Audio::OpenALRenderableStreamingSource Class Reference

#include <OpenALRenderableStreamingSource.h>

Inheritance diagram for Audio::OpenALRenderableStreamingSource:

Public Member Functions
	OpenALRenderableStreamingSource (Source *source)
virtual	~OpenALRenderableStreamingSource ()
bool	shouldBePlaying () const
Public Member Functions inherited from Audio::RenderableSource
virtual	~RenderableSource ()
void	startPlaying (Timestamp start=0) throw (Exception)
void	stopPlaying () throw ()
bool	isPlaying () const throw ()
Timestamp	getPlayingTime () const throw (Exception)
Source *	getSource () const throw ()
void	seek (Timestamp time) throw (Exception)
void	update (int flags, const Listener &sceneListener) throw ()
Public Member Functions inherited from Audio::UserData
virtual	~UserData ()

Protected Member Functions
virtual void	startPlayingImpl (Timestamp start) throw (Exception)
virtual void	stopPlayingImpl () throw (Exception)
virtual bool	isPlayingImpl () const throw (Exception)
virtual Timestamp	getPlayingTimeImpl () const throw (Exception)
virtual void	updateImpl (int flags, const Listener &sceneListener) throw (Exception)
virtual void	seekImpl (Timestamp time) throw (Exception)
ALuint	getALSource () const
void	queueALBuffers () throw (Exception)
Protected Member Functions inherited from Audio::RenderableSource
	RenderableSource (Source *source) throw ()

Additional Inherited Members
Public Types inherited from Audio::RenderableSource
enum	UpdateFlags {   UPDATE_ALL = 0x0F, UPDATE_LOCATION = 0x01, UPDATE_ATTRIBUTES = 0x02, UPDATE_EFFECTS = 0x04,   UPDATE_GAIN = 0x08 }

Detailed Description

OpenAL Renderable Source class

Remarks

This class implements the RenderableSource interface for the OpenAL renderer.

Definition at line 23 of file OpenALRenderableStreamingSource.h.

Constructor & Destructor Documentation

Audio::OpenALRenderableStreamingSource::OpenALRenderableStreamingSource

(

Source *

source)

Definition at line 28 of file OpenALRenderableStreamingSource.cpp.

        : RenderableSource(source)
        , alSource(0)
        , atEos(false)
        , shouldPlay(false)
        , buffering(false)
    {
        alGenSources(1,&alSource);
    }

Audio::OpenALRenderableStreamingSource::~OpenALRenderableStreamingSource ( )

virtual

Definition at line 38 of file OpenALRenderableStreamingSource.cpp.

    {
        alDeleteSources(1,&alSource);
    }

Member Function Documentation

ALuint Audio::OpenALRenderableStreamingSource::getALSource ( ) const

inlineprotected

Derived classes may use the underlying AL source handle to set additional attributes

Definition at line 63 of file OpenALRenderableStreamingSource.h.

Referenced by getPlayingTimeImpl(), isPlayingImpl(), and queueALBuffers().

{ return alSource; }

Timestamp Audio::OpenALRenderableStreamingSource::getPlayingTimeImpl ( ) const throw ( Exception )

protectedvirtual

See Also

RenderableSource::getPlayingTimeImpl.

Implements Audio::RenderableSource.

Definition at line 88 of file OpenALRenderableStreamingSource.cpp.

References AL_SEC_OFFSET, f, getALSource(), Audio::Source::getSound(), and Audio::RenderableSource::getSource().

    {
        ALfloat offs = -1.f;
        alGetSourcef(getALSource(), AL_SEC_OFFSET, &offs);
        
        if (offs < 0.f)
            throw NotImplementedException("getPlayingTimeImpl");
        
        Timestamp base = dynamic_cast<OpenALStreamingSound*>(getSource()->getSound().get())
            ->getTimeBase();
        
        return Timestamp(offs) + base;
    }

bool Audio::OpenALRenderableStreamingSource::isPlayingImpl ( ) const throw ( Exception )

protectedvirtual

See Also

RenderableSource::isPlayingImpl.

Implements Audio::RenderableSource.

Definition at line 80 of file OpenALRenderableStreamingSource.cpp.

References getALSource().

    {
        ALint state = 0;
        alGetSourcei(getALSource(), AL_SOURCE_STATE, &state);
        return (state == AL_PLAYING);
    }

void Audio::OpenALRenderableStreamingSource::queueALBuffers ( ) throw ( Exception )

protected

Queue AL buffers from the source's AL sound stream.

