audio: allow looping of streams with unknown length

panda/src/audiotraits/openalAudioManager.cxx

@@ -442,7 +442,7 @@ get_sound_data(MovieAudio *movie, int mode) {
     int channels = stream->audio_channels();
     int samples = (int)(stream->length() * stream->audio_rate());
     int16_t *data = new int16_t[samples * channels];
-    stream->read_samples(samples, data);
+    samples = stream->read_samples(samples, data);
     alBufferData(sd->_sample,
                  (channels>1) ? AL_FORMAT_STEREO16 : AL_FORMAT_MONO16,
                  data, samples * channels * 2, stream->audio_rate());

panda/src/audiotraits/openalAudioSound.cxx

@@ -373,7 +373,6 @@ read_stream_data(int bytelen, unsigned char *buffer) {
   nassertr(has_sound_data(), 0);
 
   MovieAudioCursor *cursor = _sd->_stream;
-  double length = cursor->length();
   int channels = cursor->audio_channels();
   int rate = cursor->audio_rate();
   int space = bytelen / (channels * 2);
@@ -381,7 +380,7 @@ read_stream_data(int bytelen, unsigned char *buffer) {
 
   while (space && (_loops_completed < _playing_loops)) {
     double t = cursor->tell();
-    double remain = length - t;
+    double remain = cursor->length() - t;
     if (remain > 60.0) {
       remain = 60.0;
     }
@@ -403,9 +402,20 @@ read_stream_data(int bytelen, unsigned char *buffer) {
     if (samples > _sd->_stream->ready()) {
       samples = _sd->_stream->ready();
     }
-    cursor->read_samples(samples, (int16_t *)buffer);
-    size_t hval = AddHash::add_hash(0, (uint8_t*)buffer, samples*channels*2);
-    audio_debug("Streaming " << cursor->get_source()->get_name() << " at " << t << " hash " << hval);
+    samples = cursor->read_samples(samples, (int16_t *)buffer);
+    if (audio_cat.is_debug()) {
+      size_t hval = AddHash::add_hash(0, (uint8_t*)buffer, samples*channels*2);
+      audio_debug("Streaming " << cursor->get_source()->get_name() << " at " << t << " hash " << hval);
+    }
+    if (samples == 0) {
+      _loops_completed += 1;
+      cursor->seek(0.0);
+      if (_playing_loops >= 1000000000) {
+        // Prevent infinite loop if endlessly looping empty sound
+        return fill;
+      }
+      continue;
+    }
     fill += samples;
     space -= samples;
     buffer += (samples * channels * 2);