[Openal-devel] Quick Clarifications

[Christopher Fitzgerald]

Greetings,

> 1.  The Room Roll-off applies when the receiving FX Slot is "Environmental" in
> EAX terminology, or has the AL_EFFECTSLOT_AUXILIARY_SEND_AUTO flag enabled
> in EFX terminology. If the FX Slot contains a Reverb then the Room
> Roll-off used in the calculations is the sum of the source and reverb's
> Room Roll Factors, if the FX slot does not contain a reverb then the Room
> RollOff used in the calculations is just the Source Room RollOff Factor.

Ah good.  I wanted to be 100% sure since the EFX specification relates the source room roll-off to the "reflected sound (early reflections and reverberation)" which is clearly reverb-centric.

> 2. Source Gain clamping (AL_MIN_GAIN and AL_MAX_GAIN properties) should occur
> after distance and cone attentuation, and (Source) gain (see AL Spec
> Section 3.5). It should be done before Listener Gain is applied (which
> acts like a master volume control).

That's how I read it.

> However, Chris is right ... it seems that the Generic Software or Generic
> Hardware devices are not doing cone attenuation before source gain
> clamping.

Which is where the confusion was coming from.

> 3. The EFX Filter Gain is applied after clamping. I guess you could argue
> that this is a source-related attenuation and perhaps should be performed
> before clamping - but because it is a frequency dependant attenuation it
> doesn't really fit in with the other attenuations.

Makes sense.

> Dan

Thanks for the clarifications. :)

Regards,
 - Christopher 		 	   		  
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