Re: Paremeter changes by the user
Re: Paremeter changes by the user
- Subject: Re: Paremeter changes by the user
- From: Aristotel Digenis <email@hidden>
- Date: Fri, 18 Jun 2004 21:07:29 +0100
Thank you Brian and Bill,
Good point, about calling the GetParameter function in the rendering and
therefore having the latest value on a per sample basis. However I have
chosen to go with the SetParameter when a slider is changed because I
will actually be doing some calculations on that incoming parameter
before its use in the render stage. I was also a bit confused with the
two SetParameter functions, one that takes 2 arguements and one that
takes more. I now have it working just fine.
Out of curiosity, calling the GetParameter function for the parameter on
every sample would take more processing power than having the value set
only when the slider is moved?
Thanks!!!
William Stewart wrote:
Aristotel
This is quite correct - unless you are doing something when the
parameter values changes, you only need to get the parameter when you
are doing rendering, so don't need to overwrite SetParameter...
Bill
On 17/06/2004, at 2:31 PM, Brian Willoughby wrote:
There may be no need to have a variable that is updated. You could
simply
wait until the render call and set a local variable by calling
GetParameter().
Depending upon which CoreAudio effect class you use, this
technique will even
support sample-acurate parameter changes, because render will be
called with
smaller buffers as the parameter changes.
The only truly necessary class variables in AudioUnits are state
variables
which need to be maintained between render calls. All parameters
can be loaded
into local register variables using GetParameter() before
beginning the
processing loop.
Brian Willoughby
Sound Consulting
Begin forwarded message:
That is starting to make things clearer but I still have a few
questions
I would like to understand. Since the UI calls the SetParameter
function
automatically. So this would mean that I need to override/redefine
the
SetParameter function so that there is a switch command to check
which
parameter has been updated and update the coresponding variable.
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Aristotel Digenis
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