git.sesse.net Git - nageru/blob - midi_mapper.cpp

   1 #include "midi_mapper.h"
   2 #include "midi_mapping.pb.h"
   3
   4 #include <alsa/asoundlib.h>
   5 #include <google/protobuf/text_format.h>
   6 #include <google/protobuf/io/zero_copy_stream.h>
   7 #include <google/protobuf/io/zero_copy_stream_impl.h>
   8 #include <fcntl.h>
   9 #include <sys/eventfd.h>
  10
  11 #include <functional>
  12 #include <thread>
  13
  14 using namespace google::protobuf;
  15 using namespace std;
  16 using namespace std::placeholders;
  17
  18 namespace {
  19
  20 double map_controller_to_float(int val)
  21 {
  22         // Slightly hackish mapping so that we can represent exactly 0.0, 0.5 and 1.0.
  23         if (val <= 0) {
  24                 return 0.0;
  25         } else if (val >= 127) {
  26                 return 1.0;
  27         } else {
  28                 return (val + 0.5) / 127.0;
  29         }
  30 }
  31
  32 }  // namespace
  33
  34 MIDIMapper::MIDIMapper(ControllerReceiver *receiver)
  35         : receiver(receiver), mapping_proto(new MIDIMappingProto)
  36 {
  37         should_quit_fd = eventfd(/*initval=*/0, /*flags=*/0);
  38         assert(should_quit_fd != -1);
  39 }
  40
  41 MIDIMapper::~MIDIMapper()
  42 {
  43         should_quit = true;
  44         const uint64_t one = 1;
  45         write(should_quit_fd, &one, sizeof(one));
  46         midi_thread.join();
  47         close(should_quit_fd);
  48 }
  49
  50 bool load_midi_mapping_from_file(const string &filename, MIDIMappingProto *new_mapping)
  51 {
  52         // Read and parse the protobuf from disk.
  53         int fd = open(filename.c_str(), O_RDONLY);
  54         if (fd == -1) {
  55                 perror(filename.c_str());
  56                 return false;
  57         }
  58         io::FileInputStream input(fd);  // Takes ownership of fd.
  59         if (!TextFormat::Parse(&input, new_mapping)) {
  60                 input.Close();
  61                 return false;
  62         }
  63         input.Close();
  64         return true;
  65 }
  66
  67 void MIDIMapper::set_midi_mapping(const MIDIMappingProto &new_mapping)
  68 {
  69         lock_guard<mutex> lock(mapping_mu);
  70         if (mapping_proto) {
  71                 mapping_proto->CopyFrom(new_mapping);
  72         } else {
  73                 mapping_proto.reset(new MIDIMappingProto(new_mapping));
  74         }
  75
  76         num_controller_banks = min(max(mapping_proto->num_controller_banks(), 1), 5);
  77         current_controller_bank = 0;
  78 }
  79
  80 void MIDIMapper::start_thread()
  81 {
  82         midi_thread = thread(&MIDIMapper::thread_func, this);
  83 }
  84
  85 const MIDIMappingProto &MIDIMapper::get_current_mapping() const
  86 {
  87         lock_guard<mutex> lock(mapping_mu);
  88         return *mapping_proto;
  89 }
  90
  91 #define RETURN_ON_ERROR(msg, expr) do {                            \
  92         int err = (expr);                                          \
  93         if (err < 0) {                                             \
  94                 fprintf(stderr, msg ": %s\n", snd_strerror(err));  \
  95                 return;                                            \
  96         }                                                          \
  97 } while (false)
  98
  99
 100 void MIDIMapper::thread_func()
 101 {
 102         snd_seq_t *seq;
 103         int err;
 104
 105         RETURN_ON_ERROR("snd_seq_open", snd_seq_open(&seq, "default", SND_SEQ_OPEN_DUPLEX, 0));
 106         RETURN_ON_ERROR("snd_seq_nonblock", snd_seq_nonblock(seq, 1));
 107         RETURN_ON_ERROR("snd_seq_client_name", snd_seq_set_client_name(seq, "nageru"));
 108         RETURN_ON_ERROR("snd_seq_create_simple_port",
 109                 snd_seq_create_simple_port(seq, "nageru",
 110                         SND_SEQ_PORT_CAP_WRITE |
 111                         SND_SEQ_PORT_CAP_SUBS_WRITE,
 112                         SND_SEQ_PORT_TYPE_MIDI_GENERIC |
 113                         SND_SEQ_PORT_TYPE_APPLICATION));
 114
 115         // Listen to the announce port (0:1), which will tell us about new ports.
