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Re: Parameter Display Updating
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Re: Parameter Display Updating


  • Subject: Re: Parameter Display Updating
  • From: William Stewart <email@hidden>
  • Date: Mon, 28 Jun 2004 09:55:58 -0700

On 28/06/2004, at 4:57 AM, Aristotel Digenis wrote:

> Hello everybody,
>
> I am having a problem with updating parameters to updated values.
>
> Lets say I have two parameters on the default GUI, 1 indexed (drop
> down menu) and a slider. The drop down menu has values between 1 and
> 16 and they represent different speakers. The slider value is meant to
> be the amplitude of the speaker. So the user can select say Speaker 5
> from the drop down parameter and the slider should recall the
> amplitude last set for that speaker.
>
> In the SetParameter function I store the value of the drop down
> parameter into an integer called speakerInFocus. While still in the
> case statement for the drop down parameter, I call
> AUBase::SetParameter(amplitude, kAudioUnitScope_Global, 0,
> speakerAmplitude[speakerInFocus], 0); to update the amplitude
> parameter to the value of that speaker. This did not work(code shown
> below).

You need to declare *any* parameters that can have their values changed
by another parameter as a meta parameter... Then it will just work.

SetParameter will then go and set the value of the parameter - but
because you've marked amplitude as a meta parameter, its value will be
checked when any other parameter on the AU changes and the UI will
update appropriately without you having to do anything else

Bill

>
> (Also...what is the difference betweeen AudioUnitSetParameter() and
> SetParameter()? None right?)
>
> Thank you
>
> - - - - - - - - - - - - - -
> //In the constructor
> float speakerAmplitude[16];
> int speakerInFocus = 0;
> for(int i = 0; i < 16; i++)
> {
> speakerAmplitude[i] = 0.5;
> }
>
> SetParameter(speakerNumber, kAudioUnitScope_Global, 0, speakerInFocus,
> 0);
> SetParameter(amplitude, kAudioUnitScope_Global, 0,
> speakerAmplitude[speakerInFocus], 0);
>
> //Later in the program
> ComponentResult BDecoder::SetParameter(AudioUnitParameterID iID,
> AudioUnitScope iScope, AudioUnitElement iElem, Float32 rValue, UInt32
> iSchedule)
> {
> if (iScope==kAudioUnitScope_Global && iElem==0)
> {
> switch (iID)
> {
> case speakerNumber:
> speakerInFocus = (int) rValue;
> AUBase::SetParameter(amplitude, kAudioUnitScope_Global,
> 0, speakerAmplitude[speakerInFocus], 0);
> break;
> case amplitude:
> speakerAmplitude[speakerInFocus] = rValue;
> break;
> } }
> return AUBase::SetParameter(iID, iScope, iElem, rValue, iSchedule);
> }
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>
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  • Follow-Ups:
    • Re: Parameter Display Updating
      • From: Aristotel Digenis <email@hidden>
References: 
 >Parameter Display Updating (From: Aristotel Digenis <email@hidden>)

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