Implemented API to read and seek the audio playback position of KRAudioSource

--HG--
branch : nfb

KREngine/kraken/KRAudioSource.cpp

@@ -56,6 +56,7 @@ KRAudioSource::KRAudioSource(KRScene &scene, std::string name) : KRNode(scene, n
     m_enable_obstruction = true;
     
     m_start_audio_frame = -1;
+    m_paused_audio_frame = 0;
 }
 
 KRAudioSource::~KRAudioSource()
@@ -314,12 +315,13 @@ void KRAudioSource::setRolloffFactor(float rolloff_factor)
 
 void KRAudioSource::setLooping(bool looping)
 {
+    // Enable or disable looping playback; Audio source must be stopped and re-started for loop mode changes to take effect
     m_looping = looping;
-    // Audio source must be stopped and re-started for loop mode changes to take effect
 }
 
 bool KRAudioSource::getLooping()
 {
+    // Returns true if the playback will automatically loop
     return m_looping;
 }
 
@@ -400,8 +402,15 @@ void KRAudioSource::physicsUpdate(float deltaTime)
 
 void KRAudioSource::play()
 {
+    // Start playback of audio at the current audio sample position.  If audio is already playing, this has no effect.
+    // play() does not automatically seek to the beginning of the sample.  Call setAudioFrame( 0 ) first if you wish the playback to begin at the start of the audio sample.
+    // If not set to looping, audio playback ends automatically at the end of the sample
+    
+    if(!m_playing) {
         KRAudioManager *audioManager = getContext().getAudioManager();
-    m_start_audio_frame = audioManager->getAudioFrame();
+        assert(m_start_audio_frame == -1);
+        m_start_audio_frame = audioManager->getAudioFrame() - m_paused_audio_frame;
+        m_paused_audio_frame = -1;
         audioManager->activateAudioSource(this);
         if(audioManager->getAudioEngine() == KRAudioManager::KRAKEN_AUDIO_OPENAL) {
             getContext().getAudioManager()->makeCurrentContext();
@@ -420,18 +429,27 @@ void KRAudioSource::play()
             }
             ALDEBUG(alSourcePlay(m_sourceID));
         }
+    }
     m_playing = true;
 }
 
 void KRAudioSource::stop()
 {
+    // Stop playback of audio.  If audio is already stopped, this has no effect.
+    // If play() is called afterwards, playback will continue at the current audio sample position.
+    
+    if(m_playing) {
+        m_paused_audio_frame = getAudioFrame();
         m_start_audio_frame = -1;
         m_playing = false;
         getContext().getAudioManager()->deactivateAudioSource(this);
     }
+}
 
 bool KRAudioSource::isPlaying()
 {
+    // Returns true if audio is playing.  Will return false if a non-looped playback has reached the end of the audio sample.
+    
     return m_playing;
 }
 
@@ -504,16 +522,46 @@ int KRAudioSource::getBufferFrame()
     return m_currentBufferFrame;
 }
 
-__int64_t KRAudioSource::getStartAudioFrame()
+__int64_t KRAudioSource::getAudioFrame()
 {
-    return m_start_audio_frame;
+    // Returns the audio playback position in units of integer audio frames.
+    
+    if(m_playing) {
+        return getContext().getAudioManager()->getAudioFrame() - m_start_audio_frame;
+    } else {
+        return m_paused_audio_frame;
+    }
+}
+
+void KRAudioSource::setAudioFrame(__int64_t next_frame)
+{
+    // Sets the audio playback position with units of integer audio frames.
+    if(m_playing) {
+        m_start_audio_frame = getContext().getAudioManager()->getAudioFrame() - next_frame;
+    } else {
+        m_paused_audio_frame = next_frame;
+    }
+}
+
+
+float KRAudioSource::getAudioTime()
+{
+    // Gets the audio playback position with units of floating point seconds.
+    
+    return getAudioFrame() / 44100.0f;
+}
+
+void KRAudioSource::setAudioTime(float new_position)
+{
+    // Sets the audio playback position with units of floating point seconds.
+    setAudioFrame(new_position * 44100.0f);
 }
 
 void KRAudioSource::sample(int frame_count, int channel, float *buffer, float gain)
 {
     KRAudioSample *source_sample = getAudioSample();
     if(source_sample && m_playing) {
-        __int64_t next_frame = getContext().getAudioManager()->getAudioFrame() - getStartAudioFrame();
+        __int64_t next_frame = getAudioFrame();
         source_sample->sample(next_frame, frame_count, channel, buffer, gain, m_looping);
         if(!m_looping && next_frame > source_sample->getFrameCount()) {
             stop();

KREngine/kraken/KRAudioSource.h

@@ -51,10 +51,41 @@ public:
     virtual void physicsUpdate(float deltaTime);
     
     void render(KRCamera *pCamera, std::vector<KRPointLight *> &point_lights, std::vector<KRDirectionalLight *> &directional_lights, std::vector<KRSpotLight *>&spot_lights, const KRViewport &viewport, KRNode::RenderPass renderPass);
+
+    // ---- Audio Playback Controls ----
+    
+    // Start playback of audio at the current audio sample position.  If audio is already playing, this has no effect.
+    // play() does not automatically seek to the beginning of the sample.  Call setAudioFrame( 0 ) first if you wish the playback to begin at the start of the audio sample.
+    // If not set to looping, audio playback ends automatically at the end of the sample
     void play();
+    
+    // Stop playback of audio.  If audio is already stopped, this has no effect.
+    // If play() is called afterwards, playback will continue at the current audio sample position.
     void stop();
+    
+    // Returns true if audio is playing.  Will return false if a non-looped playback has reached the end of the audio sample.
     bool isPlaying();
     
+    // Returns the audio playback position in units of integer audio frames.
+    __int64_t getAudioFrame();
+    
+    // Sets the audio playback position with units of integer audio frames.
+    void setAudioFrame(__int64_t next_frame);
+    
+    // Gets the audio playback position with units of floating point seconds.
+    float getAudioTime();
+    
+    // Sets the audio playback position with units of floating point seconds.
+    void setAudioTime(float new_position);
+    
+    // Returns true if the playback will automatically loop
+    bool getLooping();
+    
+    // Enable or disable looping playback; Audio source must be stopped and re-started for loop mode changes to take effect
+    void setLooping(bool looping);
+    
+    // ---- End: Audio Playback Controls ----
+    
     void setSample(const std::string &sound_name);
     std::string getSample();
     
@@ -66,8 +97,7 @@ public:
     float getPitch();
     void setPitch(float pitch);
     
-    bool getLooping();
+
-    void setLooping(bool looping);
     
     bool getIs3D();
     void setIs3D(bool is3D);
@@ -94,12 +124,11 @@ public:
     KRAudioBuffer *getBuffer();
     int getBufferFrame();
     
-    
-    __int64_t getStartAudioFrame();
     void sample(int frame_count, int channel, float *buffer, float gain);
     
 private:
-    __int64_t m_start_audio_frame; // Global audio frame that matches the start of the audio sample playback
+    __int64_t m_start_audio_frame; // Global audio frame that matches the start of the audio sample playback; when paused or not playing, this contains a value of -1
+    __int64_t m_paused_audio_frame; // When paused or not playing, this contains the local audio frame number.  When playing, this contains a value of -1
     int m_currentBufferFrame; // Siren Audio Engine frame number within current buffer
     void advanceBuffer();