63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
#include <GLFW/glfw3.h>
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#include <alsa/asoundlib.h>
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#include "log.h"
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#include "types.h"
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MidiDevice midi_open(char *name) {
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MidiDevice device;
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device.name = name;
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device.input = NULL;
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device.output = NULL;
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snd_rawmidi_open(&device.input, &device.output, name, SND_RAWMIDI_NONBLOCK);
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device.error = device.input == NULL || device.output == NULL;
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log_debug("(%s) MIDI open", name);
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return device;
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}
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void midi_write(MidiDevice device, unsigned char code, float value) {
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unsigned char buffer[3];
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buffer[0] = 0xB0;
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buffer[1] = code;
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buffer[2] = (unsigned char)(256 * value);
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snd_rawmidi_write(device.output, buffer, 3);
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}
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bool midi_background_listen(MidiDevice device, SharedContext *context,
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void (*event_callback)(unsigned char code,
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float value)) {
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pid_t pid;
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int bytes_read;
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unsigned char buffer[3];
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pid = fork();
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if (pid < 0) {
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log_error("Could not create subprocess");
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return false;
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}
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if (pid == 0) {
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return true;
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}
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log_info("(%s) background acquisition started (pid: %d)", device.name, pid);
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while (!context->stop) {
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bytes_read = snd_rawmidi_read(device.input, buffer, 3);
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if (bytes_read == 3) {
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event_callback(buffer[1], (float)buffer[2] / 256.0);
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log_debug("midi: %02x %d %.2f", buffer[0], buffer[1],
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(float)buffer[2] / 256);
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}
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}
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log_info("(%s) background acquisition stopped by main thread (pid: %d)",
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device.name, pid);
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return false;
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}
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