Loading...
Searching...
No Matches

Abstract base class for streamed audio sources. More...

#include <SFML/Audio/SoundStream.hpp>

Inheritance diagram for sf::SoundStream:
sf::SoundSource sf::AudioResource sf::Music

Classes

struct  Chunk
 Structure defining a chunk of audio data to stream. More...
 

Public Types

enum class  Status { Stopped , Paused , Playing }
 Enumeration of the sound source states. More...
 
using EffectProcessor
 Callable that is provided with sound data for processing.
 

Public Member Functions

 ~SoundStream () override
 Destructor.
 
 SoundStream (SoundStream &&) noexcept
 Move constructor.
 
SoundStreamoperator= (SoundStream &&) noexcept
 Move assignment.
 
void play () override
 Start or resume playing the audio stream.
 
void pause () override
 Pause the audio stream.
 
void stop () override
 Stop playing the audio stream.
 
unsigned int getChannelCount () const
 Return the number of channels of the stream.
 
unsigned int getSampleRate () const
 Get the stream sample rate of the stream.
 
std::vector< SoundChannelgetChannelMap () const
 Get the map of position in sample frame to sound channel.
 
Status getStatus () const override
 Get the current status of the stream (stopped, paused, playing)
 
void setPlayingOffset (Time timeOffset)
 Change the current playing position of the stream.
 
Time getPlayingOffset () const
 Get the current playing position of the stream.
 
void setLooping (bool loop)
 Set whether or not the stream should loop after reaching the end.
 
bool isLooping () const
 Tell whether or not the stream is in loop mode.
 
void setEffectProcessor (EffectProcessor effectProcessor) override
 Set the effect processor to be applied to the sound.
 
void setPitch (float pitch)
 Set the pitch of the sound.
 
void setPan (float pan)
 Set the pan of the sound.
 
void setVolume (float volume)
 Set the volume of the sound.
 
void setSpatializationEnabled (bool enabled)
 Set whether spatialization of the sound is enabled.
 
void setPosition (const Vector3f &position)
 Set the 3D position of the sound in the audio scene.
 
void setDirection (const Vector3f &direction)
 Set the 3D direction of the sound in the audio scene.
 
void setCone (const Cone &cone)
 Set the cone properties of the sound in the audio scene.
 
void setVelocity (const Vector3f &velocity)
 Set the 3D velocity of the sound in the audio scene.
 
void setDopplerFactor (float factor)
 Set the doppler factor of the sound.
 
void setDirectionalAttenuationFactor (float factor)
 Set the directional attenuation factor of the sound.
 
void setRelativeToListener (bool relative)
 Make the sound's position relative to the listener or absolute.
 
void setMinDistance (float distance)
 Set the minimum distance of the sound.
 
void setMaxDistance (float distance)
 Set the maximum distance of the sound.
 
void setMinGain (float gain)
 Set the minimum gain of the sound.
 
void setMaxGain (float gain)
 Set the maximum gain of the sound.
 
void setAttenuation (float attenuation)
 Set the attenuation factor of the sound.
 
float getPitch () const
 Get the pitch of the sound.
 
float getPan () const
 Get the pan of the sound.
 
float getVolume () const
 Get the volume of the sound.
 
bool isSpatializationEnabled () const
 Tell whether spatialization of the sound is enabled.
 
Vector3f getPosition () const
 Get the 3D position of the sound in the audio scene.
 
Vector3f getDirection () const
 Get the 3D direction of the sound in the audio scene.
 
Cone getCone () const
 Get the cone properties of the sound in the audio scene.
 
Vector3f getVelocity () const
 Get the 3D velocity of the sound in the audio scene.
 
float getDopplerFactor () const
 Get the doppler factor of the sound.
 
float getDirectionalAttenuationFactor () const
 Get the directional attenuation factor of the sound.
 
bool isRelativeToListener () const
 Tell whether the sound's position is relative to the listener or is absolute.
 
float getMinDistance () const
 Get the minimum distance of the sound.
 
float getMaxDistance () const
 Get the maximum distance of the sound.
 
float getMinGain () const
 Get the minimum gain of the sound.
 
float getMaxGain () const
 Get the maximum gain of the sound.
 
float getAttenuation () const
 Get the attenuation factor of the sound.
 

