Chebyshev filters

Makefile

@@ -79,7 +79,7 @@ COMPINCLUDE = $(edirs) $(eddirs) $(pindirs) $(bsdirs)
 
 
 
-WARNING_FLAGS = -Wall -Wwrite-strings -Wunsupported -Wall -Wextra -Wwrite-strings -Wno-unused-parameter -Wno-unused-function -Wno-missing-braces -Wno-incompatible-function-pointer-types -Wno-gnu-statement-expression -Wno-complex-component-init -pedantic
+WARNING_FLAGS = #-Wall -Wwrite-strings -Wunsupported -Wall -Wextra -Wwrite-strings -Wno-unused-parameter -Wno-unused-function -Wno-missing-braces -Wno-incompatible-function-pointer-types -Wno-gnu-statement-expression -Wno-complex-component-init -pedantic
 
 
 

source/engine/datastream.c

@@ -73,9 +73,24 @@ void ds_openvideo(struct datastream *ds, const char *video, const char *adriver)
     struct dsp_filter astream_filter;
     astream_filter.data = &ds->astream;
     astream_filter.filter = soundstream_fillbuf;
-    first_free_bus(astream_filter);
 
-    printf("Circbuf size is %u.\n", ds->astream.buf.len);
+    //struct dsp_filter lpf = lpf_make(8, 10000);
+    struct dsp_filter lpf = lpf_make(1, 200);
+    struct dsp_iir *iir = lpf.data;
+    iir->in = astream_filter;
+
+
+    struct dsp_filter hpf = hpf_make(1, 2000);
+    struct dsp_iir *hiir = hpf.data;
+    hiir->in = astream_filter;
+
+/*
+    struct dsp_filter llpf = lp_fir_make(20);
+    struct dsp_fir *fir = llpf.data;
+    fir->in = astream_filter;
+*/
+
+    first_free_bus(hpf);
 
     plm_set_video_decode_callback(ds->plm, render_frame, ds);
     plm_set_audio_decode_callback(ds->plm, render_audio, ds);

source/engine/dsp.c

@@ -4,6 +4,7 @@
 #include "limits.h"
 #include "math.h"
 #include "stdlib.h"
+#include "iir.h"
 
 #define PI 3.14159265
 
@@ -193,19 +194,225 @@ void osc_fillbuf(struct osc *osc, short *buf, int n)
 {
     for (int i = 0; i < n; i++) {
         short val = SHRT_MAX * osc->f(phasor_step(&osc->p));
-        buf[i*2] = buf[i*2+1] = val;
+        buf[i*CHANNELS] = buf[i*CHANNELS+1] = val;
     }
 }
 
-void gen_whitenoise(void *data, short *buf, int n)
+void gen_whitenoise(void *data, short *out, int n)
 {
     for (int i = 0; i < n; i++) {
-        for (int j = 0; j < 2; j++) {
-            buf[i*2+j] = (rand()>>15) - USHRT_MAX;
+        for (int j = 0; j < CHANNELS; j++) {
+            out[i*CHANNELS+j] = (rand()>>15) - USHRT_MAX;
         }
     }
 }
 
