annotate examples/basic_midi/render.cpp @ 407:5f3d7c23ffa7 prerelease

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/*
 * render.cpp
 *
 *  Created on: Oct 24, 2014
 *      Author: parallels
 */

#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;
	}
	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)
{

}