[Openal-devel] Loopback API design question

[Chris Robinson]

On Sunday, March 04, 2012 11:08:36 AM Erik Hofman wrote:
> This triggered the thought that we might need loopback device
> enumeration using ALC_ALL_LOOPBACK_DEVICES_SPECIFIER in case we should
> proceed with the capture_loopback extension.

If the capture functions are capturing "live" playback, then I don't think a 
separate enumeration is needed since you're working with actual playback 
devices. ALC_DEVICE_SPECIFIER or ALC_ALL_DEVICES_SPECIFIER would be adequate 
to look for devices that the app can then check for the extension on.

Capturing could be enabled via a context creation attribute (that, like 
ALC_FREQUENCY and such, affects the whole device from that point on). An app 
would be able to query for the extension, then supply an attribute list 
containing { ALC_CAPTURE_LOOPBACK, ALC_TRUE } ... along with something to 
specify a format. The app would then query ALC_CAPTURE_LOOPBACK with 
alcGetIntegerv to make sure it's actually enabled (ie, is still ALC_TRUE), 
then the capture functions could be used with the device to check for and 
retrieve rendered audio.