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by munchbunny
3338 days ago
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I don't think OpenAL simulates some of the more complex phenomena having to do with how sound interacts with your body and ears? Valve also released an audio toolkit that does a similar thing to this one called Steam Audio. |
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It does. This blog post [0] seems to be a nice reference. What you want is called "head-related transfer function". (There are tons of papers on HRTF)
One can even turn it on for any game that use openal, even old ones. You can go download The Dark Mod now and play it with HRTF [1].
Note: am not an expert
What openal doesn't do, while this google thing does, is reverb (reflection of waves, echo). One way to do reverb is.. well simply raytrace it. Just send out a bunch of rays from the source, probably do some filtering of the results, and apply to the audio. Another way is to take a real room that you are "porting" to digital, ping somewhere in it (play the impulse response of an ideal 20kHz low pass filter, aka the sync function), then measure somewhere else. Then repeat in a.. grid or something. What you get is a bunch of filters (num_points if there is a single static "listener", or num_points^2 if there are more and or moving; as it is source->destination dependent). This can also be done by shooting rays in an arbitrary digital space, but i wanted people to imagine a room and waves going around in it. AFAIK this is how the valve bought software works.
Another thing is diffraction[2]... that idk if either gugl or volvo do. Calculate it with voxel grids then add to refraction ? Any renderers do proper Rayleigh scattering ?
[0]http://www.bitoutsidethebox.com/shabda/hrtf-info/ [1]https://www.youtube.com/watch?v=MVqFbu4gsqs [2]http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/diffrac.htm...