Initial bypass implementation, MIDI only for now

plugins/Cardinal/src/HostAudio.cpp

@@ -139,7 +139,7 @@ struct HostAudio2 : HostAudio<2> {
         resetMeters = true;
     }
 
-    void processTerminalOutput(const ProcessArgs&)
+    void processTerminalOutput(const ProcessArgs&) override
     {
         const int blockFrames = pcontext->engine->getBlockFrames();
 

plugins/Cardinal/src/plugincontext.hpp

@@ -55,7 +55,7 @@ struct CardinalPluginContext : rack::Context {
     double sampleRate;
     float parameters[kModuleParameters];
     CardinalVariant variant;
-    bool playing, reset, bbtValid;
+    bool bypassed, playing, reset, bbtValid;
     int32_t bar, beat, beatsPerBar, beatType;
     uint64_t frame;
     double barStartTick, beatsPerMinute;

src/CardinalPlugin.cpp

@@ -343,6 +343,9 @@ struct Initializer
 
 void CardinalPluginContext::writeMidiMessage(const rack::midi::Message& message, const uint8_t channel)
 {
+    if (bypassed)
+        return;
+
     const size_t size = message.bytes.size();
     DISTRHO_SAFE_ASSERT_RETURN(size > 0,);
     DISTRHO_SAFE_ASSERT_RETURN(message.frame >= 0,);
@@ -429,6 +432,7 @@ class CardinalPlugin : public CardinalBasePlugin
    #if DISTRHO_PLUGIN_NUM_INPUTS != 0
     /* If host audio ins == outs we can get issues for inplace processing.
      * So allocate a float array that will serve as safe copy for those cases.
+     * Also used for bypass, so inputs are fully zero.
      */
     float** fAudioBufferCopy;
    #endif
@@ -439,6 +443,10 @@ class CardinalPlugin : public CardinalBasePlugin
     String fStateScreenshot;
     String fWindowSize;
 
+    // bypass handling
+    bool fWasBypassed;
+    MidiEvent bypassMidiEvents[16];
+
    #ifndef HEADLESS
     // real values, not VCV interpreted ones
     float fWindowParameters[kWindowParameterCount];
@@ -451,7 +459,8 @@ public:
          #if DISTRHO_PLUGIN_NUM_INPUTS != 0
           fAudioBufferCopy(nullptr),
          #endif
-          fPreviousFrame(0)
+          fPreviousFrame(0),
+          fWasBypassed(false)
     {
        #ifndef HEADLESS
         fWindowParameters[kWindowParameterShowTooltips] = 1.0f;
@@ -485,6 +494,16 @@ public:
             }
         } DISTRHO_SAFE_EXCEPTION("create unique temporary path");
 
+        // initialize midi events used when entering bypassed state
+        std::memset(bypassMidiEvents, 0, sizeof(bypassMidiEvents));
+
+        for (uint8_t i=0; i<16; ++i)
+        {
+            bypassMidiEvents[i].size = 3;
+            bypassMidiEvents[i].data[0] = 0xB0 + i;
+            bypassMidiEvents[i].data[1] = 0x7B;
+        }
+
         const float sampleRate = getSampleRate();
         rack::settings::sampleRate = sampleRate;
 
@@ -773,7 +792,7 @@ protected:
 
         // bypass
         if (index == kModuleParameters)
-            return 0.0f;
+            return context->bypassed ? 1.0f : 0.0f;
 
        #ifndef HEADLESS
         // window related parameters
@@ -797,7 +816,10 @@ protected:
 
         // bypass
         if (index == kModuleParameters)
+        {
+            context->bypassed = value > 0.5f;
             return;
+        }
 
        #ifndef HEADLESS
         // window related parameters
@@ -924,6 +946,8 @@ protected:
     {
         rack::contextSet(context);
 
+        const bool bypassed = context->bypassed;
+
         {
             const TimePosition& timePos(getTimePosition());
 
@@ -977,10 +1001,28 @@ protected:
         for (int i=0; i<DISTRHO_PLUGIN_NUM_OUTPUTS; ++i)
             std::memset(outputs[i], 0, sizeof(float)*frames);
 
-        context->midiEvents = midiEvents;
-        context->midiEventCount = midiEventCount;
+        if (bypassed)
+        {
+            if (fWasBypassed != bypassed)
+            {
+                context->midiEvents = bypassMidiEvents;
+                context->midiEventCount = 16;
+            }
+            else
+            {
+                context->midiEvents = nullptr;
+                context->midiEventCount = 0;
+            }
+        }
+        else
+        {
+            context->midiEvents = midiEvents;
+            context->midiEventCount = midiEventCount;
+        }
 
         context->engine->stepBlock(frames);
+
+        fWasBypassed = bypassed;
     }
 
     void bufferSizeChanged(const uint32_t newBufferSize) override

src/PluginContext.hpp

@@ -52,7 +52,7 @@ struct CardinalPluginContext : rack::Context {
     double sampleRate;
     float parameters[kModuleParameters];
     CardinalVariant variant;
-    bool playing, reset, bbtValid;
+    bool bypassed, playing, reset, bbtValid;
     int32_t bar, beat, beatsPerBar, beatType;
     uint64_t frame;
     double barStartTick, beatsPerMinute;
@@ -79,6 +79,7 @@ struct CardinalPluginContext : rack::Context {
          #else
           #error cardinal variant not set
          #endif
+          bypassed(false),
           playing(false),
           reset(false),
           bbtValid(false),