path: root/src/z_noise.c

/*
	30041999

	two bandlimited noise gnerators based on DODGE/JERSE "computer music" c3.9 : RANDI & RANDH 
	
	I do not care for copyrights
	(all in all, the used noise~-code (in fact, the pseude-random-code) is from Miller Puckette 
	and I made only very few modifications so look out for the LICENSE.TXT delivered with 
	puredata for further (c)-information

	forum für umläute 1999

	this is in fact the very same as the late "NOISE.C", except that I tried to optimize the code a little
	bit(by partially removing those very expensive if..then's in about 15 minutes, so there are thousands of
	new bugs very likely

	14071999
	finally added changing seeds, this is to prevent to noise~-units to output the very same, something quite
	unnatural even for pseudo-random-noise
*/

#include "zexy.h"
#ifdef NT
#pragma warning( disable : 4244 )
#pragma warning( disable : 4305 )
#endif

/* general */

typedef struct _nois
{
	t_object x_obj;
	int val;
	t_float current;
	t_float decrement;
	t_float updater;		
	t_float to_go;
} t_nois;


static void set_freq(t_nois *x, t_floatarg freq)
{
	x->updater = (freq > 0) ? sys_getsr() / freq : 1;
	if (x->updater < 1)
	{
		x->updater = 1;
	}
	x->to_go = 0;
}


/* ------------------------ noish~ ----------------------------- */ 

static t_class *noish_class;

static t_int *noish_perform(t_int *w)
{
	t_nois *x = (t_nois *)(w[1]);
	t_float *out = (t_float *)(w[2]);
	int n = (int)(w[3]);
	
	int *vp = (int *)(&x->val);
	int i_value = *vp;
	t_float f_value = ((float)((i_value & 0x7fffffff) - 0x40000000)) *
			(float)(1.0 / 0x40000000);
	t_float all_to_go = x->updater;
	t_float still_to_go = x->to_go;

	if (all_to_go == 1)
	{	/* this is "pure white" noise, so we have to calculate each sample */ 
		while (n--)
		{
			i_value *= 435898247;
			i_value += 382842987;
			*out++ = ((float)((i_value & 0x7fffffff) - 0x40000000)) * (float)(1.0 / 0x40000000);
		}
	}
	else
		if (n < still_to_go)
		{	/* signal won't change for the next 64 samples */ 
			still_to_go -= n;
			while (n--)
			{
				*out++ = f_value;
			}
		}
		else
			if (all_to_go + still_to_go > n)
			{	/* only one update calculation necessary for 64 samples !!! */ 
				while (still_to_go-- > 0)
				{
					n--;
					*out++ = f_value;
				}

				still_to_go += all_to_go + 1;

				i_value *= 435898247;
				i_value += 382842987;
				f_value = ( (float)((i_value & 0x7fffffff) - 0x40000000) ) * (float)(1.0 / 0x40000000);

				while (n--)
				{
					still_to_go--;
					*out++ = f_value;
				}
			}
			else
			{	/* anything else */ 
				while (n--)
				{
					if (still_to_go-- <= 0)		/* update only if all time has elapsed */ 
					{
						still_to_go += all_to_go;

						i_value *= 435898247;
						i_value += 382842987;
			
						f_value = ( (float)((i_value & 0x7fffffff) - 0x40000000) ) * (float)(1.0 / 0x40000000);		
					}
					*out++ = f_value;
				}
			}


	*vp = i_value;
	 x->updater = all_to_go;
	 x->to_go = still_to_go;

	return (w+4);
}

static void noish_dsp(t_nois *x, t_signal **sp)
{
  post("sr=%f\nsn=%f", sp[0]->s_sr, sp[0]->s_n);
  dsp_add(noish_perform, 3, x, sp[0]->s_vec, sp[0]->s_n);
}

static void noish_helper(void)
{
	post("\n%c noish~\t:: a bandlimited pseudo-noise generator", HEARTSYMBOL);
	post("<freq>\t : sampling-frequency (in Hz)\n"
		"'help'\t : view this");
	post("creation : \"noish~ [<freq>]\"\t: ('0'(default) will produce 'white' noise)\n");
	post("note\t : the seed of the pseudo-noise generator changes from\n"
		"\t     instance to instance, so two noish~-objects created at the\n"
		"\t     same time will produce dífferent signals, something the original\n"
		"\t     noise~-object misses\n");
	post("for further details see DODGE/JERSE \"computer music\" c3.9\n");
}

static void *noish_new(t_floatarg f)
{
	t_nois *x = (t_nois *)pd_new(noish_class);

	static int init = 307;
	x->val = (init *= 13);

	set_freq(x, f);

	outlet_new(&x->x_obj, gensym("signal"));
	return (x);
}

void noish_setup(void)
{
	noish_class = class_new(gensym("noish~"), (t_newmethod)noish_new, 0, sizeof(t_nois), 0, A_DEFFLOAT, 0);

	class_addfloat(noish_class, set_freq);
	class_addmethod(noish_class, (t_method)noish_dsp, gensym("dsp"), 0);

	class_addmethod(noish_class, (t_method)noish_helper, gensym("help"), 0);
	class_sethelpsymbol(noish_class, gensym("zexy/noish~"));
}



