Flaky android sound fix

[roponator]

TLDR: there is an issue when calling C++ functions from C# which have float parameters passed by value: the parameters in the function signature after the float parameters are corrupted. I'm totaly out of ideas, I have not tried compiling mono/xamarin, but it seems as if there is an issues in the C# -> C++ interop layer.
Therefore if a function has more than one float parameters or has a parameter after the float parameter it will get corrupted. The funny thing is that if paramters are of type int it works 100% correctly.

In practice this causes sounds to not be played, because calls like AL.Source that set position (which accepts 3 floats) pass two of the three floats corrupted (their values become like 5*10^38)

This branch is a workaround around the issue as it passes multiple float parameters by reference(pointers).

This fix could be considered totaly "legit" if all functions with float params (even those with just a single float param) would be passed by reference, and not just those with multiple float params, but this seems to cause no issues in practice.

I wrote a detailed issue report on stack overflow and on git:
http://stackoverflow.com/questions/42028853
MonoGame/MonoGame#5443

[dellis1972]

@roponator It think this line needs to be uncommented again.

[roponator]

@dellis1972 If I uncomment this I get this error when compiling:

Severity	Code	Description	Project	File	Line	Suppression State
Error		java.lang.IllegalArgumentException: already added :  Lopentk_1_0/GameViewBase;	MonoGameAndroidAudioTest			

I've done the same in AndroidGameView.cs.

I haven't worked with this 'Register' stuff until now so I'm not sure what's up with it. Could it be some other change which cause it to be reigstered already?

[roponator]

It seems this is a know problem:
1feb376

Not sure if it's safe to change 1.0 to 1.1 though. Any thoughts?

[dellis1972]

@roponator when debugging the code locally you need to change it to

Register ("opentk_1_0/GameViewBase1")

This is because of the code generator. Its just a side effect of trying to debug. When a release is done (i.e. when we ship OpenTK with the android product) those attributes need to be in place.

[roponator]

@dellis1972 ok, thx for explaining.

Reverted those files.

[roponator]

@dellis1972 Hey, you said you work on Xamarin.Android and that you could get someone to take a quick look at this, could you please poke someone so we know if the problem is in Xamarin.Android or somewhere else.

[dellis1972]

@radekdoulik are you able to review this issue/change?

[roponator]

@dellis1972 @radekdoulik
bump, this thing is still a total mystery, did the xamarin team every experienced anything like it?