[linux-audio-dev] Plugin APIs (again)

[David Olofson]

(Commenting on my own reply. Just thinking too much as usual. :-)

> > > 	/*
> > > 	 * create: instantiate the plugin
> >
> > Maybe better to stiuck to LADSPA nomenclature? It might not be
> > perfect, but it would avoid confusion.
>
> Here's another idea (from Audiality):
>
> typedef enum
> {
> 	FX_STATE_CLOSED = 0,
> 	FX_STATE_OPEN,
> 	FX_STATE_READY,
> 	FX_STATE_PAUSED,
> 	FX_STATE_RUNNING,
> 	FX_STATE_SILENT,
> 	FX_STATE_RESTING
> } a_fxstates_t;
>
> typedef struct a_plugin_t
> {
> 	...
> 	/* Plugin state management */
> 	int (*state)(struct a_plugin_t *p, a_fxstates_t new_state);
> 	...
> } a_plugin_t;

Maybe I should point out that a_plugin_t is the *instance* type for 
an Audiality plugin. Currently, I use a single entry to instantiate a 
plugin. Example:

void delay_init(struct a_plugin_t *p)
{
	p->state = delay_state;
	p->control = delay_control;
	p->process = delay_process;
	p->process_r = delay_process_r;
}

I suppose one could add a state FX_STATE_VOID (or something) below 
FX_STATE_CLOSED, and move instantiation and destruction (which is a 
NOP as of now, as the host manages the a_plugin_t structs) into the 
state() callback. Then just export the state() call, instead of an 
extra init func. (Or use a "fake" state() call if desired, which 
installs the real one in the provided a_plugin_t struct - coder's 
choice.)

However, one should probably have some more arguments for the init 
calls, to support multiple plugins, variants and stuff in a single 
.so - so I guess it's better kept the way it is... :-)


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

.- Coming soon from VaporWare Inc...------------------------.
| The Return of Audiality! Real, working software. Really!  |
| Real time and off-line synthesis, scripting, MIDI, LGPL...|
`-----------------------------------> (Public Release RSN) -'
.- M A I A -------------------------------------------------.
|    The Multimedia Application Integration Architecture    |
`----------------------------> http://www.linuxdj.com/maia -'
   --- http://olofson.net --- http://www.reologica.se ---