Re: [PD-dev] ugen start/stop (was garray loading)

Ok, I found out that the switch~ external was doing exactly what I wanted, sorry for the spam. However, I still wonder why this is a workaround, rather than a feature. I found out on the pd-dev archive, that the clicking with arrays was an issue. So I guess I am not the only one facing those problems. I first tought that the switch~ object was too cpu greedy, but it doesn't change anything ... Just a thought

Best

S.

2008/4/1, Sylvain Le Beux artheist@gmail.com:

Hi,

I think I figured out how dsp on/off was handling with garrays. Let's climb up hierachies. So, the generic setarray function (that can be found in most of externals dealing with arrays) use the function :

garray_usedindsp(x);

This function is defined in g_array.c like this :

void garray_usedindsp(t_garray *x) { x->x_usedindsp = 1; }

This usedindsp flag then sets the following (still in g_array.c) :

if (x->x_usedindsp) canvas_update_dsp();

Let's then look at canvas_update_dsp function, defined in g_canvas.c :

void canvas_update_dsp(void) { if (canvas_dspstate) canvas_start_dsp(); }

I guess canvas_dspstate is one on dsp start and zero on dsp off ... So when turning dsp on, it launches canvas_start_dsp, allright.

static void canvas_start_dsp(void) { t_canvas *x; if (canvas_dspstate) ugen_stop(); else sys_gui("pdtk_pd_dsp ON\n"); ugen_start();

for (x = canvas_list; x; x = x->gl_next)
    canvas_dodsp(x, 1, 0);

canvas_dspstate = 1;

}

We're almost at it, so the first thing is that when turning dsp on, it turns ugen off, which seems quite strange to me, but I supposed it's for being sure and then is start the ugen. Ok, well, why not. Let's now have a look at d_ugen.c

void ugen_stop(void) { t_signal *s; int i; if (dsp_chain) { freebytes(dsp_chain, dsp_chainsize * sizeof (t_int)); dsp_chain = 0; } signal_cleanup();

}

void ugen_start(void) { ugen_stop(); ugen_sortno++; dsp_chain = (t_int *)getbytes(sizeof(*dsp_chain)); dsp_chain[0] = 0; dsp_chainsize = 1; if (ugen_currentcontext) bug("ugen_start"); }

So,here we are, when turning dsp on, we anyway call ugen_start, which stop the ugen, and here is the problem I have. When executing ugen_stop, it flushes out the dspchain buffer, argh ... and does the signal_cleanup So, it results for me in a click anytime I restart the dsp, because previous unfinished buffer was flushed out beforehand. But, I also saw that just below definition of signal_cleanup function, lies a function called signal_makereusable. Does this mean that it is possible to freeze and/or save the current state of any signal before switching dsp off ? If yes, where should this function lie ? Sorry for my poor knowledge of internal Pd dsp functions.

Best

Sylvain