ALLEGRO_AUDIO_STREAM - Allegro 5 API
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#include <allegro5/allegro_audio.h>
typedef struct ALLEGRO_AUDIO_STREAM ALLEGRO_AUDIO_STREAM;
An ALLEGRO_AUDIO_STREAM object is used to stream generated audio to the sound
device, in real-time. This is done by reading from a buffer, which is split
into a number of fragments. Whenever a fragment has finished playing, the user
can refill it with new data.
As with ALLEGRO_SAMPLE_INSTANCE(3alleg5) objects, streams store information
necessary for playback, so you may not play the same stream multiple times
simultaneously. Streams also need to be attached to an ALLEGRO_MIXER(3alleg5),
which, eventually, reaches an ALLEGRO_VOICE(3alleg5) object.
While playing, you must periodically fill fragments with new audio data. To know
when a new fragment is ready to be filled, you can either directly check with
al_get_available_audio_stream_fragments(3alleg5), or listen to events from the
stream.
You can register an audio stream event source to an event queue; see
al_get_audio_stream_event_source(3alleg5). An
ALLEGRO_EVENT_AUDIO_STREAM_FRAGMENT(3alleg5) event is generated whenever a new
fragment is ready. When you receive an event, use
al_get_audio_stream_fragment(3alleg5) to obtain a pointer to the fragment to
be filled. The size and format are determined by the parameters passed to
al_create_audio_stream(3alleg5).
If you’re late with supplying new data, the stream will be silent until
new data is provided. You must call al_drain_audio_stream(3alleg5) when
you’re finished with supplying data to the stream.
If the stream is created by al_load_audio_stream(3alleg5) or
al_play_audio_stream(3alleg5) then it will also generate an
ALLEGRO_EVENT_AUDIO_STREAM_FINISHED(3alleg5) event if it reaches the end of
the file and is not set to loop.