/* ------------------------ noisi~ ----------------------------- */ 

static t_class *noisi_class;

static t_int *noisi_perform(t_int *w)
{
	t_nois *x = (t_nois *)(w[1]);
	t_float *out = (t_float *)(w[2]);
	int n = (int)(w[3]);

	int *vp = (int *)(&x->val); /* what the ... */ 
	int i_value = *vp;
	t_float f_value = x->current;
	t_float decrement = x->decrement;
	t_float all_to_go = x->updater;
	t_float still_to_go = x->to_go;

	if (all_to_go == 1)
	{	/* this is "pure white" noise, so we have to calculate each sample */ 
		while (n--)
		{
			i_value *= 435898247;
			i_value += 382842987;
			*out++ = ((float)((i_value & 0x7fffffff) - 0x40000000)) * (float)(1.0 / 0x40000000);
		}
	}
	else
		if (n < still_to_go)
		{	/* signal won't change for the next 64 samples */ 
			still_to_go -= n;
			while (n--)
			{
				*out++ = (f_value -= decrement);
			}
		}
		else
			if (all_to_go + still_to_go > n)
			{	/* only one update calculation necessary for 64 samples !!! */ 
				while (still_to_go-- > 0)
				{
					n--;
					*out++ = (f_value -= decrement);
				}


				still_to_go += all_to_go + 1;

				decrement = (
					(f_value = ((float)((i_value & 0x7fffffff) - 0x40000000)) * (float)(1.0 / 0x40000000)) -
					((float)(((i_value = i_value * 435898247 + 382842987) & 0x7fffffff) - 0x40000000)) * (float)(1.0 / 0x40000000)
					) / all_to_go;


				while (n--)
				{
					still_to_go--;
					*out++ = (f_value -= decrement);
				}
			}
			else
			{	/* anything else */ 
				while (n--)
				{
					if (still_to_go-- <= 0)		/* update only if all time has elapsed */ 
					{
						still_to_go += all_to_go;

						decrement = (
							(f_value = ((float)((i_value & 0x7fffffff) - 0x40000000)) * (float)(1.0 / 0x40000000)) -
							((float)(((i_value = i_value * 435898247 + 382842987) & 0x7fffffff) - 0x40000000)) * (float)(1.0 / 0x40000000)
							) / all_to_go;
					}
					*out++ = (f_value -= decrement);
				}
			}

	*vp = i_value;
	x->current = f_value;
	x->decrement = decrement;
	x->to_go = still_to_go;

	return (w+4);
}

static void noisi_dsp(t_nois *x, t_signal **sp)
{
	dsp_add(noisi_perform, 3, x, sp[0]->s_vec, sp[0]->s_n);
}


static void noisi_helper(void)
{
	post("\n%c noisi~\t:: a bandlimited interpolating pseudo-noise generator", HEARTSYMBOL);
	post("<freq>\t : sampling-frequency (in Hz)\n"
		"'help'\t : view this");
	post("creation : \"noisi~ [<freq>]\"\t: ('0'(default) will produce 'white' noise)\n");
	post("note\t : the seed of the pseudo-noise generator changes from\n"
		"\t     instance to instance, so two noisi~-objects created at the\n"
		"\t     same time will produce different signals, something the original\n"
		"\t     noise~-object misses\n");
	post("for further details see DODGE/JERSE \"computer music\" c3.9\n");
}

static void *noisi_new(t_floatarg f)
{
	t_nois *x = (t_nois *)pd_new(noisi_class);

	static int init = 4259;
	x->val = (init *= 17);

	set_freq (x, f);

	outlet_new(&x->x_obj, gensym("signal"));
	return (x);

}

void noisi_setup(void)
{
	noisi_class = class_new(gensym("noisi~"), (t_newmethod)noisi_new, 0, sizeof(t_nois), 0, A_DEFFLOAT, 0);

	class_addfloat(noisi_class, set_freq);
	class_addmethod(noisi_class, (t_method)noisi_dsp, gensym("dsp"), 0);

	class_addmethod(noisi_class, (t_method)noisi_helper, gensym("help"), 0);
	class_sethelpsymbol(noisi_class, gensym("zexy/noisi~"));
}

/* global setup routine */

void z_noise_setup(void)
{
	noish_setup();
	noisi_setup();
}