Note

It will fail with an assertion if the attached sound isn't a streaming OpenAL sound

It will not throw an EndOfStream exception, even if the sound reaches the end and it's not a looping source.

Definition at line 193 of file OpenALRenderableStreamingSource.cpp.

References AL_NULL_BUFFER, buffer, e, fprintf, getALSource(), Audio::Source::getSound(), Audio::RenderableSource::getSource(), i, Audio::Source::isLooping(), Audio::OpenALStreamingSound::readAndFlip(), Audio::OpenALStreamingSound::seek(), and Audio::OpenALStreamingSound::unqueueBuffer().

    {
        SharedPtr<Sound> sound = getSource()->getSound();
        
        if (!sound->isLoaded())
            sound->load();
        
        assert(sound->isStreaming() && "OpenALRenderableStreamingSource can only handle streaming sounds");

        buffering = true;
        
        OpenALStreamingSound *streamingSound = dynamic_cast<OpenALStreamingSound*>(sound.get());
        Source *source = getSource();
        ALSourceHandle als = getALSource();
        ALint buffersProcessed = 0;
        
        // Unqueue any buffers the AL is done with, 
        // returning them to the streaming sound
        alGetSourcei(als, AL_BUFFERS_PROCESSED, &buffersProcessed);
        
        while (buffersProcessed > 0) {
            ALBufferHandle buffers[2];
            ALsizei nbuffers = (buffersProcessed > 2) ? 2 : (ALsizei)buffersProcessed;
            alSourceUnqueueBuffers(als, nbuffers, buffers);
            
            for (ALsizei i=0; i<nbuffers; ++i)
                streamingSound->unqueueBuffer(buffers[i]);
            
            buffersProcessed -= nbuffers;
        }
        
        // Get buffers from the streaming sound and queue them 
        // until the streaming sound says Basta!
        ALBufferHandle buffer;
        do {
            try {
                buffer = streamingSound->readAndFlip();
            } catch(EndOfStreamException e) {
                fprintf(stderr, "EOS!\n");
                if (source->isLooping()) {
                    streamingSound->seek(0);
                    buffer = streamingSound->readAndFlip();
                } else {
                    atEos = true;
                    buffer = AL_NULL_BUFFER;
                }
            }
            if (buffer != AL_NULL_BUFFER)
                alSourceQueueBuffers(als, 1, &buffer);
        } while (buffer != AL_NULL_BUFFER);
    }

void Audio::OpenALRenderableStreamingSource::seekImpl ( Timestamp  time) throw ( Exception )

protectedvirtual

See Also

RenderableSource::seekImpl.

Implements Audio::RenderableSource.

Definition at line 103 of file OpenALRenderableStreamingSource.cpp.

    {
        // Seek the stream to the specified position
        atEos = false;
        dynamic_cast<OpenALStreamingSound*>(getSource()->getSound().get())
            ->seek(time);
    }

bool Audio::OpenALRenderableStreamingSource::shouldBePlaying ( ) const

inline

Returns whether this stream should be playing

Remarks

Streaming sources may halt due to buffer underruns. By keeping track of the desired state, rather than querying the underlying AL source, we can overcome this problem.

Definition at line 41 of file OpenALRenderableStreamingSource.h.

{ return shouldPlay && !atEos; }

void Audio::OpenALRenderableStreamingSource::startPlayingImpl ( Timestamp  start) throw ( Exception )

protectedvirtual

See Also

RenderableSource::startPlayingImpl.

Implements Audio::RenderableSource.

Definition at line 43 of file OpenALRenderableStreamingSource.cpp.

References checkAlError, clearAlError, and start.

    {
        if (!isPlayingImpl()) {
            SharedPtr<Sound> sound = getSource()->getSound();
            
            assert(sound->isStreaming() && "OpenALRenderableStreamingSource can only handle streaming sounds");
            
            if (!sound->isLoaded())
                sound->load();
            else if (!buffering)
                dynamic_cast<OpenALStreamingSound*>(sound.get())->flushBuffers();
            
            // Seek the stream to the specified position
            atEos = false;
            shouldPlay = true;
            dynamic_cast<OpenALStreamingSound*>(sound.get())->seek(start);
            
            // Make sure we have some starting buffers queued
            queueALBuffers();
            
            // Tell the AL to start playing
            clearAlError();
            ALuint als = getALSource();
            alSourcePlay(als);
            checkAlError();
        }
    }

void Audio::OpenALRenderableStreamingSource::stopPlayingImpl ( ) throw ( Exception )

protectedvirtual

See Also

RenderableSource::stopPlayingImpl.