 116         RETURN_ON_ERROR("snd_seq_connect_from", snd_seq_connect_from(seq, 0, /*client=*/0, /*port=*/1));
 117
 118         // Now go through all ports and subscribe to them.
 119         snd_seq_client_info_t *cinfo;
 120         snd_seq_client_info_alloca(&cinfo);
 121
 122         snd_seq_client_info_set_client(cinfo, -1);
 123         while (snd_seq_query_next_client(seq, cinfo) >= 0) {
 124                 int client = snd_seq_client_info_get_client(cinfo);
 125
 126                 snd_seq_port_info_t *pinfo;
 127                 snd_seq_port_info_alloca(&pinfo);
 128
 129                 snd_seq_port_info_set_client(pinfo, client);
 130                 snd_seq_port_info_set_port(pinfo, -1);
 131                 while (snd_seq_query_next_port(seq, pinfo) >= 0) {
 132                         constexpr int mask = SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ;
 133                         if ((snd_seq_port_info_get_capability(pinfo) & mask) == mask) {
 134                                 subscribe_to_port(seq, *snd_seq_port_info_get_addr(pinfo));
 135                         }
 136                 }
 137         }
 138
 139         int num_alsa_fds = snd_seq_poll_descriptors_count(seq, POLLIN);
 140         unique_ptr<pollfd[]> fds(new pollfd[num_alsa_fds + 1]);
 141
 142         while (!should_quit) {
 143                 snd_seq_poll_descriptors(seq, fds.get(), num_alsa_fds, POLLIN);
 144                 fds[num_alsa_fds].fd = should_quit_fd;
 145                 fds[num_alsa_fds].events = POLLIN;
 146                 fds[num_alsa_fds].revents = 0;
 147
 148                 err = poll(fds.get(), num_alsa_fds + 1, -1);
 149                 if (err == 0 || (err == -1 && errno == EINTR)) {
 150                         continue;
 151                 }
 152                 if (err == -1) {
 153                         perror("poll");
 154                         break;
 155                 }
 156                 if (fds[num_alsa_fds].revents) {
 157                         // Activity on should_quit_fd.
 158                         break;
 159                 }
 160
 161                 // Seemingly we can get multiple events in a single poll,
 162                 // and if we don't handle them all, poll will _not_ alert us!
 163                 while (!should_quit) {
 164                         snd_seq_event_t *event;
 165                         err = snd_seq_event_input(seq, &event);
 166                         if (err < 0) {
 167                                 if (err == -EINTR) continue;
 168                                 if (err == -EAGAIN) break;
 169                                 fprintf(stderr, "snd_seq_event_input: %s\n", snd_strerror(err));
 170                                 return;
 171                         }
 172                         if (event) {
 173                                 handle_event(seq, event);
 174                         }
 175                 }
 176         }
 177 }
 178
 179 void MIDIMapper::handle_event(snd_seq_t *seq, snd_seq_event_t *event)
 180 {
 181         lock_guard<mutex> lock(mapping_mu);
 182         switch (event->type) {
 183         case SND_SEQ_EVENT_CONTROLLER: {
 184                 printf("Controller %d changed to %d\n", event->data.control.param, event->data.control.value);
 185
 186                 const int controller = event->data.control.param;
 187                 const float value = map_controller_to_float(event->data.control.value);
 188
 189                 // Global controllers.
 190                 match_controller(controller, MIDIMappingBusProto::kLocutFieldNumber, MIDIMappingProto::kLocutBankFieldNumber,
 191                         value, bind(&ControllerReceiver::set_locut, receiver, _2));
 192                 match_controller(controller, MIDIMappingBusProto::kLimiterThresholdFieldNumber, MIDIMappingProto::kLimiterThresholdBankFieldNumber,
 193                         value, bind(&ControllerReceiver::set_limiter_threshold, receiver, _2));
 194                 match_controller(controller, MIDIMappingBusProto::kMakeupGainFieldNumber, MIDIMappingProto::kMakeupGainBankFieldNumber,
 195                         value, bind(&ControllerReceiver::set_makeup_gain, receiver, _2));
 196
 197                 // Bus controllers.
