jsynthlib-devel

[Jsynthlib-devel] What is the JSL way to deal with negative param values?

[Steven S. <ste...@co...>]

Hello -
When a parameter has values in a range of say, -60 to +12 represented in 
the sysex as C4 to 0C, are there existing methods that understand those 
values?  Is anyone aware of a synth editor that deals with this type of 
data?
Thanks -
Steve

RE: [Jsynthlib-devel] What is the JSL way to deal with negative param values?

[Steven S. <ste...@co...>]

> Two things to watch out for:
 > * In Java, bytes are signed.   So if the range is 0..255 before, 
 > casting it to a (Byte) will change that to -128..127.  Thus, reading 
 > patch.sysex[index] may yield negative numbers.  I had to compensate in 
 > my CZModel.getByte.
 
 This is what I want.  How can I get this behavior in a model class?


-----Original Message-----
From: jsy...@li...
[mailto:jsy...@li...] On Behalf Of Steven
Schmidt
Sent: Tuesday, March 22, 2005 6:00 PM
To: jsy...@li...
Subject: [Jsynthlib-devel] What is the JSL way to deal with negative param
values?

Hello -
When a parameter has values in a range of say, -60 to +12 represented in 
the sysex as C4 to 0C, are there existing methods that understand those 
values?  Is anyone aware of a synth editor that deals with this type of 
data?
Thanks -
Steve



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Re: [Jsynthlib-devel] What is the JSL way to deal with negative param values?

[Joe E. <jo...@em...>]

Steven Schmidt wrote:

>>Two things to watch out for:
>>    
>>
> > * In Java, bytes are signed.   So if the range is 0..255 before, 
> > casting it to a (Byte) will change that to -128..127.  Thus, reading 
> > patch.sysex[index] may yield negative numbers.  I had to compensate in 
> > my CZModel.getByte.
> 
> This is what I want.  How can I get this behavior in a model class?
>  
>
Hmmm.... strange.

You might have a problem. Since your sysex spec uses C4 (-60) through 0C 
(12), the numbers match up (as opposed to, say, 0x00 to represent -60 
and 0x49 to represent 12) so that the widget/param-model doesn't have to 
add/subtract anything to the number before it stores it. The only tricky 
part is if the widgets will try to store negative values... and if the 
param-models handle it correctly.

I might take a look later.

- Joe

Re: [Jsynthlib-devel] What is the JSL way to deal with negative param values?

[Bill Z. <wrz...@po...>]

Steven Schmidt wrote:

> > * In Java, bytes are signed.   So if the range is 0..255 before, 
> > casting it to a (Byte) will change that to -128..127.  Thus, reading 
> > patch.sysex[index] may yield negative numbers.  I had to compensate in 
> > my CZModel.getByte.
> 
> This is what I want.  How can I get this behavior in a model class?
>
>  
>
You get it all for free.  Bytes are already signed, so if your numbers 
are in the range -128..127,  things will just work.  You can read and 
write patch.sysex[index], and you'll get what you expect.  If instead 
your values are 128..255, then things will half work -- you can write to 
patch.sysex[index] just fine, but when you read it back, it will be in 
the range -128..127.

Note that this goofiness is on top of the fact that your synth has 
probably scrambled the bytes a little to get around the restrictions of 
the sysex message.  So you need to deal with that, on top of dealing 
with signed bytes.

The easiest way to learn is to just do it, see where it breaks, then get 
help with that.  Don't be afraid, it's only code!

-Bill