Re: Interactive Effects

[Johann D. <jo...@Do...>]

On Sat, 26 Jan 2002, Bj|rn Augustsson wrote:

> Quoting Johann Deneux <jo...@Do...>:
> > On Sat, 26 Jan 2002, Rodrigo Damazio wrote:
> > > Johann Deneux wrote:
> > > > On Sat, 26 Jan 2002, Rodrigo Damazio wrote:
> > >    Okay, will do so...also, is itme who has an outdated version of 
> > > input.h, or does it really not have ET Ramp, Damper, and Inertia?? And 
> > 
> > Ramps did not seem to useful to me. Indeed, they can be realised using
> > other effects, for example, using a shaped constant effect.
> 
> You can't emulate a shaped ramp effect that way though.

Right. You can however use sawtooth up or down, though. Set the effect
length to play for one period only, and set the magnitude and offset to
the "right" values. It is then still possible to add a shape.
The point is, it seems there are different ways to achieve one given
effect. Should we have a "non prime" set of effects ?

>[...]
> > The other solution would be to hide these parameter blocks and let the
> > driver optimize its memory usage. This looks pretty ambitious to me,
> > though.
> 
> Absolutely. Again, it could be done in a library.
> 
> Hmm, Rodrigo, did you have a look at what the MS DirectInput looks like? How
> do they do this?
> 
> > The last solution is to go for "1 parameter block - 1
> > effect" solution. It's safe, easy to implement, but it kills the
> > possibility to share parameters between several effects.
> 
> Right. 
>  
> Now for custom effects, I think we should have a separate call to upload
> those. Having the variable length array thing you suggested is nice, but
> then we can't add more fields to the strut after that if we choose to
> later. (Or can we? I seem to remember that the variable length array has
> to be the last member of a struct, but I'm not sure...)

You are right. Anyway, I think we should stick to ANSI C. Not for the
driver itself of course, but for the user-visible headers.
Yet another solution would be that the user provides a pointer to a buffer
describing the custom effect.
Isn't this solution nicer ? I personnaly dislike the idea of having
several ioctls perform one operation (the uploading of a full-effect)

> 
> /August.
> 
By the way, how should we call you ? August or Bj-pipe-rn :) ?

-- 
Johann Deneux