 198                 match_controller(controller, MIDIMappingBusProto::kTrebleFieldNumber, MIDIMappingProto::kTrebleBankFieldNumber,
 199                         value, bind(&ControllerReceiver::set_treble, receiver, _1, _2));
 200                 match_controller(controller, MIDIMappingBusProto::kMidFieldNumber, MIDIMappingProto::kMidBankFieldNumber,
 201                         value, bind(&ControllerReceiver::set_mid, receiver, _1, _2));
 202                 match_controller(controller, MIDIMappingBusProto::kBassFieldNumber, MIDIMappingProto::kBassBankFieldNumber,
 203                         value, bind(&ControllerReceiver::set_bass, receiver, _1, _2));
 204                 match_controller(controller, MIDIMappingBusProto::kGainFieldNumber, MIDIMappingProto::kGainBankFieldNumber,
 205                         value, bind(&ControllerReceiver::set_gain, receiver, _1, _2));
 206                 match_controller(controller, MIDIMappingBusProto::kCompressorThresholdFieldNumber, MIDIMappingProto::kCompressorThresholdBankFieldNumber,
 207                         value, bind(&ControllerReceiver::set_compressor_threshold, receiver, _1, _2));
 208                 match_controller(controller, MIDIMappingBusProto::kFaderFieldNumber, MIDIMappingProto::kFaderBankFieldNumber,
 209                         value, bind(&ControllerReceiver::set_fader, receiver, _1, _2));
 210                 break;
 211         }
 212         case SND_SEQ_EVENT_NOTEON: {
 213                 const int note = event->data.note.note;
 214
 215                 printf("Note: %d\n", note);
 216
 217                 // Bank change commands. TODO: Highlight the bank change in the UI.
 218                 for (size_t bus_idx = 0; bus_idx < size_t(mapping_proto->bus_mapping_size()); ++bus_idx) {
 219                         const MIDIMappingBusProto &bus_mapping = mapping_proto->bus_mapping(bus_idx);
 220                         if (bus_mapping.has_prev_bank() &&
 221                             bus_mapping.prev_bank().note_number() == note) {
 222                                 current_controller_bank = (current_controller_bank + num_controller_banks - 1) % num_controller_banks;
 223                         }
 224                         if (bus_mapping.has_next_bank() &&
 225                             bus_mapping.next_bank().note_number() == note) {
 226                                 current_controller_bank = (current_controller_bank + 1) % num_controller_banks;
 227                         }
 228                         if (bus_mapping.has_select_bank_1() &&
 229                             bus_mapping.select_bank_1().note_number() == note) {
 230                                 current_controller_bank = 0;
 231                         }
 232                         if (bus_mapping.has_select_bank_2() &&
 233                             bus_mapping.select_bank_2().note_number() == note &&
 234                             num_controller_banks >= 2) {
 235                                 current_controller_bank = 1;
 236                         }
 237                         if (bus_mapping.has_select_bank_3() &&
 238                             bus_mapping.select_bank_3().note_number() == note &&
 239                             num_controller_banks >= 3) {
 240                                 current_controller_bank = 2;
 241                         }
 242                         if (bus_mapping.has_select_bank_4() &&
 243                             bus_mapping.select_bank_4().note_number() == note &&
 244                             num_controller_banks >= 4) {
 245                                 current_controller_bank = 3;
 246                         }
 247                         if (bus_mapping.has_select_bank_5() &&
 248                             bus_mapping.select_bank_5().note_number() == note &&
 249                             num_controller_banks >= 5) {
 250                                 current_controller_bank = 4;
 251                         }
 252                 }
 253
 254                 match_button(note, MIDIMappingBusProto::kToggleLocutFieldNumber, MIDIMappingProto::kToggleLocutBankFieldNumber,
 255                         bind(&ControllerReceiver::toggle_locut, receiver, _1));
 256                 match_button(note, MIDIMappingBusProto::kToggleAutoGainStagingFieldNumber, MIDIMappingProto::kToggleAutoGainStagingBankFieldNumber,
 257                         bind(&ControllerReceiver::toggle_auto_gain_staging, receiver, _1));
 258                 match_button(note, MIDIMappingBusProto::kToggleCompressorFieldNumber, MIDIMappingProto::kToggleCompressorBankFieldNumber,
 259                         bind(&ControllerReceiver::toggle_compressor, receiver, _1));
 260                 match_button(note, MIDIMappingBusProto::kClearPeakFieldNumber, MIDIMappingProto::kClearPeakBankFieldNumber,
 261                         bind(&ControllerReceiver::clear_peak, receiver, _1));
 262         }
 263         case SND_SEQ_EVENT_PORT_START:
 264                 subscribe_to_port(seq, event->data.addr);
 265                 break;
 266         case SND_SEQ_EVENT_PORT_EXIT:
 267                 printf("MIDI port %d:%d went away.\n", event->data.addr.client, event->data.addr.port);
 268                 break;
 269         case SND_SEQ_EVENT_NOTEOFF:
 270         case SND_SEQ_EVENT_CLIENT_START:
 271         case SND_SEQ_EVENT_CLIENT_EXIT:
 272         case SND_SEQ_EVENT_CLIENT_CHANGE:
 273         case SND_SEQ_EVENT_PORT_CHANGE:
 274         case SND_SEQ_EVENT_PORT_SUBSCRIBED:
 275         case SND_SEQ_EVENT_PORT_UNSUBSCRIBED:
 276                 break;
 277         default:
 278                 printf("Ignoring MIDI event of unknown type %d.\n", event->type);
 279         }
 280 }
 281
 282 void MIDIMapper::subscribe_to_port(snd_seq_t *seq, const snd_seq_addr_t &addr)
 283 {
 284         // Client 0 is basically the system; ignore it.
