jack-tools

commit eeec4ad9d1a4658251efc5e120630748c9db756e
parent 473d45aa082af4cd8922bb69631efa52bd9ab296
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Wed, 30 Dec 2020 17:45:41 +0000

simple mono synthesizer

Diffstat:
M
main.cpp
 | 
119
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------

1 file changed, 102 insertions(+), 17 deletions(-)
diff --git a/main.cpp b/main.cpp
@@ -5,6 +5,8 @@
 #include <memory>
 #include <cassert>
 
+#include <cmath>
+
 #include <thread>
 #include <chrono>
 #include <iostream>
@@ -30,6 +32,14 @@ struct client
 	{
 		jack_set_process_callback(**this, cb, arg);
 	}
+	void set_buffer_size_callback(JackBufferSizeCallback cb, void* arg)
+	{
+		jack_set_buffer_size_callback(**this, cb, arg);
+	}
+	void set_sample_rate_callback(JackSampleRateCallback cb, void* arg)
+	{
+		jack_set_sample_rate_callback(**this, cb, arg);
+	}
 
 private:
 	static jack_client_t* create(char const* name, jack_options_t options)
@@ -135,48 +145,123 @@ private:
 }
 
 jack::client client("h-synth", JackNoStartServer);
-jack::port p1(client, "port1", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput | JackPortIsTerminal, 0);
+jack::port p1(client, "in", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
+jack::port p2(client, "out", JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
 
 jack::ringbuffer midi_data(1024);
 
 std::atomic_int midi_events;
+std::atomic<jack_nframes_t> buffer_size, sample_rate;
+
+int cb_buffer_size(jack_nframes_t nframes, void* arg)
+{
+	buffer_size = nframes;
+	return 0;
+}
+int cb_sample_rate(jack_nframes_t nframes, void* arg)
+{
+	sample_rate = nframes;
+	return 0;
+}
 
 int cb_process(jack_nframes_t nframes, void* arg)
 {
 	void* buf = jack_port_get_buffer(*p1, nframes);
+	static float envelope, freq;
+	static unsigned char note = 0xFF;
 
 	jack_midi_event_t event;
 	for (uint32_t i = 0; not jack_midi_event_get(&event, buf, i); ++i)
 	{
 		midi_data.write(event.buffer, event.size);
 		++midi_events;
+
+		switch (event.buffer[0] >> 4 & 0x7)
+		{
+		case 0: // Note off
+			if (event.buffer[1] == note)
+				envelope = 0;
+			break;
+		case 1: // Note on
+			note = event.buffer[1];
+			freq = 440 * pow(pow(2.f, 1.f/12), note - 69);
+			envelope = event.buffer[2];
+			envelope /= 128;
+			break;
+		default:
+			;
+		}
+	}
+
+	auto audio_buf = static_cast<float*>(jack_port_get_buffer(*p2, nframes));
+
+	int srate = sample_rate;
+	static float sample;
+
+	for (unsigned i = 0; i < buffer_size; ++i)
+	{
+		audio_buf[i] = std::sin(static_cast<float>(sample) * 6.28318530718f / srate) * envelope;
+		sample += freq;
+		if (sample >= srate)
+			sample -= srate;
+		//sample %= srate;
 	}
-//	midi_events.notify_all();
 	return 0;
 }
 
-int main()
+void print_midi_events(void)
 {
-	client.set_process_callback(cb_process, nullptr);
-	client.activate();
+	static int last = 0;
+	int current = midi_events;
 
-	int last = 0, current;
+	if (current == last)
+		return;
 
-	for (;;)
-	{
-		current = midi_events;
-		if (current == last)
-			continue;
+	last = current;
+	std::cout << "processed " << current << " MIDI events:\n" << std::hex;
+
+	for (unsigned char buf; midi_data.read(&buf, sizeof(buf)); /**/)
+		std::cout << std::setw(3) << +buf;
+
+	std::cout << std::dec << '\n';
+}
+
+void print_buffer_size(void)
+{
+	static int last = 0;
+	int current = buffer_size;
+
+	if (current == last)
+		return;
 
-		last = current;
+	last = current;
+	std::cout << "Buffer size changed to: " << current << '\n';
+}
+void print_sample_rate(void)
+{
+	static int last = 0;
+	int current = sample_rate;
 
-//		midi_events.wait();
-		std::cout << "processed " << midi_events << " MIDI events:\n" << std::hex;
+	if (current == last)
+		return;
 
-		for (unsigned char buf; midi_data.read(&buf, sizeof(buf)); /**/)
-			std::cout << std::setw(3) << +buf;
+	last = current;
+	std::cout << "Sample rate changed to: " << current << '\n';
+}
+
+int main()
+{
+	client.set_process_callback(cb_process, nullptr);
+	client.set_buffer_size_callback(cb_buffer_size, nullptr);
+	client.set_sample_rate_callback(cb_sample_rate, nullptr);
+	client.activate();
 
-		std::cout << std::dec << '\n';
+	for (;;)
+	{
+		std::this_thread::sleep_for(5ms);
+		print_buffer_size();
+		print_sample_rate();
+		print_midi_events();
 	}
 
 	return 0;