[Stk] problems implementing polyphony...

[Tristan Matthews]

2012/9/17 Rumi Humphrey <rumi at refresh.vu>:
> I think you can get your (modified for momu) FM class to compile if you
> comment out this line in FM.h:
>
> virtual StkFrames& tick( StkFrames& frames, unsigned int channel = 0 ) = 0;
>
> I'm not exactly sure why that is or how to use tick with frames i think the
> MoMu version of STK might implement it differently or something.
>
> Unfortunately though doing this and using arrays instead of vectors didn't
> seem to help performance that much at least not on my ipod touch. I'm still
> only able to get one voice to play using HevyMetl.

How does your hardware handle denormal floats? The FM class contains a
TwoZero filter,
which I believe can lead to denormals. You could try adding a small DC
offset the samples
before they are input to the TwoZero filter.

This article has some background, as well as how to test denormal
computation on your hardware:
http://stackoverflow.com/questions/9350810/denormalized-floating-point-in-objective-c

The only other thing I might try is changing StkFloat from double to float.

Best,
Tristan

>
> On Sep 17, 2012, at 7:27 PM, Patrick J. Collins wrote:
>
> Hmmm..  So after I put replaced the FM files with those two that you
> provided, building failed first because of:
>  #include "SKINI.msg"
>
> Claiming that file was not found...  I changed it to what it was
> previously:
>
>  #include "Skini_msg.h"
>
> Then the .cp failed with:
>        if ( nOperators_ == 0 ) {
>            oStream_ << "FM::FM: Number of operators must be greater than
> zero!";
>            handleError( StkError::FUNCTION_ARGUMENT );
>        }
>
> Saying "use of undeclared identifier oStream_"...  So I changed that to
> errorString_ as it was before...
>
> Then finally after doing that, the build fails at a point in my own code
> where I am doing:
>
>  // in my .h:
>    HevyMetl *instrument[4];
>
>  // in my .mm:
>    voicer = new Voicer();
>    instrument[0] = new HevyMetl();
>    instrument[1] = new HevyMetl();
>    voicer->addInstrument(instrument[0]);
>    voicer->addInstrument(instrument[1]);
>    voicer->silence();
>
> ...  It's failing at "new HevyMetl()" saying "Allocating an object of
> abstract class type 'HevyMetl'"...
>
> Patrick J. Collins
> http://collinatorstudios.com
>
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-- 
Tristan Matthews
web: http://tristanswork.blogspot.com