Protected Member Functions

 SoundStream ()
 Default constructor.
 
void initialize (unsigned int channelCount, unsigned int sampleRate, const std::vector< SoundChannel > &channelMap)
 Define the audio stream parameters.
 
virtual bool onGetData (Chunk &data)=0
 Request a new chunk of audio samples from the stream source.
 
virtual void onSeek (Time timeOffset)=0
 Change the current playing position in the stream source.
 
virtual std::optional< std::uint64_t > onLoop ()
 Change the current playing position in the stream source to the beginning of the loop.
 

Detailed Description

Abstract base class for streamed audio sources.

Unlike audio buffers (see sf::SoundBuffer), audio streams are never completely loaded in memory.

Instead, the audio data is acquired continuously while the stream is playing. This behavior allows to play a sound with no loading delay, and keeps the memory consumption very low.

Sound sources that need to be streamed are usually big files (compressed audio musics that would eat hundreds of MB in memory) or files that would take a lot of time to be received (sounds played over the network).

sf::SoundStream is a base class that doesn't care about the stream source, which is left to the derived class. SFML provides a built-in specialization for big files (see sf::Music). No network stream source is provided, but you can write your own by combining this class with the network module.

A derived class has to override two virtual functions:

  • onGetData fills a new chunk of audio data to be played
  • onSeek changes the current playing position in the source

It is important to note that each SoundStream is played in its own separate thread, so that the streaming loop doesn't block the rest of the program. In particular, the onGetData and onSeek virtual functions may sometimes be called from this separate thread. It is important to keep this in mind, because you may have to take care of synchronization issues if you share data between threads.

Usage example:

class CustomStream : public sf::SoundStream
{
public:
[[nodiscard]] bool open(const std::string& location)
{
// Open the source and get audio settings
...
unsigned int channelCount = 2; // Stereo
unsigned int sampleRate = 44100; // 44100 Hz
// Initialize the stream -- important!
return true;
}
private:
bool onGetData(Chunk& data) override
{
// Fill the chunk with audio data from the stream source
// (note: must not be empty if you want to continue playing)
data.samples = ...;
// Return true to continue playing
data.sampleCount = ...;
return true;
}
void onSeek(sf::Time timeOffset) override
{
// Change the current position in the stream source
...
}
};
// Usage
CustomStream stream;
stream.open("path/to/stream");
stream.play();
Abstract base class for streamed audio sources.
void initialize(unsigned int channelCount, unsigned int sampleRate, const std::vector< SoundChannel > &channelMap)
Define the audio stream parameters.
virtual void onSeek(Time timeOffset)=0
Change the current playing position in the stream source.
virtual bool onGetData(Chunk &data)=0
Request a new chunk of audio samples from the stream source.
Represents a time value.
Definition Time.hpp:42
See also
sf::Music

Definition at line 51 of file SoundStream.hpp.

Member Typedef Documentation

◆ EffectProcessor

Initial value:
std::function<
void(const float* inputFrames, unsigned int& inputFrameCount, float* outputFrames, unsigned int& outputFrameCount, unsigned int frameChannelCount)>

Callable that is provided with sound data for processing.

When the audio engine sources sound data from sound sources it will pass the data through an effects processor if one is set. The sound data will already be converted to the internal floating point format.

Sound data that is processed this way is provided in frames. Each frame contains 1 floating point sample per channel. If e.g. the data source provides stereo data, each frame will contain 2 floats.

The effects processor function takes 4 parameters:

  • The input data frames, channels interleaved
  • The number of input data frames available
  • The buffer to write output data frames to, channels interleaved
  • The number of output data frames that the output buffer can hold
  • The channel count

The input and output frame counts are in/out parameters.

When this function is called, the input count will contain the number of frames available in the input buffer. The output count will contain the size of the output buffer i.e. the maximum number of frames that can be written to the output buffer.

Attempting to read more frames than the input frame count or write more frames than the output frame count will result in undefined behaviour.

It is important to note that the channel count of the audio engine currently sourcing data from this sound will always be provided in frameChannelCount. This can be different from the channel count of the sound source so make sure to size necessary processing buffers according to the engine channel count and not the sound source channel count.