+void gen_pinknoise(void *data, short *out, int n)
+{
+    gen_whitenoise(NULL, out, n);
+
+    double b[2][7] = {0};
+    double ccof[6] = {0.99886, 0.99332, 0.96900, 0.8550, 0.55000, -0.76160};
+    double dcof[6] = {0.0555179, 0.0750759, 0.1538520, 0.3104856, 0.5329522, 0.0168960};
+
+    for (int i = 0; i < n; i++) {
+        for (int j = 0; j < CHANNELS; j++) {
+            double pink;
+            double white = (double)out[i*CHANNELS+j]/SHRT_MAX;
+
+            for (int k = 0; k < 5; k++) {
+                b[j][k] = ccof[k]*b[j][k] + white * dcof[k];
+                pink += b[j][k];
+            }
+
+            pink += b[j][5] + white*0.5362;
+            b[j][5] = white*0.115926;
+
+            out[i*CHANNELS+j] = pink * SHRT_MAX;
+        }
+    }
+    /*
+      *  The above is a loopified version of this
+      *  https://www.firstpr.com.au/dsp/pink-noise/
+    b0 = 0.99886 * b0 + white * 0.0555179;
+    b1 = 0.99332 * b1 + white * 0.0750759;
+    b2 = 0.96900 * b2 + white * 0.1538520;
+    b3 = 0.86650 * b3 + white * 0.3104856;
+    b4 = 0.55000 * b4 + white * 0.5329522;
+    b5 = -0.7616 * b5 - white * 0.0168980;
+    pink = b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
+    b6 = white * 0.115926;
+    */
+}
+
+short iir_filter(struct dsp_iir *iir, short val)
+{
+    float a = 0.f;
+
+    iir->dx[0] = (float)val/SHRT_MAX;
+    for (int i = 0; i < iir->n; i++)
+        a += iir->ccof[i] * iir->dx[i];
+
+    for (int i = iir->n-1; i > 0; i--)
+        iir->dx[i] = iir->dx[i-1];
+
+
+    for (int i =0; i < iir->n; i++)
+        a -= iir->dcof[i] * iir->dy[i];
+
+    iir->dy[0] = a;
+
+    for (int i = iir->n-1; i > 0; i--)
+        iir->dy[i] = iir->dy[i-1];
+
+
+
+    return a * SHRT_MAX;
+}
+
+void dsp_iir_fillbuf(struct dsp_iir *iir, short *out, int n)
+{
+    dsp_run(iir->in, out, n);
+
+    for (int i = 0; i < n; i++) {
+        short v = iir_filter(iir, out[i*CHANNELS]);
+
+        for (int j = 0; j < CHANNELS; j++) {
+           out[i*CHANNELS+j] = v;
+        }
+    }
+}
+
+struct dsp_iir new_iir(int poles, float freq)
+{
+    struct dsp_iir new;
+    new.poles = poles;
+    new.freq = freq;
+    new.n = new.poles+1;
+    new.ccof = malloc(new.n*sizeof(float));
+    new.dcof = malloc(new.n*sizeof(float));
+    new.dy = malloc(new.n*sizeof(float));
+    new.dx = malloc(new.n*sizeof(float));
+    return new;
+}
+
+struct dsp_filter lpf_make(int poles, float freq)
+{
+    struct dsp_iir *new = malloc(sizeof(*new));
+    *new = new_iir(poles, freq);
+
+  double fcf = new->freq*2/SAMPLERATE;
+  double sf = sf_bwlp(poles, fcf);
+
+  printf("Making LPF filter, fcf: %f, coeffs: %i, scale %1.15lf\n", fcf, new->n, sf);
+
+  int *ccof = ccof_bwlp(new->poles);
+  double *dcof = dcof_bwlp(new->poles, fcf);
+
+  for (int i = 0; i < new->n; i++) {
+      new->ccof[i] = ccof[i] * sf;
+      new->dcof[i] = dcof[i];
+  }
+
+  new->dcof[0] = 0.f;
+
+  free(ccof);
+  free(dcof);
+
+  printf("LPF coefficients are:\n");
+
+  for (int i = 0; i < new->n; i++) {
+      printf("%f, %f\n", new->ccof[i], new->dcof[i]);
+  }
+
+  struct dsp_filter lpf;
+  lpf.data = new;
+  lpf.filter = dsp_iir_fillbuf;
+
+  return lpf;
+}
+
+struct dsp_filter hpf_make(int poles, float freq)
+{
+  struct dsp_iir *new = malloc(sizeof(*new));
+  *new = new_iir(poles, freq);
+
+  double fcf = new->freq*2/SAMPLERATE;
+  double sf = sf_bwhp(new->poles, fcf);
+
+  int *ccof = ccof_bwhp(new->poles);
+  double *dcof = dcof_bwhp(new->poles, fcf);
+
+  for (int i = 0; i < new->n; i++) {
+      new->ccof[i] = ccof[i] * sf;
+      new->dcof[i] = dcof[i];
+  }
+
+    for (int i = 0; i < new->n; i++) {
+      printf("%f, %f\n", new->ccof[i], new->dcof[i]);
+  }
+
+  free(ccof);
+  free(dcof);
+
+  struct dsp_filter hpf;
+  hpf.data = new;
+  hpf.filter = dsp_iir_fillbuf;
+
+  return hpf;
+}
+
+short fir_filter(struct dsp_fir *fir, short val)
+{
+    float ret = 0.f;
+    fir->dx[fir->head] = (float)val/SHRT_MAX;
+
+    for (int i = 0; i < fir->n; i++) {
+        ret += fir->cof[i] * fir->dx[fir->head--];
+
+        if (fir->head < 0) fir->head = fir->n-1;
+    }
+
+    return ret * SHRT_MAX;
+}
+
+void dsp_fir_fillbuf(struct dsp_fir *fir, short *out, int n)
+{
+    dsp_run(fir->in, out, n);
+
+    for (int i = 0; i < n; i++) {
+        short val = fir_filter(fir, out[i*CHANNELS]);
+       // printf("%hd\n", val);
+
+        for (int j = 0; j < CHANNELS; j++)
+            out[i*CHANNELS + j] = val*5;
+    }
+}
+
+struct dsp_filter lp_fir_make(float freq)
+{
+    struct dsp_fir fir;
+    fir.freq = freq;
+    fir.n = 9;
+    fir.head = 0;
+    double fcf = freq * 2 / SAMPLERATE;
+    fir.dx = calloc(sizeof(float),  fir.n);
+    fir.cof = fir_lp(fir.n, fcf);
+
+    struct dsp_filter new;
+    new.data = malloc(sizeof(fir));
+    *(struct dsp_fir*)(new.data) = fir;
+    new.filter = dsp_fir_fillbuf;
+
+    for (int i = 0; i < fir.n; i++) {
+        printf("%f\n", fir.cof[i]);
+    }
+
+    return new;
+}
+
+
+
 struct dsp_delay dsp_delay_make(unsigned int ms_delay)
 {
     struct dsp_delay new;
@@ -226,7 +433,7 @@ void dsp_delay_filbuf(struct dsp_delay *delay, short *buf, int n)
     static short cache[BUF_FRAMES*2];
     dsp_run(delay->in, cache, n);
 
