The 'Slide' float component

malc · 24 May 2005

Hi lalo,

Interesting that you tried that because we initially created the Slide component to do just that. Of course as you've seen it doesn't work because the timers can only generate a maximum of 100 triggers per second which is too slow.

We decided to keep the component anyway because it can be used for other things - animation being one application.

That's the bad news.

The good news is that we have a solution which I think you'll be pretty happy with. If you give me 10 mins or so I'll post again and show you 🙂

malc · 24 May 2005

Ok lalo, here you go - feel free to skip the ramble that follows and go straight to the schematic at the bottom.

As you've said, up until now the best solution to the zipper noise problem has been the smooth module. This uses the code component to provide a simple low-pass filter (code courtesy of Stefan - thanks).

The problem with this is that it gets linked into the poly section code and eats a bit of cpu even if it's not being used. We originally thought that we could create something that was outside of the poly section that would only run when triggered. However, we found that this 'something' would need to run very fast in order to be of any use and this led us back to the poly section again.

The solution is pretty obvious and is made possible by the way that SM dynamically compiles code. All you need to do is have a way of adding in the smooth code when you need it. So what we've done is create a module that uses a selector to switch the float module in and out of the poly section code.

By doing this you take advantage of the processing power of the compiled code to do the smoothing and when you're done this gets taken out of the loop to maximise performance. In short, you can have your cake and eat it 🙂

The example below shows a 'de-zipper' module attached to a slider that is controlling the frequency of a sine wave osc. I've attached a Text View component to the Poly to Mono so that you can actually see the code changing as you start and stop moving the slider.

[old link]

Shifrin · 24 May 2005

What an elegant solution malc, very clever 🙂

Shif.

malc · 24 May 2005

Gotta give Jorge alot of the credit - it was his idea to swap the smooth in and out, I just had to work out how.

lalo · 25 May 2005

Oh yeah! guys Jorge and Malc what an elegant solution m8z 🙂

this lemme think about what jorge said about the 'switching noise' thing 😉 Glitches when doin' switching operations

great i'll try it today thanx

lalo