[0];
+
     for(int j = 0; j < t.frames; j++)
     {
-      if (inputs.bits != BITS)
-      {
-        int in_scaled{static_cast<int>((in[j] + 1) * bit_factor)};
-        current_frame = (static_cast<double>(in_scaled) / bit_factor) - 1;
-      }
+      if (skipped_frames <= step_size)
+        skipped_frames++;
       else
-        current_frame = in[j];
+      {
+        skipped_frames = 0;
+
+        if (inputs.bits == BITS)
+          current_frame = in[j];
+        else
+        {
+          int in_scaled{static_cast<int>((in[j] + 1) * bit_factor)};
+          current_frame = (static_cast<double>(in_scaled) / bit_factor) - 1;
+        }
+      }
 
       out[j] = current_frame;
     }

Ottobit/OttobitModel.hpp

@@ -13,6 +13,7 @@ namespace Example
 class Ottobit
 {
 #define BITS 16
+#define RATE 64
 
 public:
   halp_meta(name, "Ottobit")
@@ -29,6 +30,7 @@ public:
     {
       using mapper = halp::log_mapper<std::ratio<95, 100>>;
     } bits;
+    halp::knob_f32<"Rate", halp::range{.min = .1, .max = 1., .init = 1.}> rate;
   } inputs;
 
   struct
@@ -37,9 +39,13 @@ public:
   } outputs;
 
   // Local variables
-  double previous_bits;
-  int bit_factor;
-  double current_frame;
+  int bit_factor,
+      skipped_frames{0},
+      step_size{0};
+
+  double previous_bits{BITS},
+      previous_rate{1},
+      current_frame;
 
   void set_bit_factor();
 
@@ -47,7 +53,6 @@ public:
   void prepare(setup info)
   {
     // Initialization, this method will be called with buffer size, etc.
-    previous_bits = BITS;
     set_bit_factor();
   }
 

Ottobit/OttobitUi.hpp

@@ -10,10 +10,11 @@ struct Ottobit::ui
   using enum halp::layouts;
 
   halp_meta(name, "Ottobit")
-  halp_meta(layout, vbox)
+  halp_meta(layout, hbox)
   halp_meta(background, dark)
 
-  halp::label title{"Bits"};
   halp::item<&ins::bits> bits;
+
+  halp::item<&ins::rate> rate;
 };
 }