[Openal] Volume Levels on Win32/Linux

[andyb at binarybydesign.net]

Hi all,

I'm currently working on a multiplatform engine which has recently moved to
using OpenAL for all sound effect playback as well as to providing a channel
for any digital music (e.g OGG Vorbis or software synth'd MIDI). The testing
that has been done for this has been on Linux and all worked fine. However the
Win32 version of the engine seems to play all samples at a considerably lower
volume (Our original assumption was the default listener gain was 0.5, but it
appears to be 1.0 on both platforms). We are setting MIN/MAX GAIN, REFERENCE
DISTANCE, ROLLOFF FACTOR and GAIN on all sources, The distance model is
explicitly set to AL_INVERSE_DISTANCE. The listener POSITION, VELOCITY and
ORIENTATION are also explicitly set.

The sound device we are using tends to be DirectSound (although the engine
doesn't pick the device specifically) and the OpenAL DLL's are sourced from the
latest installer from Creative (1.2.8 I think).

I'm fairly certain that the code is giving the same values to OpenAL for each
platform, but conceed I have not checked everything yet. However is there
anything obvious (e.g. the windows code sets the wave mixer to 50%) that may
account for this?

                                                                                
                                             For the curious, further links:-

Forum discussion on OpenAL issue:
http://sourceforge.net/forum/forum.php?thread_id=1232240&forum_id=6482

Bug report on SF:
http://sourceforge.net/tracker/index.php?func=detail&aid=1150897&group_id=2232&atid=102232

Project website:
http://edge.sf.net

Source tree plus main OpenAL source file:
http://cvs.sourceforge.net/viewcvs.py/edge/edge/AL/i_sound.cpp?view=markup
http://cvs.sourceforge.net/viewcvs.py/edge/edge/

Thanks in advance,

--
Andrew Baker


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