Started to work on soundfx volume

[Dajamante]

Hello Nathan,
I tested volume for sfx in the road_race example (all other examples would need to be updated at some point).
I am not sure how to proceed from here.

First and foremost, shall the sfx_queue take a Vec<Option<(sfx,vol)>> .. or Vec<(sfx,vol)>?

#[derive(Debug, Default)]
pub struct AudioManager {
    sfx_queue: Vec<(SfxPreset, f32)>,
    music_queue: Vec<Option<(MusicPreset, f32)>>,
    playing: AudioChannel,
}

Then, I wish to make both sfx_queue and music_queue as generic to play them in fn queue_managed_audio_system() but is it the right way to go?

[CleanCut]

That's very close! If you will enable the option for me to push commits to your fork, I will push up some improvements that we can take a look at. The biggest problem in the current form is that we can lose access to the music channel, which means we will not be able to stop the music.

[Dajamante]

I checked "Allow edits by maintainers" and added you as collaborator :)

[Dajamante]

Thank you!
Are there other examples left to be updated? What shall we do next?

[CleanCut]

@Dajamante I take it you approve of the changes I made. 😉 I don't think there is anything left to do for soundfx volume in this pull request, so I'll go ahead and merge it!

I listed out other stuff I'd like done for Rusty Engine 3.0 and beyond in #16, if you're interested!