Add ability to pan audio stream player audio left-right and front/back

[rossunger]

AudioStreamPlayer now has a Vector2 property that controls the panning of the sound which works with stereo and surround.

[Calinou]

See also a previous implementation of the same feature: #51667

[rossunger]

See also a previous implementation of the same feature: #51667

Interesting. My pr also supports front-back panning for surround sound, and works with the current AudioStreamPlayer's way of dealing with surround .

It seemed Iike the other pr got closed without merging but from the comments I didnt understand what the outcome was / why.

I think there is a good use case for this to be part of AudioStreamPlayer specifically (not the 2d or 3d one).

If you know of any other place where there was a discussion about why this feature should not exist please let me know (I didn't notice any other links in the other pr you mentioned before). I seem to have mixed luck with finding existing PRs/proposals ..
even though I search the GitHub I've repeatedly missed existing things.

[rossunger]

Also looking through the source of that other pr I found improvements I need to make to my pr for preserving loudness!