Audio addon
TypesALLEGRO_AUDIO_DEPTH
Sample depth and type, and signedness. Mixers only use 32-bit signed float (-1..+1). The unsigned value is a bit-flag applied to the depth value.
For convenience:
ALLEGRO_AUDIO_DRIVER_ENUM
The sound driver to use. It is highly recommended to use ALLEGRO_AUDIO_DRIVER_AUTODETECT whenever possible.
ALLEGRO_AUDIO_PROPERTY
Flags to pass to the various al_*_get_* and al_*_set_* functions. Not all types will apply to all functions.
ALLEGRO_CHANNEL_CONF
Speaker configuration (mono, stereo, 2.1, 3, etc).
ALLEGRO_MIXER
A mixer is a type of stream which mixes together attached streams into a single buffer. ALLEGRO_MIXER_QUALITY
ALLEGRO_PLAYMODE
Sample and stream looping mode.
ALLEGRO_SAMPLE_ID
An ALLEGRO_SAMPLE_ID represents a sample being played via al_play_sample. It can be used to later stop the sample with al_stop_sample. ALLEGRO_SAMPLE
An ALLEGRO_SAMPLE object stores the data necessary for playing pre-defined digital audio. It holds information pertaining to data length, frequency, channel configuration, etc. You can have an ALLEGRO_SAMPLE object playing multiple times simultaneously. The object holds a user-specified PCM data buffer, of the format the object is created with. ALLEGRO_SAMPLE_INSTANCE
An ALLEGRO_SAMPLE_INSTANCE object represents a playable instance of a predefined sound effect. It holds information pertaining to the looping mode, loop start/end points, playing position, etc. An instance uses the data from an ALLEGRO_SAMPLE object. Multiple instances may be created from the same ALLEGRO_SAMPLE. An ALLEGRO_SAMPLE must not be destroyed while there are instances which reference it. To be played, an ALLEGRO_SAMPLE_INSTANCE object must be attached to an ALLEGRO_VOICE object, or to an ALLEGRO_MIXER object which is itself attached to an ALLEGRO_VOICE object (or to another ALLEGRO_MIXER object which is attached to an ALLEGRO_VOICE object, etc). An ALLEGRO_SAMPLE_INSTANCE object uses the following fields: XXX much of this will probably change soon
ALLEGRO_STREAM
An ALLEGRO_STREAM object is used to stream generated audio to the sound device, in real-time. As with ALLEGRO_SAMPLE_INSTANCE objects, they store information necessary for playback, so you may not play one multiple times simultaneously. They also need to be attached to an ALLEGRO_VOICE object, or to an ALLEGRO_MIXER object which, eventually, reaches an ALLEGRO_VOICE object. While playing, you must periodically supply new buffer data by first checking ALLEGRO_AUDIOPROP_USED_FRAGMENTS, then refilling the buffers via ALLEGRO_AUDIOPROP_BUFFER. If you're late with supplying new data, the object will be silenced until new data is provided. You must call al_drain_stream when you're finished supplying the stream. ALLEGRO_STREAM objects use the following fields:
ALLEGRO_VOICE
A voice structure that you'd attach a mixer or sample to. Ideally there would be one ALLEGRO_VOICE per system/hardware voice. Setting upal_install_audio
Parameters:
Returns zero on success, non-zero on failure. XXX the return value seems a bit out of place See also: al_reserve_samples. al_uninstall_audio
al_reserve_samples
Reserves 'reserve_samples' number of samples attached to the default mixer. al_install_audio must have been called first. If no default mixer is set, then this function will create a voice with an attached mixer. Returns true on success, false on error. Voice functionsal_create_voice
Creates a voice struct and allocates a voice from the digital sound driver. The sound driver's allocate_voice function should change the voice's frequency, depth, chan_conf, and settings fields to match what is actually allocated. If it cannot create a voice with exact settings it will fail. Use a mixer in such a case. al_destroy_voice
Destroys the voice and deallocates it from the digital driver. Does nothing if the voice is NULL. al_detach_voice
Detaches the sample or mixer stream from the voice. al_attach_stream_to_voice
Attaches an audio stream to a voice. The same rules as al_attach_sample_to_voice apply. This may fail if the driver can't create a voice with the buffer count and buffer size the stream uses. al_get_voice_bool
al_get_voice_enum
al_get_voice_long
al_set_voice_bool
al_set_voice_enum
al_set_voice_long
al_attach_mixer_to_voice
Attaches a mixer to a voice. The same rules as al_attach_sample_to_voice apply, with the exception of the depth requirement. al_attach_sample_to_voice
