jack-tools

commit f5f0369625d186ad69f968453b7dfcb10f9543de
parent 48f965ae8a00b74431d6498baae4cd900010900f
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Wed, 30 Dec 2020 23:18:52 +0000

attack, delay, release & sustain

Diffstat:
M
main.cpp
 | 
59
++++++++++++++++++++++++++++++++++++++++++++++-------------

1 file changed, 46 insertions(+), 13 deletions(-)
diff --git a/main.cpp b/main.cpp
@@ -167,28 +167,43 @@ int cb_sample_rate(jack_nframes_t nframes, void* arg)
 static struct voice
 {
 	float envelope, freq, sample;
+	unsigned char active : 1, velocity : 7, state : 2;
 } voices[128];
 
 int cb_process(jack_nframes_t nframes, void* arg)
 {
+	static char sustain;
 	void* buf = jack_port_get_buffer(*p1, nframes);
 
 	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;
-
+		auto& voice = voices[event.buffer[1]];
 		switch (event.buffer[0] >> 4 & 0x7)
 		{
 		case 0: // Note off
-			voices[event.buffer[1]].envelope = 0;
-			break;
+			voice.active = 0;
+			continue;
 		case 1: // Note on
-			voices[event.buffer[1]].envelope = event.buffer[2] / 128.f;
-			break;
+			voice.active = 1;
+			voice.state = 2;
+			voice.velocity = event.buffer[2];
+			continue;
+		case 3: // Controller change
+			switch (event.buffer[1])
+			{
+			case 0x40: // Sustain
+				sustain = event.buffer[2] > 63;
+				if (not sustain)
+					for (auto& v : voices)
+						if (not v.active and v.state == 1)
+							v.state = 0;
+				continue;
+			}
+			/* FALLTHROUGH */
 		default:
-			;
+			midi_data.write(event.buffer, event.size);
+			++midi_events;
 		}
 	}
 
@@ -201,13 +216,33 @@ int cb_process(jack_nframes_t nframes, void* arg)
 		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;
+
+			float velocity = v.velocity / 127.f;
+
+			if (v.state == 2)
+			{
+				v.envelope += velocity / 5000.f;
+				if (v.envelope >= velocity)
+				{
+					v.envelope = velocity;
+					v.state = 1;
+				}
+			}
+			else if (v.state == 1)
+			{
+				v.envelope -= (v.envelope - velocity * 0.2f) * 0.00005f;
+				if (not (sustain || v.active))
+					v.state = 0;
+			}
+			else
+			{
+				v.velocity = 0;
+				v.envelope *= 0.9998f;
+			}
 		}
 		audio_buf[i] = 2 / (1 + std::exp(accum)) - 1;
 	}
@@ -261,8 +296,6 @@ int main()
 	{
 		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);