Revamp the sound engine.

[TheRamenChef]

The main feature of this pull request is a total rewrite of the SoundPlayback implementation. Notable changes include:

• A resource leak in the previous implementation has been fixed (every time a sound looped, it would open a new line without closing the previous one).
• There is now a Track interface for more complex music, such as music with an intro.
• There is no longer an audible seam between looping sounds, as the data line is reused.

Also included is an implementation of layer opacity that I had previously forgotten to write.

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This is currently marked as a draft pull request as there is a major bug in my implementation that makes some sounds not play. It's extremely annoying, as it's highly intermittent and I've been unable to determine the cause. It is assigned a thread, but for some reason the task exits before it can write any data to the line, but it's not being cancelled, because if it was, it would hit a breakpoint. You have implemented a sound playback before; what am I doing wrong?

[steffen-wilke]

Just as a first note: The SoundEngine is designed to be accessed via Game.audio(). Regardless of the functional changes in this PR, this will stay the same. Not just for the SoundEngine but also for all the other major components of the engine.

[TheRamenChef]

I've never really asked this before, but why are all these components singletons, instead of static classes?

[steffen-wilke]

It's a design decision we've made. The main benefit is that the Game class exposes all the API of the engine. This way, the developer doesn't have to remember the name of all the static classes but instead can just type in Game. and intellisense will figure out all the options.

[steffen-wilke]

I've cherry-picked the general commits fc6b586 and cb663c1 and will now proceed with getting the actual SoundEngine changes into the master branch

[TheRamenChef]

Keep in mind that this implementation has a major bug in it which is why this is only a draft pull request. I assigned you in the hopes that you would be able to fix it.

[steffen-wilke]

@TheRamenChef Thank's for the hint, I've just started to play around with the implementation and it also seems like the sound volume is not applied to the sound playbacks anymore. I'm currently not sure if this should be merged to the master before 0.4.16. I think this needs some more time for investigation and to mature.

[TheRamenChef]

The volume isn't dB gain; it's an actual multiplier on the amplitude of the sound wave. You should get a noticeable response from setting it to 0.1 or such.

[TheRamenChef]

I've managed to fix the issue, whatever it was. This pull request is now live.

If you want to undo the sound engine being made static, go ahead.

[steffen-wilke]

Perfect, will do so this weekend.

[steffen-wilke]

The volume isn't dB gain; it's an actual multiplier on the amplitude of the sound wave. You should get a noticeable response from setting it to 0.1 or such.

I just set it to a minimum in the settings but this doesn't have any influence and the sounds are still played at normal volume.

The music volume is evaluated properly it seems.

[TheRamenChef]

Oh, you were talking about the sound volume in the settings. I just forgot to implement that. I've done that now.

[TheRamenChef]

It's working now; the Travis CI build seems to have the same problem as my early pull requests.

[steffen-wilke]

It's working now; the Travis CI build seems to have the same problem as my early pull requests.

I think the breaking CI on the branch was due to some changes I recently made to the Travis configuration that were not merged to the branch. So the actual build succeeded but the SonarQube part failed.