utilize lambda expression for callback

modules/audio/include/audio.h

@@ -81,32 +81,6 @@ bool startPlayback(AudioData *audioData);
  * to close.
  */
 void closeAudioFile(AudioData *audioData);
-
-/**
- * @brief Callback function for audio playback.
- *
- * This function is called by PortAudio when it needs more audio data to play.
- * It reads audio data from the file into the output buffer.
- *
- * @param input Pointer to the input buffer (not used in playback).
- * @param output Pointer to the output buffer where audio data should be
- * written.
- * @param frameCount Number of frames requested for playback.
- * @param timeInfo Pointer to timing information for the callback (not used in
- * this function).
- * @param statusFlags Flags indicating possible errors or other information from
- * PortAudio.
- * @param userData Pointer to user data provided when the stream was opened.
- *                 In this function, it should be a pointer to the AudioData
- * struct.
- *
- * @return paContinue if playback should continue, paComplete if playback is
- * complete.
- */
-static int playbackCallback(const void *input, void *output,
-                            unsigned long frameCount,
-                            const PaStreamCallbackTimeInfo *timeInfo,
-                            PaStreamCallbackFlags statusFlags, void *userData);
 #ifdef __cplusplus
 }
 #endif

modules/audio/src/audio.cpp

@@ -69,6 +69,26 @@ bool startPlayback(AudioData *audioData) {
       Pa_GetDeviceInfo(outputParameters.device)->defaultHighOutputLatency;
   outputParameters.hostApiSpecificStreamInfo = nullptr;
 
+  auto playbackCallback = [](const void *input, void *output, unsigned long frameCount,
+                             const PaStreamCallbackTimeInfo *timeInfo,
+                             PaStreamCallbackFlags statusFlags, void *userData) -> int {
+      float *out;
+      AudioData *audioData = (AudioData *)userData;
+      sf_count_t num_read;
+
+      out = (float *)output;
+      memset(out, 0, sizeof(float) * frameCount * audioData->info.channels);
+
+      num_read = sf_read_float(audioData->file, out,
+                              frameCount * audioData->info.channels);
+
+      if (num_read < frameCount) {
+        return paComplete;
+      }
+      return paContinue;
+  };
+
+
   err = Pa_OpenStream(&audioData->stream,
                       nullptr,  // No input
                       &outputParameters, audioData->info.samplerate,
@@ -106,45 +126,4 @@ void closeAudioFile(AudioData *audioData) {
   Pa_CloseStream(audioData->stream);
   Pa_Terminate();
   sf_close(audioData->file);
-}
-
-/**
- * @brief Callback function for audio playback.
- *
- * This function is called by PortAudio when it needs more audio data to play.
- * It reads audio data from the file into the output buffer.
- *
- * @param input Pointer to the input buffer (not used in playback).
- * @param output Pointer to the output buffer where audio data should be
- * written.
- * @param frameCount Number of frames requested for playback.
- * @param timeInfo Pointer to timing information for the callback (not used in
- * this function).
- * @param statusFlags Flags indicating possible errors or other information from
- * PortAudio.
- * @param userData Pointer to user data provided when the stream was opened.
- *                 In this function, it should be a pointer to the AudioData
- * struct.
- *
- * @return paContinue if playback should continue, paComplete if playback is
- * complete.
- */
-int playbackCallback(const void *input, void *output, unsigned long frameCount,
-                     const PaStreamCallbackTimeInfo *timeInfo,
-                     PaStreamCallbackFlags statusFlags, void *userData) {
-  float *out;
-  AudioData *audioData = (AudioData *)userData;
-  sf_count_t num_read;
-
-  out = (float *)output;
-  memset(out, 0, sizeof(float) * frameCount * audioData->info.channels);
-
-  num_read = sf_read_float(audioData->file, out,
-                           frameCount * audioData->info.channels);
-
-  if (num_read < frameCount) {
-    return paComplete;
-  }
-
-  return paContinue;
 }