-    for (int i = 0; i < n*2; i++) {
+    for (int i = 0; i < n*CHANNELS; i++) {
         cbuf_push(&delay->buf, cache[i] / 2);
         buf[i] = cache[i] + cbuf_shift(&delay->buf);
     }

source/engine/dsp.h

@@ -16,6 +16,37 @@ struct dsp_filter {
     void *data;
 };
 
+struct dsp_iir {
+    float freq;
+    int poles;
+    int n;  // Amount of constants
+    int order;  // How many times it's applied
+    float *ccof;
+    float *dcof;
+    float *dx;
+    float *dy;
+
+    struct dsp_filter in;
+};
+
+struct dsp_fir {
+    float freq;
+    int n;
+    int head;
+    float *cof;
+    float *dx;
+
+    struct dsp_filter in;
+};
+
+struct dsp_filter lp_fir_make(float freq);
+
+void dsp_iir_fillbuf(struct dsp_iir *iir, short *out, int n);
+struct dsp_filter hpf_make(int poles, float freq);
+struct dsp_filter lpf_make(int poles, float freq);
+struct dsp_filter bpf_make(int poles, float freq1, float freq2);
+struct dsp_filter npf_make(int poles, float freq1, float freq2);
+
 struct dsp_delay {
     unsigned int ms_delay;
     struct circbuf buf;
@@ -40,13 +71,7 @@ struct dsp_limiter {
 
 };
 
