jack-tools

commit 48f965ae8a00b74431d6498baae4cd900010900f
parent eeec4ad9d1a4658251efc5e120630748c9db756e
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Wed, 30 Dec 2020 20:47:04 +0000

polyphonic

Diffstat:
M
main.cpp
 | 
42
++++++++++++++++++++++++++++--------------

1 file changed, 28 insertions(+), 14 deletions(-)
diff --git a/main.cpp b/main.cpp
@@ -164,11 +164,14 @@ int cb_sample_rate(jack_nframes_t nframes, void* arg)
 	return 0;
 }
 
+static struct voice
+{
+	float envelope, freq, sample;
+} voices[128];
+
 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)
@@ -179,14 +182,10 @@ int cb_process(jack_nframes_t nframes, void* arg)
 		switch (event.buffer[0] >> 4 & 0x7)
 		{
 		case 0: // Note off
-			if (event.buffer[1] == note)
-				envelope = 0;
+			voices[event.buffer[1]].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;
+			voices[event.buffer[1]].envelope = event.buffer[2] / 128.f;
 			break;
 		default:
 			;
@@ -196,15 +195,21 @@ int cb_process(jack_nframes_t nframes, void* arg)
 	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;
+		float accum = 0;
+		for (auto& v : voices)
+		{
+			if (v.envelope < .02f)
+				continue;
+
+			accum += std::sin(v.sample * 6.28318530718f / srate) * v.envelope;
+			v.sample += v.freq;
+			if (v.sample >= srate)
+				v.sample -= srate;
+		}
+		audio_buf[i] = 2 / (1 + std::exp(accum)) - 1;
 	}
 	return 0;
 }
@@ -251,6 +256,15 @@ void print_sample_rate(void)
 
 int main()
 {
+	int note = 0;
+	for (auto& v : voices)
+	{
+		v.envelope = 0;
+		v.freq = 440 * std::pow(std::pow(2.f, 1.f/12), note++ - 69);
+
+		std::cout << v.freq << "Hz\n";
+	}
+
 	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);