From fa0f4a2af7ef1c900e279ead72122f9d652b6959 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Tue, 26 Jan 2021 20:31:31 +0100
Subject: Add positional information to drumkit xml and sample class.

---
 src/audioinputenginemidi.cc | 77 ++++++++++++++++++++++++++++++---------------
 1 file changed, 52 insertions(+), 25 deletions(-)

(limited to 'src/audioinputenginemidi.cc')

diff --git a/src/audioinputenginemidi.cc b/src/audioinputenginemidi.cc
index 69aeeb6..0dee346 100644
--- a/src/audioinputenginemidi.cc
+++ b/src/audioinputenginemidi.cc
@@ -100,9 +100,13 @@ bool AudioInputEngineMidi::isValid() const
 static const std::uint8_t NoteOff = 0x80;
 static const std::uint8_t NoteOn = 0x90;
 static const std::uint8_t NoteAftertouch = 0xA0;
+static const std::uint8_t ControlChange = 0xB0;
 
 // Note type mask:
-static int const NoteMask = 0xF0;
+static const std::uint8_t TypeMask = 0xF0;
+
+// See:
+// https://www.midi.org/specifications-old/item/table-1-summary-of-midi-message
 
 void AudioInputEngineMidi::processNote(const std::uint8_t* midi_buffer,
                                        std::size_t midi_buffer_length,
@@ -114,38 +118,61 @@ void AudioInputEngineMidi::processNote(const std::uint8_t* midi_buffer,
 		return;
 	}
 
-	auto key = midi_buffer[1];
-	auto velocity = midi_buffer[2];
-	auto instrument_idx = mmap.lookup(key);
-	auto instruments = mmap.lookup(key);
-	for(const auto& instrument_idx : instruments)
+	switch(midi_buffer[0] & TypeMask)
 	{
-		switch(midi_buffer[0] & NoteMask)
-		{
-		case NoteOff:
-			// Ignore for now
-			break;
+	case NoteOff:
+		// Ignore for now
+		break;
 
-		case NoteOn:
-			if(velocity != 0)
+	case NoteOn:
+		{
+			auto key = midi_buffer[1];
+			auto velocity = midi_buffer[2];
+			auto instruments = mmap.lookup(key);
+			for(const auto& instrument_idx : instruments)
 			{
-				// maps velocities to [.5/127, 126.5/127]
-				auto centered_velocity = (velocity-.5f)/127.0f;
-				events.push_back({EventType::OnSet, (std::size_t)instrument_idx,
-				                  offset, centered_velocity});
+				if(velocity != 0)
+				{
+					// maps velocities to [.5/127, 126.5/127]
+					auto centered_velocity = (velocity-.5f)/127.0f;
+					events.push_back({EventType::OnSet, (std::size_t)instrument_idx,
+					                  offset, centered_velocity, positional_information});
+				}
 			}
-			break;
+		}
+		break;
 
-		case NoteAftertouch:
-			if(velocity > 0)
+	case NoteAftertouch:
+		{
+			auto key = midi_buffer[1];
+			auto velocity = midi_buffer[2];
+			auto instruments = mmap.lookup(key);
+			for(const auto& instrument_idx : instruments)
 			{
-				events.push_back({EventType::Choke, (std::size_t)instrument_idx,
-				                  offset, .0f});
+				if(velocity > 0)
+				{
+					events.push_back({EventType::Choke, (std::size_t)instrument_idx,
+					                  offset, .0f, .0f});
+				}
 			}
-			break;
+		}
+		break;
 
-		default:
-			break;
+	case ControlChange:
+		{
+			auto controller_number = midi_buffer[1];
+			auto value = midi_buffer[2];
+			if(controller_number == 16) // positional information
+			{
+				// Store value for use in next NoteOn event.
+				positional_information = value / 127.0f;
+
+				// Return here to prevent reset of cached positional information.
+				return;
+			}
 		}
 	}
+
+	// Clear cached positional information.
+	positional_information = 0.0f;
 }
-- 
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