[Openal] Mute when switch windows

[Dave Shillito]

Ah... That would explain it, I was not even aware DSBCAPS_GLOBALFOCUS exited - so had obviously not used it :o)

I actually like that the sound continues (after all the graphics don't stop do they), but everyone else on the team would rather hear their mp3's. :o(

Thanks for the quick response,

DAve

-----Original Message-----
From: Daniel PEACOCK [mailto:dpeacock at creativelabs.com] 
Sent: 18 July 2007 18:25
To: Dave Shillito
Cc: openal at opensource.creative.com
Subject: Re: [Openal] Mute when switch windows

Hi Dave,

I think the behaviour in DSound that enables / disables a particular DSBuffer to be heard when the application / window loses focus is the DSBCAPS_GLOBALFOCUS flag which is part of the DSBUFFERDESC structure passed to the CreateSoundBuffer function.

In OpenAL the Sources will continue to play and be audible regardless of the whether the application has the "focus" or not. The solution we recommend is to trap the WM_ACTIVATE message in your application (sent when ever your application gains or loses the "focus") and either set the Listener Gain to 0 (to mute all the Sources but allow them to continue to play) or call alSourcePause on each Source. In the later case, your application will need to know not to start any new sounds while it does not have the focus.

Dan

Daniel Peacock
Custom Engineering Manager
Creative Labs, Inc. 
email : dpeacock at creativelabs.com 
phone : (408) 546 6552

Hi All, 

I have just switched our app over from DirectSound to OpenAL.

In the DirectSound version of the app when we run windowed and switch
focus to a new window our sound would be muted.  Now in the OpenAL
version the sound continues.  

I think this was since I used "SetCooperativeLevel(hwnd,
DSSCL_PRIORITY)" in DirectSound.

Is it possible to recreate the DirectSound behaviour in OpenAL?

I was looking at alcSuspendContext & alcProcessContext, but was unclear
as to what would happen if the app continued to run - triggering sounds
in the background.  

Cheers,

DAve






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