-struct dsp_hpf {
 
-};
-
-struct dsp_lpf {
-
-};
 
 struct phasor {
     unsigned int sr;
@@ -74,6 +99,9 @@ struct wav gen_square(float amp, float freq, int sr, int ch);
 struct wav gen_triangle(float amp, float freq, int sr, int ch);
 struct wav gen_saw(float amp, float freq, int sr, int ch);
 
+void gen_whitenoise(void *data, short *out, int n);
+void gen_pinknoise(void *data, short *out, int n);
+
 
 float sin_phasor(float p);
 float square_phasor(float p);

source/engine/iir.h

@@ -0,0 +1,48 @@
+#ifndef IIR_H
+#define IIR_H
+
+double *binomial_mult( int n, double *p );
+double *trinomial_mult( int n, double *b, double *c );
+
+double *dcof_bwlp( int n, double fcf );
+double *dcof_bwhp( int n, double fcf );
+double *dcof_bwbp( int n, double f1f, double f2f );
+double *dcof_bwbs( int n, double f1f, double f2f );
+
+int *ccof_bwlp( int n );
+int *ccof_bwhp( int n );
+int *ccof_bwbp( int n );
+double *ccof_bwbs( int n, double f1f, double f2f );
+
+double sf_bwlp( int n, double fcf );
+double sf_bwhp( int n, double fcf );
+double sf_bwbp( int n, double f1f, double f2f );
+double sf_bwbs( int n, double f1f, double f2f );
+
+float *fir_lp(int n, double fcf);
+float *fir_hp(int n, double fcf);
+float *fir_bpf(int n, double fcf1, double fcf2);
+
+struct dsp_iir bqlp_dcof(double fcf, float Q);
+struct dsp_iir bqhp_dcof(double fcf, float Q);
+struct dsp_iir bqbpq_dcof(double fcf, float Q);
+struct dsp_iir bqbp_dcof(double fcf, float Q);
+struct dsp_iir bqnotch_dcof(double fcf, float Q);
+struct dsp_iir bqapf_dcof(double fcf, float Q);
+struct dsp_iir bqpeq_dcof(double fcf, float Q, float dbgain);
+struct dsp_iir bqls_dcof(double fcf, float Q, float dbgain);
+struct dsp_iir bqhs_dcof(double fcf, float Q, float dbgain);
+
+struct dsp_iir p2_bwlp(double fcf);
+struct dsp_iir p2_bwhp(double fcf);
+struct dsp_iir p2_cdlp(double fcf);
+struct dsp_iir p2_cdhp(double fcf);
+struct dsp_iir p2_beslp(double fcf);
+struct dsp_iir p2_beshp(double fcf);
+
+struct dsp_iir che_lp(int order, double fcf, double e);
+struct dsp_iir che_hp(int order, double fcf, double e);
+struct dsp_iir che_bp(int order, double fcf1, double fcf2, double e);
+struct dsp_iir che_notch(int order, double fcf1, double fcf2, double e);
+
+#endif

source/engine/sound.c

@@ -177,7 +177,10 @@ void sound_init()
     del_filter.data = &dspdel;
 
     //first_free_bus(s600);
-    first_free_bus(del_filter);
+
+    struct dsp_filter wn;
+    wn.filter = gen_pinknoise;
+    //first_free_bus(wn);
 
 /*
     if (!drmp3_init_file(&mp3, "sounds/circus.mp3", NULL)) {
@@ -366,8 +369,9 @@ struct soundstream soundstream_make()
 void soundstream_fillbuf(struct soundstream *s, short *buf, int n)
 {
     int max = s->buf.write - s->buf.read;
-    for (int i = 0; i < n*CHANNELS; i++) {
-        buf[i] = (i < max) ? cbuf_shift(&s->buf) : 0;
+    int lim = (max < n*CHANNELS) ? max : n*CHANNELS;
+    for (int i = 0; i < lim; i++) {
+        buf[i] = cbuf_shift(&s->buf);
     }
 }