Game Development Reference
In-Depth Information
sf::Music and sf::SoundStream
Playing an audio file using the
Music
class is as simple as:
When we open a music stream from a file, the supported audio formats are the same as they
are for
Sound
. Also,
Music::play()
launches the sound in another thread, so we don't
have to worry about blocking the current thread.
A music file can also be streamed from a loaded file in memory
(
Music::openFromMemory()
) or from
InputStream
(
Music::openFromStream()
).
Note how we
open from file
rather than
load from file
(as it is with
SoundBuffer
). The
music class derives from a class called
SoundStream
, which implements a common be-
havior to stream audio. It doesn't load all of the data in system memory, but it loads small
chunks of the whole asset and works with them. When it reaches an area of the audio that is
not in the memory, it requests more data from the stream and starts working with that. The
Music
class works on top of that interface and just provides methods to open a stream
(with the
Music::open*()
methods) and feeds these to the
SoundStream
beneath.
Since we are dealing with a data stream, the data cannot be destroyed while
SoundStream
is using it—when we use data which has already been allocated in system
memory, we have to be sure to keep it alive.
As mentioned earlier, the
Music
class doesn't provide much functionality over
SoundStream
, apart from methods which open file streams. All the interesting function-
ality is located in the base class,
SoundStream
, where methods such as
SoundStream::play()
,
SoundStream::pause()
, and
SoundStream::stop()
are located. These three methods work in the exact same way
as their cousins from the
Sound
class. The
SoundStream::setPlayingOffset()
and
SoundStream::setLoop()
methods are here as well.