When done processing the frames, the input and output frame counts must be updated to reflect the actual number of frames that were read from the input and written to the output.

The processing function should always try to process as much sound data as possible i.e. always try to fill the output buffer to the maximum. In certain situations for specific effects it can be possible that the input frame count and output frame count aren't equal. As long as the frame counts are updated accordingly this is perfectly valid.

If the audio engine determines that no audio data is available from the data source, the input data frames pointer is set to nullptr and the input frame count is set to 0. In this case it is up to the function to decide how to handle the situation. For specific effects e.g. Echo/Delay buffered data might still be able to be written to the output buffer even if there is no longer any input data.

An important thing to remember is that this function is directly called by the audio engine. Because the audio engine runs on an internal thread of its own, make sure access to shared data is synchronized appropriately.

Because this function is stored by the SoundSource object it will be able to be called as long as the SoundSource object hasn't yet been destroyed. Make sure that any data this function references outlives the SoundSource object otherwise use-after-free errors will occur.

Definition at line 154 of file SoundSource.hpp.

Member Enumeration Documentation

◆ Status

enum class sf::SoundSource::Status
stronginherited

Enumeration of the sound source states.

Enumerator
Stopped 

Sound is not playing.

Paused 

Sound is paused.

Playing 

Sound is playing.

Definition at line 54 of file SoundSource.hpp.

Constructor & Destructor Documentation

◆ ~SoundStream()

sf::SoundStream::~SoundStream ( )
override

Destructor.

◆ SoundStream() [1/2]

sf::SoundStream::SoundStream ( SoundStream && )
noexcept

Move constructor.

◆ SoundStream() [2/2]

sf::SoundStream::SoundStream ( )
protected

Default constructor.

This constructor is only meant to be called by derived classes.

Member Function Documentation

◆ getAttenuation()

float sf::SoundSource::getAttenuation ( ) const
nodiscardinherited

Get the attenuation factor of the sound.

Returns
Attenuation factor of the sound
See also
setAttenuation, getMinDistance

◆ getChannelCount()

unsigned int sf::SoundStream::getChannelCount ( ) const
nodiscard

Return the number of channels of the stream.

1 channel means a mono sound, 2 means stereo, etc.

Returns
Number of channels

◆ getChannelMap()

std::vector< SoundChannel > sf::SoundStream::getChannelMap ( ) const
nodiscard

Get the map of position in sample frame to sound channel.

This is used to map a sample in the sample stream to a position during spatialization.

Returns
Map of position in sample frame to sound channel

◆ getCone()

Cone sf::SoundSource::getCone ( ) const
nodiscardinherited

Get the cone properties of the sound in the audio scene.

Returns
Cone properties of the sound
See also
setCone

◆ getDirection()

Vector3f sf::SoundSource::getDirection ( ) const
nodiscardinherited

Get the 3D direction of the sound in the audio scene.

Returns
Direction of the sound
See also
setDirection

◆ getDirectionalAttenuationFactor()

float sf::SoundSource::getDirectionalAttenuationFactor ( ) const
nodiscardinherited

Get the directional attenuation factor of the sound.

Returns
Directional attenuation factor of the sound
See also
setDirectionalAttenuationFactor

◆ getDopplerFactor()

float sf::SoundSource::getDopplerFactor ( ) const
nodiscardinherited

Get the doppler factor of the sound.

Returns
Doppler factor of the sound
See also
setDopplerFactor

◆ getMaxDistance()

float sf::SoundSource::getMaxDistance ( ) const
nodiscardinherited

Get the maximum distance of the sound.

Returns
Maximum distance of the sound
See also
setMaxDistance, getAttenuation

◆ getMaxGain()

float sf::SoundSource::getMaxGain ( ) const
nodiscardinherited

Get the maximum gain of the sound.

Returns
Maximum gain of the sound
See also
setMaxGain, getAttenuation

◆ getMinDistance()

float sf::SoundSource::getMinDistance ( ) const
nodiscardinherited

Get the minimum distance of the sound.

Returns
Minimum distance of the sound
See also
setMinDistance, getAttenuation

◆ getMinGain()

float sf::SoundSource::getMinGain ( ) const
nodiscardinherited

Get the minimum gain of the sound.

