Цель c — Использование (OSX) Core MIDI в проекте c ++

Большая часть CoreMIDI API — это простой старый C. Вы можете легко вызвать его из кода C ++, не делая ничего особенного.

(Документы Apple имеют язык переключения между «Swift» и «Objective-C», но не воспринимают «Objective-C» буквально. Это действительно означает «семейство C, либо C, либо Objective-C». Переключение на Swift показывает те же API, но в переведенной форме, видимой для Swift.)

В частности, см. CoreMIDI / MIDIServices.h.

Самым старым и простым фрагментом примера кода CoreMIDI, «Echo.cpp», на самом деле является C ++. Он считывает вход MIDI из всех источников и отправляет эти данные MIDI в первый доступный пункт назначения (на канале 1). Это очень грубо, но вы должны начать где-нибудь.

Скомпилировать:

clang Echo.cpp -framework CoreMIDI -framework CoreFoundation -o Echo

Код:

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#include <CoreMIDI/MIDIServices.h>
#include <CoreFoundation/CFRunLoop.h>
#include <stdio.h>

// ___________________________________________________________________________________________
// test program to echo MIDI In to Out
// ___________________________________________________________________________________________

MIDIPortRef     gOutPort = NULL;
MIDIEndpointRef gDest = NULL;
int             gChannel = 0;

static void MyReadProc(const MIDIPacketList *pktlist, void *refCon, void *connRefCon)
{
if (gOutPort != NULL && gDest != NULL) {
MIDIPacket *packet = (MIDIPacket *)pktlist->packet; // remove const (!)
for (unsigned int j = 0; j < pktlist->numPackets; ++j) {
for (int i = 0; i < packet->length; ++i) {
//              printf("%02X ", packet->data[i]);

// rechannelize status bytes
if (packet->data[i] >= 0x80 && packet->data[i] < 0xF0)
packet->data[i] = (packet->data[i] & 0xF0) | gChannel;
}

//          printf("\n");
packet = MIDIPacketNext(packet);
}

MIDISend(gOutPort, gDest, pktlist);
}
}

int     main(int argc, char *argv[])
{
if (argc >= 2) {
// first argument, if present, is the MIDI channel number to echo to (1-16)
sscanf(argv[1], "%d", &gChannel);
if (gChannel < 1) gChannel = 1;
else if (gChannel > 16) gChannel = 16;
--gChannel; // convert to 0-15
}

// create client and ports
MIDIClientRef client = NULL;
MIDIClientCreate(CFSTR("MIDI Echo"), NULL, NULL, &client);

MIDIPortRef inPort = NULL;
MIDIInputPortCreate(client, CFSTR("Input port"), MyReadProc, NULL, &inPort);
MIDIOutputPortCreate(client, CFSTR("Output port"), &gOutPort);

// enumerate devices (not really related to purpose of the echo program
// but shows how to get information about devices)
int i, n;
CFStringRef pname, pmanuf, pmodel;
char name[64], manuf[64], model[64];

n = MIDIGetNumberOfDevices();
for (i = 0; i < n; ++i) {
MIDIDeviceRef dev = MIDIGetDevice(i);

MIDIObjectGetStringProperty(dev, kMIDIPropertyName, &pname);
MIDIObjectGetStringProperty(dev, kMIDIPropertyManufacturer, &pmanuf);
MIDIObjectGetStringProperty(dev, kMIDIPropertyModel, &pmodel);

CFStringGetCString(pname, name, sizeof(name), 0);
CFStringGetCString(pmanuf, manuf, sizeof(manuf), 0);
CFStringGetCString(pmodel, model, sizeof(model), 0);
CFRelease(pname);
CFRelease(pmanuf);
CFRelease(pmodel);

printf("name=%s, manuf=%s, model=%s\n", name, manuf, model);
}

// open connections from all sources
n = MIDIGetNumberOfSources();
printf("%d sources\n", n);
for (i = 0; i < n; ++i) {
MIDIEndpointRef src = MIDIGetSource(i);
MIDIPortConnectSource(inPort, src, NULL);
}

// find the first destination
n = MIDIGetNumberOfDestinations();
if (n > 0)
gDest = MIDIGetDestination(0);

if (gDest != NULL) {
MIDIObjectGetStringProperty(gDest, kMIDIPropertyName, &pname);
CFStringGetCString(pname, name, sizeof(name), 0);
CFRelease(pname);
printf("Echoing to channel %d of %s\n", gChannel + 1, name);
} else {
printf("No MIDI destinations present\n");
}

CFRunLoopRun();
// run until aborted with control-C

return 0;
}