 285         if (addr.client == 0) {
 286                 return;
 287         }
 288
 289         int err = snd_seq_connect_from(seq, 0, addr.client, addr.port);
 290         if (err < 0) {
 291                 // Just print out a warning (i.e., don't die); it could
 292                 // very well just be e.g. another application.
 293                 printf("Couldn't subscribe to MIDI port %d:%d (%s).\n",
 294                         addr.client, addr.port, snd_strerror(err));
 295         } else {
 296                 printf("Subscribed to MIDI port %d:%d.\n", addr.client, addr.port);
 297         }
 298 }
 299
 300 void MIDIMapper::match_controller(int controller, int field_number, int bank_field_number, float value, function<void(unsigned, float)> func)
 301 {
 302         if (bank_mismatch(bank_field_number)) {
 303                 return;
 304         }
 305
 306         for (size_t bus_idx = 0; bus_idx < size_t(mapping_proto->bus_mapping_size()); ++bus_idx) {
 307                 const MIDIMappingBusProto &bus_mapping = mapping_proto->bus_mapping(bus_idx);
 308
 309                 const FieldDescriptor *descriptor = bus_mapping.GetDescriptor()->FindFieldByNumber(field_number);
 310                 const Reflection *bus_reflection = bus_mapping.GetReflection();
 311                 if (!bus_reflection->HasField(bus_mapping, descriptor)) {
 312                         continue;
 313                 }
 314                 const MIDIControllerProto &controller_proto =
 315                         static_cast<const MIDIControllerProto &>(bus_reflection->GetMessage(bus_mapping, descriptor));
 316                 if (controller_proto.controller_number() == controller) {
 317                         func(bus_idx, value);
 318                 }
 319         }
 320 }
 321
 322 void MIDIMapper::match_button(int note, int field_number, int bank_field_number, function<void(unsigned)> func)
 323 {
 324         if (bank_mismatch(bank_field_number)) {
 325                 return;
 326         }
 327
 328         for (size_t bus_idx = 0; bus_idx < size_t(mapping_proto->bus_mapping_size()); ++bus_idx) {
 329                 const MIDIMappingBusProto &bus_mapping = mapping_proto->bus_mapping(bus_idx);
 330
 331                 const FieldDescriptor *descriptor = bus_mapping.GetDescriptor()->FindFieldByNumber(field_number);
 332                 const Reflection *bus_reflection = bus_mapping.GetReflection();
 333                 if (!bus_reflection->HasField(bus_mapping, descriptor)) {
 334                         continue;
 335                 }
 336                 const MIDIButtonProto &button_proto =
 337                         static_cast<const MIDIButtonProto &>(bus_reflection->GetMessage(bus_mapping, descriptor));
 338                 if (button_proto.note_number() == note) {
 339                         func(bus_idx);
 340                 }
 341         }
 342 }
 343
 344 bool MIDIMapper::bank_mismatch(int bank_field_number)
 345 {
 346         const FieldDescriptor *bank_descriptor = mapping_proto->GetDescriptor()->FindFieldByNumber(bank_field_number);
 347         const Reflection *reflection = mapping_proto->GetReflection();
 348         return (reflection->HasField(*mapping_proto, bank_descriptor) &&
 349                 reflection->GetInt32(*mapping_proto, bank_descriptor) != current_controller_bank);
 350 }