Hi Robert, > I "was" to develop osgAudio I would use osgAL/OpenAL as a template, > much in the same way as you seem to be look at the topic. I'd also > see how SDL audio might map as this has cross platform audio support > that might be reasonable implementation for non spaitialized sound.
And maybe we should have a look to some other libs too, such as SFML ( http://www.sfml-dev.org )? > I would also try to keep things decoupled so items like a Manager > would be something that is implementation dependent, rather that > something that end user need worry about. Sorry I don't understand. Do you mean you're in favor of my second idea (having a kind of priorirty for sounds that the plugin would use to automatically turn on/off sounds to fit the limitation of the number of sources)? > I would have thought that > one might be able to capture the camera position relative to > listener/sound sources by using the existing cull traversal as the way > to extract the required info to pass on to OpenAL. Threading and > multiple camera traversals might throw this a bit though... so > perhaps a standard alone audio traversal would be appropriate as one > would only have one audio "context". Perhaps the ideal would be to > allow the viewer to run an audio thread that runs in parallel with the > cull/draw traversal threads. Having a separate thread sounds fine to me. CPU is not used enough for audio! Maybe a good occlusion computation would add immersion; so I think a separate thread is better. Should there be audio update and cull/"render" traverals for the viewer then? > I am overloaded with my existing work so I can't take on any of this > work myself, I'll happy cheer on from the side lines though. I > certainly want to see an osgAudio merged into the core OSG. Perhaps a > feature for OSG-2.10. > > Robert. I'm also too busy to work on osgAudio, but I'd like to help as much as I can. Sukender PVLE - Lightweight cross-platform game engine - http://pvle.sourceforge.net/ > On Thu, Nov 27, 2008 at 1:37 PM, Sukender <[EMAIL PROTECTED]> wrote: >> Hi Robert, hi everyone, >> >> I totally agree that we need an abstraction layer and plugins. So let's say >> "osgAudio" is that abstraction layer, and that "osgAL" is a future plugin >> based on the current osgAL work. >> - What would be in the osgAudio then? >> - Should we (and how could we do to) leave a degree of freedom to plugins so >> that users can access specific features (= not handled in osgAudio)? >> >> I guess osgAudio has to be very simple. Here are some of my ideas: >> - As LightSources, there should be AudioSources nodes that we can position >> somewhere. >> - AudioSource may be absolute (= heard everywhere = no distance attenuation >> = no culling). >> - AudioSource should be attached to a Sound (= AudioData = buffer or stream >> + some parameters like doppler factor, gain, velocity...) >> - Sound should be able to read many formats/codecs (PCM, Vorbis...) >> - There should be a cache for sounds (for buffers but not for streams I >> guess!) >> - The user may update the Sounds parameters on update traversal (mainly for >> the velocity - For me, the physics will drive this value) >> - There should be Listeners, and the main Listener should be by default >> linked with the main camera (Is that easy to do?) >> - Sounds may be occuled, but I wonder if it's better to add occulder >> "geometries" in the world, or set a specific flag on existing geometries to >> say they occult sounds. >> Well this looks much like osgAL, but that's normal! However, I'd like to >> remove the presence of the osgAL manager if possible. >> >> About allocation/deallocation of internal sound buffers, I have two ideas: >> 1. As for lights, the user is limited to a given number and he has to >> manually switch on/off those (s)he wants. >> 2. This not be the matter of the user. Eventually (s)he could set their >> number, but not much more. The sources are given a base priority, which can >> be lowered if the sound is attenuated (= if listener is far). The 'n' most >> important AudioSources would then be active and the other inactive. >> Eventually, a parameter would have to say if AudioSources may or may not be >> stopped suring playing to leave another one play (= a more imporant one). >> >> Which one do you prefer? The second idea looks a little bit like the >> LightSourcesManager I wrote (that switch on the 8 most important lights), >> and that can easily be generalized. The advantage is simplicity for the >> user, and the drawback is that we then cannot remove the "osgAL manager" I >> told before. >> >> I hope this will help to see an osgAudio soon! >> >> Sukender >> PVLE - Lightweight cross-platform game engine - http://pvle.sourceforge.net/ >> >> >> Le Thu, 27 Nov 2008 11:17:01 +0100, Robert Osfield <[EMAIL PROTECTED]> a >> écrit: >> >>> Hi Sukender, >>> >>> Previously I have looked at merging osgAL into svn/trunk, but on >>> review of the code decided that a straight merge was inappropriate. >>> For end user build simplicity OpenAL++ and osgAL would be best merged. >>> >>> The structure of an audio library for the core OSG are something I >>> feel need abstraction from any specific audio implementation. So in >>> my ideal world an osgAudio library would provide the basic glue for >>> adding audio into the scene graph, and the base classes that provide >>> the hooks into the implementations, then implementations would be >>> provided via plugins. No such library currently exists so it'd have >>> to be written. The need for abstraction is required to ensure that >>> future portability to embedded platforms isn't hampered by large extra >>> dependencies. >>> >>> Robert. >>> >>> On Wed, Nov 26, 2008 at 10:40 PM, Sukender <[EMAIL PROTECTED]> wrote: >>>> Hi all, >>>> >>>> I'd like to know who's interested in audio for OSG: >>>> - Who would like to use it? >>>> - Who would like to see some osgAudio included in OSG? >>>> - Who would like to develop such a thing? >>>> >>>> Well, actually I use osgAL, that depends on OpenAL and OpenAL++ (and Ogg >>>> and Vorbis if needed). It can do interesting things, including spatialized >>>> audio. >>>> I'd really like to see osgAL included in OSG but its author is not that >>>> active (he told me!) and I guess there is some work to be done before >>>> this. And to begin, the CMake build system for it (Compiling it was not >>>> that easy). >>>> >>>> But I also have to say that compiling OpenAL under Win32 was a PAIN (much >>>> more than osgAL), because I could not find TWO IDENTICAL libs that were >>>> structured the same way. I finally compiled from >>>> svn://connect.creativelabs.com/OpenAL/trunk, and I had to tweak the >>>> project files to fit my needs: >>>> - Added 'd' as debug suffix. >>>> - Added Win32 libs (because I'm using an Express version of VC). >>>> - Manually deployed the binaries by copying them at the right spot. >>>> Moreover, OpenAL needs DirectSound under Windows (!!!), so I also needed >>>> the DirectX SDK... >>>> >>>> If someone is ready to cleanup/structure/merge into OSG... PLEASE DO IT! :) >>>> >>>> Also feel free to tell anything interesting about audio in OSG. Maybe are >>>> there interesting cross-platforms and open-source libs? Thread's started! >>>> >>>> Sukender >>>> PVLE - Lightweight cross-platform game engine - >>>> http://pvle.sourceforge.net/ >>>> _______________________________________________ >>>> osg-users mailing list >>>> [email protected] >>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