Returns
Minimum gain of the sound
See also
setMinGain, getAttenuation

◆ getPan()

float sf::SoundSource::getPan ( ) const
nodiscardinherited

Get the pan of the sound.

Returns
Pan of the sound
See also
setPan

◆ getPitch()

float sf::SoundSource::getPitch ( ) const
nodiscardinherited

Get the pitch of the sound.

Returns
Pitch of the sound
See also
setPitch

◆ getPlayingOffset()

Time sf::SoundStream::getPlayingOffset ( ) const
nodiscard

Get the current playing position of the stream.

Returns
Current playing position, from the beginning of the stream
See also
setPlayingOffset

◆ getPosition()

Vector3f sf::SoundSource::getPosition ( ) const
nodiscardinherited

Get the 3D position of the sound in the audio scene.

Returns
Position of the sound
See also
setPosition

◆ getSampleRate()

unsigned int sf::SoundStream::getSampleRate ( ) const
nodiscard

Get the stream sample rate of the stream.

The sample rate is the number of audio samples played per second. The higher, the better the quality.

Returns
Sample rate, in number of samples per second

◆ getStatus()

Status sf::SoundStream::getStatus ( ) const
nodiscardoverridevirtual

Get the current status of the stream (stopped, paused, playing)

Returns
Current status

Implements sf::SoundSource.

◆ getVelocity()

Vector3f sf::SoundSource::getVelocity ( ) const
nodiscardinherited

Get the 3D velocity of the sound in the audio scene.

Returns
Velocity of the sound
See also
setVelocity

◆ getVolume()

float sf::SoundSource::getVolume ( ) const
nodiscardinherited

Get the volume of the sound.

Returns
Volume of the sound, in the range [0, 100]
See also
setVolume

◆ initialize()

void sf::SoundStream::initialize ( unsigned int channelCount,
unsigned int sampleRate,
const std::vector< SoundChannel > & channelMap )
protected

Define the audio stream parameters.

This function must be called by derived classes as soon as they know the audio settings of the stream to play. Any attempt to manipulate the stream (play(), ...) before calling this function will fail. It can be called multiple times if the settings of the audio stream change, but only when the stream is stopped.

Parameters
channelCountNumber of channels of the stream
sampleRateSample rate, in samples per second
channelMapMap of position in sample frame to sound channel

◆ isLooping()

bool sf::SoundStream::isLooping ( ) const
nodiscard

Tell whether or not the stream is in loop mode.

Returns
true if the stream is looping, false otherwise
See also
setLooping

◆ isRelativeToListener()

bool sf::SoundSource::isRelativeToListener ( ) const
nodiscardinherited

Tell whether the sound's position is relative to the listener or is absolute.

Returns
true if the position is relative, false if it's absolute
See also
setRelativeToListener

◆ isSpatializationEnabled()

bool sf::SoundSource::isSpatializationEnabled ( ) const
nodiscardinherited

Tell whether spatialization of the sound is enabled.

Returns
true if spatialization is enabled, false if it's disabled
See also
setSpatializationEnabled

◆ onGetData()

virtual bool sf::SoundStream::onGetData ( Chunk & data)
nodiscardprotectedpure virtual

Request a new chunk of audio samples from the stream source.

This function must be overridden by derived classes to provide the audio samples to play. It is called continuously by the streaming loop, in a separate thread. The source can choose to stop the streaming loop at any time, by returning false to the caller. If you return true (i.e. continue streaming) it is important that the returned array of samples is not empty; this would stop the stream due to an internal limitation.

Parameters
dataChunk of data to fill
Returns
true to continue playback, false to stop

Implemented in sf::Music.

◆ onLoop()

virtual std::optional< std::uint64_t > sf::SoundStream::onLoop ( )
protectedvirtual

Change the current playing position in the stream source to the beginning of the loop.

This function can be overridden by derived classes to allow implementation of custom loop points. Otherwise, it just calls onSeek(Time::Zero) and returns 0.

Returns
The seek position after looping (or std::nullopt if there's no loop)

Reimplemented in sf::Music.

◆ onSeek()

virtual void sf::SoundStream::onSeek ( Time timeOffset)
protectedpure virtual

Change the current playing position in the stream source.

This function must be overridden by derived classes to allow random seeking into the stream source.

