From 4f24f595207ffca61292af8e0d343b5ba1b35e44 Mon Sep 17 00:00:00 2001
From: Volker Fischer <corrados@users.noreply.github.com>
Date: Sun, 8 Aug 2021 17:27:03 +0200
Subject: proof of concept of using varying choke times of open hi-hat to
 support continuous hi-hat pedal changes

---
 src/audioinputenginemidi.cc | 31 +++++++++++++++++++++++++++++++
 src/inputprocessor.cc       | 23 +++++++++++++++++------
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/src/audioinputenginemidi.cc b/src/audioinputenginemidi.cc
index 00b6569..503a5c3 100644
--- a/src/audioinputenginemidi.cc
+++ b/src/audioinputenginemidi.cc
@@ -108,6 +108,11 @@ static const std::uint8_t TypeMask = 0xF0;
 // See:
 // https://www.midi.org/specifications-old/item/table-1-summary-of-midi-message
 
+
+// TODO better implementation: use member variable for controller value, set MIDI key on command line
+int hihat_controller = 0; // open hi-hat
+int hihat_midi_key   = 26;
+
 void AudioInputEngineMidi::processNote(const std::uint8_t* midi_buffer,
                                        std::size_t midi_buffer_length,
                                        std::size_t offset,
@@ -135,6 +140,18 @@ void AudioInputEngineMidi::processNote(const std::uint8_t* midi_buffer,
 				auto centered_velocity = (velocity-.5f)/127.0f;
 				events.push_back({ EventType::OnSet, (std::size_t)instrument_idx,
 				                   offset, centered_velocity, positional_information });
+
+// quick hack, add 1000000 to offset to transport hi-hat controller value
+auto instrument_idx1 = mmap.lookup(hihat_midi_key);
+if(instrument_idx == instrument_idx1)
+{
+  if(hihat_controller < 100) // quick hack: hard-coded value
+  {
+    events.push_back({ EventType::Choke, (std::size_t)instrument_idx,
+                       1000000 + hihat_controller, .0f, .0f });
+  }
+}
+
 			}
 		}
 		break;
@@ -164,6 +181,20 @@ void AudioInputEngineMidi::processNote(const std::uint8_t* midi_buffer,
 				// Return here to prevent reset of cached positional information.
 				return;
 			}
+
+			if(controller_number == 4) // hi-hat pedal
+			{
+
+// quick hack: if hi-hat control pedal is down, choke hi-hat instrument
+auto instrument_idx = mmap.lookup(hihat_midi_key);
+hihat_controller = value;
+if(value > 100 && instrument_idx != -1) // quick hack: hard-coded value
+{
+  events.push_back({ EventType::Choke, (std::size_t)instrument_idx,
+                     offset, .0f, .0f });
+}
+
+			}
 		}
 		break;
 
diff --git a/src/inputprocessor.cc b/src/inputprocessor.cc
index d8a7ff9..285daaa 100644
--- a/src/inputprocessor.cc
+++ b/src/inputprocessor.cc
@@ -168,8 +168,8 @@ static void applyChokeGroup(Settings& settings, DrumKit& kit,
 		for(auto& event_sample : events_ds.iterateOver<SampleEvent>(ch.num))
 		{
 			if(event_sample.group == instr.getGroup() &&
-			   event_sample.instrument_id != instrument_id &&
-			   event_sample.rampdown_count == -1) // Only if not already ramping.
+			   event_sample.instrument_id != instrument_id /*&&
+			   event_sample.rampdown_count == -1*/) // Only if not already ramping.
 			{
 				// Fixed group rampdown time of 68ms, independent of samplerate
 				applyChoke(settings, event_sample, 68, event.offset);
@@ -190,8 +190,8 @@ static void applyDirectedChoke(Settings& settings, DrumKit& kit,
 		{
 			for(auto& event_sample : events_ds.iterateOver<SampleEvent>(ch.num))
 			{
-				if(choke.instrument_id == event_sample.instrument_id &&
-				   event_sample.rampdown_count == -1) // Only if not already ramping.
+				if(choke.instrument_id == event_sample.instrument_id /*&&
+				   event_sample.rampdown_count == -1*/) // Only if not already ramping.
 				{
 					// choke.choketime is in ms
 					applyChoke(settings, event_sample, choke.choketime, event.offset);
@@ -355,11 +355,22 @@ bool InputProcessor::processChoke(event_t& event,
 	{
 		for(auto& event_sample : events_ds.iterateOver<SampleEvent>(ch.num))
 		{
-			if(event_sample.instrument_id == instrument_id &&
-			   event_sample.rampdown_count == -1) // Only if not already ramping.
+			if(event_sample.instrument_id == instrument_id /*&&
+			   event_sample.rampdown_count == -1*/) // Only if not already ramping.
 			{
 				// Fixed group rampdown time of 68ms, independent of samplerate
+
+// quick hack: all "Only if not already ramping" must be disabled for hi-hat pedal to work
+if(event.offset >= 1000000) // quick hack: added 1000000 to offset to transport hi-hat controller value
+{
+  int hihat_controller = event.offset - 1000000;
+  int rampdown_time = static_cast<int>(std::max(100.0, pow(10.0, (127.0 - hihat_controller) / 38.0))); // TODO optimize
+  applyChoke(settings, event_sample, rampdown_time, 0);
+}
+else
+{
 				applyChoke(settings, event_sample, 68, event.offset);
+}
 			}
 		}
 	}
-- 
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