Implements Audio::RenderableSource.

Definition at line 72 of file OpenALRenderableStreamingSource.cpp.

    {
        shouldPlay = false;
        buffering = false;
        alSourceStop(alSource);
    }

void Audio::OpenALRenderableStreamingSource::updateImpl ( int  flags, const Listener &  sceneListener  ) throw ( Exception )

protectedvirtual

See Also

RenderableSource::updateImpl.

Implements Audio::RenderableSource.

Definition at line 112 of file OpenALRenderableStreamingSource.cpp.

References Audio::alSource3f(), checkAlError, clearAlError, f, Audio::Source::getAngleRange(), Audio::Source::getDirection(), Audio::Source::getGain(), Audio::Source::getPosition(), Audio::Source::getRadius(), Audio::Source::getSound(), Audio::Source::getVelocity(), Audio::Source::isAttenuated(), Audio::Source::isLooping(), Audio::Source::isRelative(), M_1_PI, Audio::Range< T >::max, and Audio::Range< T >::min.

    {
        Source *source = getSource();
        ALSourceHandle als = getALSource();
        
        // Restart playing in case of a buffer underrun,
        // else just fill buffers
        if (shouldBePlaying() && !isPlayingImpl()) {
            // startPlayingImpl(source->getWouldbePlayingTime());
            // NOTE: Cannot use startPlaying because it stresses the buggy seek method
            //  Must fix that
            
            SharedPtr<Sound> sound = source->getSound();
            
            if (!sound->isLoaded())
                sound->load();
            else if (!buffering)
                dynamic_cast<OpenALStreamingSound*>(sound.get())->flushBuffers();
            
            // Make sure we have some starting buffers queued
            queueALBuffers();
            
            // Tell the AL to start playing
            clearAlError();
            ALuint als = getALSource();
            alSourcePlay(als);
            checkAlError();
        } else {
            queueALBuffers();
        }
        
        // Update various attributes if required
        clearAlError();
        
        if (flags & UPDATE_ATTRIBUTES) {
            // Distance attenuation
            if (source->isAttenuated()) {
                alSourcef(als, AL_REFERENCE_DISTANCE, source->getRadius());
                alSourcef(als, AL_ROLLOFF_FACTOR, 1.f / source->getRadius());
            } else {
                alSourcef(als, AL_ROLLOFF_FACTOR, 0.f);
            }
            // Cone
            {
                Range<Scalar> angleRange = source->getAngleRange();
                alSourcef(als, AL_CONE_INNER_ANGLE, float(angleRange.min) * M_1_PI * 360.f);
                alSourcef(als, AL_CONE_OUTER_ANGLE, float(angleRange.max) * M_1_PI * 360.f);
                alSourcef(als, AL_CONE_OUTER_GAIN , 0.f);
            }
            // Relativity
            alSourcei(als, AL_SOURCE_RELATIVE, source->isRelative() ? AL_TRUE : AL_FALSE);
            // Looping
            alSourcei(als, AL_LOOPING, source->isLooping() ? AL_TRUE : AL_FALSE);
        }
        if (flags & UPDATE_GAIN) {
            // Gain
            alSourcef(als, AL_GAIN, source->getGain());
        }
        if (flags & UPDATE_LOCATION) {
            if (source->isRelative()) {
                alSource3f(als, AL_POSITION, source->getPosition());
                alSource3f(als, AL_VELOCITY, source->getVelocity());
                alSource3f(als, AL_DIRECTION, source->getDirection());
            } else {
                alSource3f(als, AL_POSITION, 
                    source->getPosition() - sceneListener.getPosition() );
                alSource3f(als, AL_VELOCITY, 
                    sceneListener.toLocalDirection(
                        source->getVelocity() - sceneListener.getVelocity()
                    ) );
                alSource3f(als, AL_DIRECTION, 
                    sceneListener.toLocalDirection(
                        source->getDirection()
                    ) );
            }
        }
        
        checkAlError();
    }

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

• src/audio/renderers/OpenAL/OpenALRenderableStreamingSource.h
• src/audio/renderers/OpenAL/OpenALRenderableStreamingSource.cpp