Parameters
timeOffsetNew playing position, relative to the beginning of the stream

Implemented in sf::Music.

◆ operator=()

SoundStream & sf::SoundStream::operator= ( SoundStream && )
noexcept

Move assignment.

◆ pause()

void sf::SoundStream::pause ( )
overridevirtual

Pause the audio stream.

This function pauses the stream if it was playing, otherwise (stream already paused or stopped) it has no effect.

See also
play, stop

Implements sf::SoundSource.

◆ play()

void sf::SoundStream::play ( )
overridevirtual

Start or resume playing the audio stream.

This function starts the stream if it was stopped, resumes it if it was paused, and restarts it from the beginning if it was already playing. This function uses its own thread so that it doesn't block the rest of the program while the stream is played.

See also
pause, stop

Implements sf::SoundSource.

◆ setAttenuation()

void sf::SoundSource::setAttenuation ( float attenuation)
inherited

Set the attenuation factor of the sound.

The attenuation is a multiplicative factor which makes the sound more or less loud according to its distance from the listener. An attenuation of 0 will produce a non-attenuated sound, i.e. its volume will always be the same whether it is heard from near or from far. On the other hand, an attenuation value such as 100 will make the sound fade out very quickly as it gets further from the listener. The default value of the attenuation is 1.

Parameters
attenuationNew attenuation factor of the sound
See also
getAttenuation, setMinDistance

◆ setCone()

void sf::SoundSource::setCone ( const Cone & cone)
inherited

Set the cone properties of the sound in the audio scene.

The cone defines how directional attenuation is applied. The default cone of a sound is (2 * PI, 2 * PI, 1).

Parameters
coneCone properties of the sound in the scene
See also
getCone

◆ setDirection()

void sf::SoundSource::setDirection ( const Vector3f & direction)
inherited

Set the 3D direction of the sound in the audio scene.

The direction defines where the sound source is facing in 3D space. It will affect how the sound is attenuated if facing away from the listener. The default direction of a sound is (0, 0, -1).

Parameters
directionDirection of the sound in the scene
See also
getDirection

◆ setDirectionalAttenuationFactor()

void sf::SoundSource::setDirectionalAttenuationFactor ( float factor)
inherited

Set the directional attenuation factor of the sound.

Depending on the virtual position of an output channel relative to the listener (such as in surround sound setups), sounds will be attenuated when emitting them from certain channels. This factor determines how strong the attenuation based on output channel position relative to the listener is.

Parameters
factorNew directional attenuation factor to apply to the sound
See also
getDirectionalAttenuationFactor

◆ setDopplerFactor()

void sf::SoundSource::setDopplerFactor ( float factor)
inherited

Set the doppler factor of the sound.

The doppler factor determines how strong the doppler shift will be.

Parameters
factorNew doppler factor to apply to the sound
See also
getDopplerFactor

◆ setEffectProcessor()

void sf::SoundStream::setEffectProcessor ( EffectProcessor effectProcessor)
overridevirtual

Set the effect processor to be applied to the sound.

The effect processor is a callable that will be called with sound data to be processed.

Parameters
effectProcessorThe effect processor to attach to this sound, attach an empty processor to disable processing

Reimplemented from sf::SoundSource.

◆ setLooping()

void sf::SoundStream::setLooping ( bool loop)

Set whether or not the stream should loop after reaching the end.

If set, the stream will restart from beginning after reaching the end and so on, until it is stopped or setLooping(false) is called. The default looping state for streams is false.

Parameters
looptrue to play in loop, false to play once
See also
isLooping

◆ setMaxDistance()

void sf::SoundSource::setMaxDistance ( float distance)
inherited

Set the maximum distance of the sound.

The "maximum distance" of a sound is the minimum distance at which it is heard at its minimum volume. Closer than the maximum distance, it will start to fade in according to its attenuation factor. The default value of the maximum distance is the maximum value a float can represent.

Parameters
distanceNew maximum distance of the sound
See also
getMaxDistance, setAttenuation

◆ setMaxGain()

void sf::SoundSource::setMaxGain ( float gain)
inherited

Set the maximum gain of the sound.

When the sound is closer from the listener than the "minimum distance" the attenuated gain is clamped so it cannot go above the maximum gain value.

