added Source:seek/tell

--HG--
branch : minor

src/modules/audio/openal/Source.cpp

@@ -200,6 +200,41 @@ namespace openal
 		// In case the Source isn't playing.
 		return volume;
 	}
+	
+	void Source::seek(float offset, Source::Unit unit)
+	{
+		if (valid)
+		{
+			switch (unit) {
+				case Source::UNIT_SAMPLES:
+					alSourcef(source, AL_SAMPLE_OFFSET, offset);
+					break;
+				case Source::UNIT_SECONDS:	
+				default:
+					alSourcef(source, AL_SEC_OFFSET, offset);
+					break;
+			}
+		}
+	}
+	
+	float Source::tell(Source::Unit unit) const
+	{
+		if (valid)
+		{
+			ALfloat offset;
+			switch (unit) {
+				case Source::UNIT_SAMPLES:
+					alGetSourcef(source, AL_SAMPLE_OFFSET, &offset);
+					break;
+				case Source::UNIT_SECONDS:
+				default:
+					alGetSourcef(source, AL_SEC_OFFSET, &offset);
+					break;
+			}
+			return offset;
+		}
+		return 0.0f;
+	}
 
 	void Source::setPosition(float * v)
 	{

src/modules/audio/openal/Source.h

@@ -84,6 +84,8 @@ namespace openal
 		virtual float getPitch() const;
 		virtual void setVolume(float volume);
 		virtual float getVolume() const;
+		virtual void seek(float offset, Unit unit);
+		virtual float tell(Unit unit) const;
 		virtual void setPosition(float * v);
 		virtual void getPosition(float * v) const;
 		virtual void setVelocity(float * v);