[linux-audio-dev] XAP: Some thoughts on control ramping

[David Olofson]

On Tuesday 21 January 2003 10.19, Steve Harris wrote:
[...]
> > Another idea:
> > Since we need that (duration == 0) test anyway, why not have it
> > explicitly stop ramping as well, so we can connect non-ramped
> > outputs to ramped inputs and vice versa?
>
> I'd say that has different semantics, and so should be a seperate
> event. Say... SET ;)

Well, yeah. Back at square 1! :-)

Though, the 0 test is still really a fix for a logical glitch that 
appears in the borderland between continous and sampled time.

So, if the test is needed anyway, is it all that bad to "abuse" it a 
little, to make it usable as a SET event as well? I don't really like 
it, but I don't like a special SET event any more...

Then again:
	  case RAMP:
		if(ev->arg2)
		{
			v->ic[ev->index].dv = ev->arg1 << RAMP_BITS;
			v->ic[ev->index].dv -= v->ic[ev->index].v;
			v->ic[ev->index].dv /= ev->arg2 + 1;
			break;
		}
	  case SET:
                v->ic[ev->index].v = ev->arg1 << RAMP_BITS;
                v->ic[ev->index].dv = 0;
		break;


Note that while this fixes the broken 0 duration case, it also has 
the side effect that RAMP(value, 0) becomes equivalent to SET(value). 
So, you don't really need to use the SET event explicitly at all.


//David Olofson - Programmer, Composer, Open Source Advocate

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