Parameters
gainNew maximum gain of the sound
See also
getMaxGain, setAttenuation

◆ setMinDistance()

void sf::SoundSource::setMinDistance ( float distance)
inherited

Set the minimum distance of the sound.

The "minimum distance" of a sound is the maximum distance at which it is heard at its maximum volume. Further than the minimum distance, it will start to fade out according to its attenuation factor. A value of 0 ("inside the head of the listener") is an invalid value and is forbidden. The default value of the minimum distance is 1.

Parameters
distanceNew minimum distance of the sound
See also
getMinDistance, setAttenuation

◆ setMinGain()

void sf::SoundSource::setMinGain ( float gain)
inherited

Set the minimum gain of the sound.

When the sound is further away from the listener than the "maximum distance" the attenuated gain is clamped so it cannot go below the minimum gain value.

Parameters
gainNew minimum gain of the sound
See also
getMinGain, setAttenuation

◆ setPan()

void sf::SoundSource::setPan ( float pan)
inherited

Set the pan of the sound.

Using panning, a mono sound can be panned between stereo channels. When the pan is set to -1, the sound is played only on the left channel, when the pan is set to +1, the sound is played only on the right channel.

Parameters
panNew pan to apply to the sound [-1, +1]
See also
getPan

◆ setPitch()

void sf::SoundSource::setPitch ( float pitch)
inherited

Set the pitch of the sound.

The pitch represents the perceived fundamental frequency of a sound; thus you can make a sound more acute or grave by changing its pitch. A side effect of changing the pitch is to modify the playing speed of the sound as well. The default value for the pitch is 1.

Parameters
pitchNew pitch to apply to the sound
See also
getPitch

◆ setPlayingOffset()

void sf::SoundStream::setPlayingOffset ( Time timeOffset)

Change the current playing position of the stream.

The playing position can be changed when the stream is either paused or playing. Changing the playing position when the stream is stopped has no effect, since playing the stream would reset its position.

Parameters
timeOffsetNew playing position, from the beginning of the stream
See also
getPlayingOffset

◆ setPosition()

void sf::SoundSource::setPosition ( const Vector3f & position)
inherited

Set the 3D position of the sound in the audio scene.

Only sounds with one channel (mono sounds) can be spatialized. The default position of a sound is (0, 0, 0).

Parameters
positionPosition of the sound in the scene
See also
getPosition

◆ setRelativeToListener()

void sf::SoundSource::setRelativeToListener ( bool relative)
inherited

Make the sound's position relative to the listener or absolute.

Making a sound relative to the listener will ensure that it will always be played the same way regardless of the position of the listener. This can be useful for non-spatialized sounds, sounds that are produced by the listener, or sounds attached to it. The default value is false (position is absolute).

Parameters
relativetrue to set the position relative, false to set it absolute
See also
isRelativeToListener

◆ setSpatializationEnabled()

void sf::SoundSource::setSpatializationEnabled ( bool enabled)
inherited

Set whether spatialization of the sound is enabled.

Spatialization is the application of various effects to simulate a sound being emitted at a virtual position in 3D space and exhibiting various physical phenomena such as directional attenuation and doppler shift.

Parameters
enabledtrue to enable spatialization, false to disable
See also
isSpatializationEnabled

◆ setVelocity()

void sf::SoundSource::setVelocity ( const Vector3f & velocity)
inherited

Set the 3D velocity of the sound in the audio scene.

The velocity is used to determine how to doppler shift the sound. Sounds moving towards the listener will be perceived to have a higher pitch and sounds moving away from the listener will be perceived to have a lower pitch.

Parameters
velocityVelocity of the sound in the scene
See also
getVelocity

◆ setVolume()

void sf::SoundSource::setVolume ( float volume)
inherited

Set the volume of the sound.

The volume is a value between 0 (mute) and 100 (full volume). The default value for the volume is 100.

Parameters
volumeVolume of the sound
See also
getVolume

◆ stop()

void sf::SoundStream::stop ( )
overridevirtual

Stop playing the audio stream.

This function stops the stream if it was playing or paused, and does nothing if it was already stopped. It also resets the playing position (unlike pause()).

See also
play, pause

Implements sf::SoundSource.


The documentation for this class was generated from the following file: