Found and fixed bug with looping 3d sounds!

Hey all, great news!

I was finally able to get ALL looping sounds (vehicles, static, you name it) to work correctly - and on every openAL dll that I had (4 different versions, including the latest one).


I found out that the looping sound wasn't played depending on where it was initially spawned. Well it DID play, but on some strange location in the middle of the map, below the ground. First I tried "fixing" that by not supplying a transformation matrix with the initial alxPlay(), but that ruined left/right balance.

What finally fixed it was a change in audio.cc, in function alxCreateSource(). Look for these lines:

// try and find an available source: 0 volume loopers get added to inactive list
   if (volume > MIN_GAIN)

...and change this to...

// try and find an available source: 0 volume loopers get added to inactive list
   if (true)

Also note that I ALWAYS call "alxUpdateMaxDistance()" in alxUpdate() because otherwise the looping samples will never reach zero volume even if you're millions of miles away, and my code of this function looks like this:

void alxUpdateMaxDistance()
{
   Point3F listener;
   alGetListener3f(AL_POSITION, &listener.x, &listener.y, &listener.z);
   for(U32 i = 0; i < mNumSources; i++)
   {
      if(mHandle[i] == NULL_AUDIOHANDLE)
         continue;
      
      LoopingList::iterator itr = mLoopingList.findImage(mHandle[i]);
      if(itr && (*itr)->mDescription.mIs3D)
      {
         Point3F pos = (*itr)->mPosition - listener;
         F32 dist = pos.magnitudeSafe();
  
         F32 min = (*itr)->mDescription.mReferenceDistance;
         F32 max = (*itr)->mDescription.mMaxDistance;
         if(dist > max)
            mSourceVolume[i] = 0.0f;
         else if(dist > min)
            mSourceVolume[i] = (*itr)->mDescription.mVolume * (min / dist);
         else
            mSourceVolume[i] = (*itr)->mDescription.mVolume;


         F32 vol = mSourceVolume[i] * mAudioTypeVolume[mType[i]] * mMasterVolume;



         alSourcef(mSource[i], AL_GAIN, vol);
       }
   }
}

Then I fixed the "stuttering" that happens on some audio cards by modifying the function "updateEngineSound" in wheeledVehicle.cc, hoverVehicle.cc and flyingVehicle.cc - Just comment out this line:

//alxSourcef(mEngineSound, AL_GAIN_LINEAR, level);

In short: do not modify the gain here, or you'll have a stuttering looping sound.



Whatcha think? Did I forget anything critical here? Does it work for you too?

BTW, I modified audio.cc to support a minimum sound distance. That way you can have different samples depending on how far away you are. That's really nice for big, distant explosions. Just tell me if you're interested ;)