Ross Bencina wrote:
> Perhaps on some platforms. But for windows:
> "The default scope of DLL variables is the same as that of variables
> declared in the application. Global variables in a DLL source code file are
> global to each process using the DLL. Static variables have scope limited to
> the block in which they are declared. As a result, each process has its own
> instance of the DLL global and static variables by default."
>
> So a dll instance is not a class. My suggestion would be to have sa.c export
> a single method: saengine_alloc()
> which returns a pointer to an interface (structure of function pointers)
> containing a clean up routine (destructor) and whatever other functions are
> deemed necessary.
>
> Alternately, SFrontPlugInit() could become SFrontPlugCreate(), and the
> SFrontPlugInfo could contain engine state, which would be passed back to
> SFrontPlugProcessNextNFrames() to perform processing. Or even better, make
> ProcessNextNFrames() a function pointer member of SFrontPlugInfo. It
> SFrontPlugInfo is the same for all instances of a plug (which it probably
> is) you could have SFrontPlugInfo and SFrontPlugInstance.
You are quite right Ross, I had completely overlooked this multiple instance
question, and yes we could have SFrontPlugCommonInfo and SFrontPlugInstance.
So I guess we are going to settle on a single exported function :
SFrontPlugCreate(), receiving sample rate as an argument and returning a
pointer to a new SFrontPlugInstance structure.
Each SFrontPlugInstance would hold its own engine state plus :
- a pointer to the SFrontPlugCommonInfo structure.
- a pointer to the SFrontPlugProcessNextNFrames() function. Arguments to this
function should comprise a pointer to the instance, the number of frames N
(may be different from one call to the next), a pointer to a MidiInputEvents
structure compatible with VST's (pointing to events falling into the time
slice, frame-accurately timestamped relative to the beginning of the time
slice, each event must be processed at k-pass immediately following timestamp,
or following ones if necessary as _no event must be disregarded_ : think of
RPN/NRPN), a pointer to an array of audio input float buffer pointers, and a
pointer to an array of audio output float buffer pointers.
SFrontPlugCommonInfo would hold common plug info (audio input and output
widths…) plus a pointer to the SFrontPlugDelete() function, the latter
receiving a pointer to the instance as an argument.
Michael, is that OK with you ? I guess you've coded it already ;-) That java
thing you sent us is javanese for me BTW (don't know java), I was glad I knew
what Noise is supposed to do :-)
-- Greetings, Michel ......................................................................... Michel Jullian Directeur General email mj@exbang.com Exbang Industries S.A. Mas Chauvain route de Villeneuve tel +33(0) 499 529 878 Maurin 34970 Lattes France fax +33(0) 499 529 879 .........................................................................
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