Attaches a sample to a voice, and allows it to play. The sample's volume and loop mode will be ignored, and it must have the same frequency and depth (including signed-ness) as the voice. This function may fail if the selected driver doesn't support preloading sample data. Sample functionsal_create_sample
Create a sample data structure from the supplied buffer. If al_destroy_sample
Free the sample data structure. If it was created with the You must destroy any ALLEGRO_SAMPLE_INSTANCE structures which reference this ALLEGRO_SAMPLE beforehand. al_play_sample
Plays a sample over the default mixer. al_reserve_samples must have previously been called. Returns true on success, false on failure. Playback may fail because all the reserved samples are currently used. al_stop_sample
Stop the sample started by al_play_sample. al_stop_samples
Stop all samples started by al_play_sample. al_create_sample_instance
Creates a sample stream, using the supplied data. This must be attached to a voice or mixer before it can be played. The argument may be NULL. You can then set the data later with al_set_sample. al_destroy_sample_instance
Detaches the sample stream from anything it may be attached to and frees it (the sample data is not freed!). al_play_sample_instance
Play an instance of a sample data. Returns true on success, false on failure. al_stop_sample_instance
al_get_sample_instance_bool
al_get_sample_instance_enum
al_get_sample_instance_float
al_get_sample_instance_long
al_get_sample_instance_ptr
al_get_sample
al_set_sample_instance_bool
al_set_sample_instance_enum
al_set_sample_instance_float
al_set_sample_instance_long
al_set_sample_instance_ptr
al_set_sample
Change the sample data that a sample plays. This can be quite an involved process. First, the sample is stopped if it is not already. Next, if data is NULL, the sample is detached from its parent (if any). If data is not NULL, the sample may be detached and reattached to its parent (if any). This is not necessary if the old sample data and new sample data have the same frequency, depth and channel configuration. Reattaching may not always succeed. On success, the sample remains stopped. The playback position and loop end points are reset to their default values. The loop mode remains unchanged. Returns zero on success, non-zero on failure. On failure, the sample will be stopped and detached from its parent. Mixer functionsal_create_mixer
Creates a mixer stream, to attach sample streams or other mixers to. It will mix into a buffer at the requested frequency and channel count. Only floating point mixing is currently supported. al_destroy_mixer
Destroys the mixer stream. al_get_default_mixer
Return the default mixer. al_set_default_mixer
Sets the default mixer. All samples started with al_play_sample will be stopped. If you are using your own mixer, this should be called before al_reserve_samples. Returns true on success, false on error. al_restore_default_mixer
Restores Allegro's default mixer. All samples started with al_play_sample will be stopped. Returns true on success, false on error. al_attach_mixer_to_mixer
Attaches a mixer onto another mixer. The same rules as with al_attach_sample_to_mixer apply, with the added caveat that both mixers must be the same frequency. al_attach_sample_to_mixer
al_attach_stream_to_mixer
al_get_mixer_bool
al_get_mixer_enum
al_get_mixer_long
al_set_mixer_bool
al_set_mixer_enum
al_set_mixer_long
al_mixer_set_postprocess_callback
Sets a post-processing filter function that's called after the attached streams have been mixed. The buffer's format will be whatever the mixer was created with. The sample count and user-data pointer is also passed. Stream functionsal_create_stream
Creates an audio stream, using the supplied values. The stream will be set to play by default. al_destroy_stream
al_drain_stream
Called by the user if sample data is not going to be passed to the stream any longer. This function waits for all pending buffers to finish playing. Stream's playing state will change to false. al_rewind_stream
Set the streaming file playing position to the beginning. Returns true on success. Currently this can only be called on streams created with acodec's [al_stream_from_file]. al_get_stream_bool
al_get_stream_enum
al_get_stream_float
al_get_stream_long
al_get_stream_ptr
al_set_stream_bool
al_set_stream_enum
al_set_stream_float
al_set_stream_long
al_set_stream_ptr
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Last updated: 2009-02-09 09:20:20Z