swh-lv2 1.0.15+git20151104~repack0-1 / usr / lib / lv2 / svf-swh.lv2 / plugin.ttl

@prefix : <http://lv2plug.in/ns/lv2core#> .
@prefix swh: <http://plugin.org.uk/swh-plugins/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix doap: <http://usefulinc.com/ns/doap#> .
@prefix swhext: <http://plugin.org.uk/extensions#> .
@prefix pg: <http://lv2plug.in/ns/ext/port-groups#> .
@prefix pprops: <http://lv2plug.in/ns/ext/port-props#> .

swh:svf a :Plugin ;
   a :FilterPlugin ;

   doap:name "State Variable Filter" ;
   doap:maintainer [
      foaf:name "Steve Harris";
      foaf:homepage <http://plugin.org.uk/> ;
      foaf:mbox <mailto:steve@plugin.org.uk> ;
   ] ;
   doap:license <http://usefulinc.com/doap/licenses/gpl> ;
   :documentation <http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#svf> ;

   :pluginProperty :hardRtCapable ;
    
   :port [
     a :InputPort, :AudioPort ;
     :name "Input" ;
     :index 0 ;
     :symbol "input" ;
     :minimum -1 ;
     :maximum 1 ;
     
   ] ;
  
   :port [
     a :OutputPort, :AudioPort ;
     :name "Output" ;
     :index 1 ;
     :symbol "output" ;
     :minimum -1 ;
     :maximum 1 ;
     
   ] ;
  
   :port [
     a :InputPort, :ControlPort ;
     :name "Filter type (0=none, 1=LP, 2=HP, 3=BP, 4=BR, 5=AP)" ;
     :index 2 ;
     :symbol "filt_type" ;
     :minimum 0 ;
     :maximum 5 ;
     
     :default 0.0 ;
     :portProperty :integer ;
   ] ;
  
   :port [
     a :InputPort, :ControlPort ;
     :name "Filter freq" ;
     :index 3 ;
     :symbol "filt_freq" ;
     :minimum 0 ;
     :maximum 6000 ;
     
     :default 440.0 ;
   ] ;
  
   :port [
     a :InputPort, :ControlPort ;
     :name "Filter Q" ;
     :index 4 ;
     :symbol "filt_q" ;
     :minimum 0 ;
     :maximum 1 ;
     
     :default 0.25 ;
   ] ;
  
   :port [
     a :InputPort, :ControlPort ;
     :name "Filter resonance" ;
     :index 5 ;
     :symbol "filt_res" ;
     :minimum 0 ;
     :maximum 1 ;
     
     :default 0.0 ;
   ] ;
  
   swhext:code """
#include "ladspa-util.h"

// Constants to match filter types
#define F_LP 1
#define F_HP 2
#define F_BP 3
#define F_BR 4
#define F_AP 5

// Number of filter oversamples
#define F_R 3

/* Structure to hold parameters for SV filter */

typedef struct {
	float f;     // 2.0*sin(PI*fs/(fc*r));
	float q;     // 2.0*cos(pow(q, 0.1)*PI*0.5);
	float qnrm;  // sqrt(m/2.0f+0.01f);
	float h;     // high pass output
	float b;     // band pass output
	float l;     // low pass output
	float p;     // peaking output (allpass with resonance)
	float n;     // notch output
	float *op;   // pointer to output value
} sv_filter;

/* Store data in SVF struct, takes the sampling frequency, cutoff frequency
   and Q, and fills in the structure passed */

static inline void setup_svf(sv_filter *sv, float fs, float fc, float q, int t) {
	sv->f = 2.0f * sin(M_PI * fc / (float)(fs * F_R));
	sv->q = 2.0f * cos(pow(q, 0.1f) * M_PI * 0.5f);
	sv->qnrm = sqrt(sv->q/2.0+0.01);
	switch(t) {
	case F_LP:
		sv->op = &(sv->l);
		break;
	case F_HP:
		sv->op = &(sv->h);
		break;
	case F_BP:
		sv->op = &(sv->b);
		break;
	case F_BR:
		sv->op = &(sv->n);
		break;
	default:
		sv->op = &(sv->p);
	}
}

/* Run one sample through the SV filter. Filter is by andy@vellocet */

static inline float run_svf(sv_filter *sv, float in) {
	float out;
	int i;

	in = sv->qnrm * in ;
	for (i=0; i < F_R; i++) {
		// only needed for pentium chips
		in  = flush_to_zero(in);
		sv->l = flush_to_zero(sv->l);
		// very slight waveshape for extra stability
		sv->b = sv->b - sv->b * sv->b * sv->b * 0.001f;

		// regular state variable code here
		// the notch and peaking outputs are optional
		sv->h = in - sv->l - sv->q * sv->b;
		sv->b = sv->b + sv->f * sv->h;
		sv->l = sv->l + sv->f * sv->b;
		sv->n = sv->l + sv->h;
		sv->p = sv->l - sv->h;

		out = *(sv->op);
		in = out;
	}

	return out;
}

		""" ;

   swhext:callback [
     swhext:event "instantiate" ;
     swhext:code """
sample_rate = s_rate;

svf = calloc(1, sizeof(sv_filter));
		""" ;
   ] ;
  
   swhext:callback [
     swhext:event "activate" ;
     swhext:code """
setup_svf(svf, 0, 0, 0, 0);
		""" ;
   ] ;
  
   swhext:callback [
     swhext:event "cleanup" ;
     swhext:code """
free(plugin_data->svf);
		""" ;
   ] ;
  
   swhext:callback [
     swhext:event "run" ;
     swhext:code """
long int pos;

setup_svf(svf, sample_rate, filt_freq, filt_q, f_round(filt_type));

for (pos = 0; pos < sample_count; pos++) {
	buffer_write(output[pos], run_svf(svf, input[pos] + (svf->b * filt_res)));
}
		""" ;
   ] ;
  
   swhext:createdBy <http://plugin.org.uk/swh-plugins/toTurtle.xsl> .