annotate examples/05-Communication/basic-midi/render.cpp @ 543:8f8809c77dda prerelease

updated basics, digital, instruments, extras examples

/*
 ____  _____ _        _    
| __ )| ____| |      / \   
|  _ \|  _| | |     / _ \  
| |_) | |___| |___ / ___ \ 
|____/|_____|_____/_/   \_\

The platform for ultra-low latency audio and sensor processing

http://bela.io

A project of the Augmented Instruments Laboratory within the
Centre for Digital Music at Queen Mary University of London.
http://www.eecs.qmul.ac.uk/~andrewm

(c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
  Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
  Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.

The Bela software is distributed under the GNU Lesser General Public License
(LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
*/


#include <Bela.h>
#include <Midi.h>
#include <stdlib.h>
#include <rtdk.h>
#include <cmath>

float gFreq;
float gPhaseIncrement = 0;
bool gIsNoteOn = 0;
int gVelocity = 0;
float gSamplingPeriod = 0;

void midiMessageCallback(MidiChannelMessage message, void* arg){
	if(arg != NULL){
		rt_printf("Message from midi port %d: ", *(int*)arg);
	}
	message.prettyPrint();
	if(message.getType() == kmmNoteOn){
		gFreq = powf(2, (message.getDataByte(0)-69)/12.0f) * 440;
		gVelocity = message.getDataByte(1);
		gPhaseIncrement = 2 * M_PI * gFreq * gSamplingPeriod;
		gIsNoteOn = gVelocity > 0;
		rt_printf("v0:%f, ph: %6.5f, gVelocity: %d\n", gFreq, gPhaseIncrement, gVelocity);
	}
}
// setup() is called once before the audio rendering starts.
// Use it to perform any initialisation and allocation which is dependent
// on the period size or sample rate.
//
// userData holds an opaque pointer to a data structure that was passed
// in from the call to initAudio().
//
// Return true on success; returning false halts the program.
Midi midi;
int gMidiPort0 = 0;
bool setup(BelaContext *context, void *userData)
{
	midi.readFrom(gMidiPort0);
	midi.writeTo(gMidiPort0);
	midi.enableParser(true);
	midi.setParserCallback(midiMessageCallback, &gMidiPort0);
	if(context->analogFrames == 0) {
		rt_printf("Error: this example needs the analog I/O to be enabled\n");
		return false;
	}

	if(context->audioOutChannels <= 2 ||
		context->analogOutChannels <= 2){
		printf("Error: for this project, you need at least 2 analog and audio output channels.\n");
		return false;
	}

	gSamplingPeriod = 1/context->audioSampleRate;
	return true;
}

// render() is called regularly at the highest priority by the audio engine.
// Input and output are given from the audio hardware and the other
// ADCs and DACs (if available). If only audio is available, numMatrixFrames
// will be 0.


enum {kVelocity, kNoteOn, kNoteNumber};
void render(BelaContext *context, void *userData)
{
// one way of getting the midi data is to parse them yourself
//	(you should set midi.enableParser(false) above):
/*
	static midi_byte_t noteOnStatus = 0x90; //on channel 1
	static int noteNumber = 0;
	static int waitingFor = kNoteOn;
	static int playingNote = -1;
	int message;
	while ((message = midi.getInput()) >= 0){
		rt_printf("%d\n", message);
		switch(waitingFor){
		case kNoteOn:
			if(message == noteOnStatus){
				waitingFor = kNoteNumber;
			}
			break;
		case kNoteNumber:
			if((message & (1<<8)) == 0){
				noteNumber = message;
				waitingFor = kVelocity;
			}
			break;
		case kVelocity:
			if((message & (1<<8)) == 0){
				int _velocity = message;
				waitingFor = kNoteOn;
				// "monophonic" behaviour, with priority to the latest note on
				// i.e.: a note off from a previous note does not stop the current note
				// still you might end up having a key down and no note being played if you pressed and released another
				// key in the meantime
				if(_velocity == 0 && noteNumber == playingNote){
					noteOn = false;
					playingNote = -1;
					velocity = _velocity;
				} else if (_velocity > 0) {
					noteOn = true;
					velocity = _velocity;
					playingNote = noteNumber;
					f0 = powf(2, (playingNote-69)/12.0f) * 440;
					phaseIncrement = 2 * M_PI * f0 / context->audioSampleRate;
				}
				rt_printf("NoteOn: %d, NoteNumber: %d, velocity: %d\n", noteOn, noteNumber, velocity);
			}
			break;
		}
	}
*/
	/*
	int num;
	//alternatively, you can use the built-in parser (only processes channel messages at the moment).
	while((num = midi.getParser()->numAvailableMessages()) > 0){
		static MidiChannelMessage message;
		message = midi.getParser()->getNextChannelMessage();
		message.prettyPrint();
		if(message.getType() == kmmNoteOn){
			f0 = powf(2, (message.getDataByte(0)-69)/12.0f) * 440;
			velocity = message.getDataByte(1);
			phaseIncrement = 2 * M_PI * f0 / context->audioSampleRate;
			noteOn = velocity > 0;
			rt_printf("v0:%f, ph: %6.5f, velocity: %d\n", f0, phaseIncrement, gVelocity);
		}
	}
	 */
	// the following block toggles the LED on an Owl pedal
	// and asks the pedal to return the status of the LED
	// using MIDI control changes
	for(unsigned int n = 0; n < context->analogFrames; n++){
		static int count = 0;
		static bool state = 0;
		analogWriteOnce(context, n, 1, state);
		if(count % 40000 == 0){
			state = !state;
			midi_byte_t bytes[6] = {176, 30, (char)(state*127), 176, 67, 30}; // toggle the OWL led and ask for the led status
			midi.writeOutput(bytes, 6);
		}
		count++;
	}
	for(unsigned int n = 0; n < context->audioFrames; n++){
		if(gIsNoteOn == 1){
			static float phase = 0;
			phase += gPhaseIncrement;
			if(phase > 2 * M_PI)
				phase -= 2 * M_PI;
			float value = sinf(phase) * gVelocity/128.0f;
			audioWrite(context, n, 0, value);
			audioWrite(context, n, 1, value);
		} else {
			audioWrite(context, n, 0, 0);
			audioWrite(context, n, 1, 0);
		}
	}
}

// cleanup() is called once at the end, after the audio has stopped.
// Release any resources that were allocated in setup().

void cleanup(BelaContext *context, void *userData)
{

}