waveguide_nl.h

Go to the documentation of this file.

#ifndef WAVEGUIDE_NL_H
#define WAVEGUIDE_NL_H
 
#include <stdlib.h>
#include <string.h>
 
typedef struct {
        int size;
        float *buffer[2];
        int ptr;
        int delay;
        float fc;
        float lp[2];
        float a1a;
        float a1b;
        float zm1[2];
} waveguide_nl;
 
waveguide_nl *waveguide_nl_new(int size, float fc, float da, float db)
{
        waveguide_nl *wg = malloc(sizeof(waveguide_nl));
        wg->size = size;
        wg->delay = size;
        wg->buffer[0] = calloc(size, sizeof(float));
        wg->buffer[1] = calloc(size, sizeof(float));
        wg->ptr = 0;
        wg->fc = fc;
        wg->lp[0] = 0.0f;
        wg->lp[1] = 0.0f;
        wg->zm1[0] = 0.0f;
        wg->zm1[1] = 0.0f;
        wg->a1a = (1.0f - da) / (1.0f + da);
        wg->a1b = (1.0f - db) / (1.0f + db);
 
        return wg;
}
 
void waveguide_nl_reset(waveguide_nl *wg)
{
        memset(wg->buffer[0], 0, wg->size * sizeof(float));
        memset(wg->buffer[1], 0, wg->size * sizeof(float));
        wg->lp[0] = 0.0f;
        wg->lp[1] = 0.0f;
        wg->zm1[0] = 0.0f;
        wg->zm1[1] = 0.0f;
}
 
void waveguide_nl_free(waveguide_nl *wg)
{
        if (!wg) {
                return;
        }
        free(wg->buffer[0]);
        free(wg->buffer[1]);
        free(wg);
}
 
void waveguide_nl_set_delay(waveguide_nl *wg, int delay)
{
        if (delay > wg->size) {
                wg->delay = wg->size;
        } else if (delay < 1) {
                wg->delay = 1;
        } else {
                wg->delay = delay;
        }
}
 
void waveguide_nl_set_fc(waveguide_nl *wg, float fc)
{
        wg->fc = fc;
}
 
void waveguide_nl_set_ap(waveguide_nl *wg, float da, float db)
{
        wg->a1a = (1.0f - da) / (1.0f + da);
        wg->a1b = (1.0f - db) / (1.0f + db);
}
 
void waveguide_nl_process_lin(waveguide_nl *wg, float in0, float in1, float *out0, float *out1)
{
        float tmp;
 
        *out0 = wg->buffer[0][(wg->ptr + wg->delay) % wg->size];
        *out0 = wg->lp[0] * (wg->fc - 1.0f) + wg->fc * *out0;
        wg->lp[0] = *out0;
        tmp = *out0 * -(wg->a1a) + wg->zm1[0];
        wg->zm1[0] = tmp * wg->a1a + *out0;
        *out0 = tmp;
 
        *out1 = wg->buffer[1][(wg->ptr + wg->delay) % wg->size];
        *out1 = wg->lp[1] * (wg->fc - 1.0f) + wg->fc * *out1;
        wg->lp[1] = *out1;
        tmp = *out1 * -(wg->a1a) + wg->zm1[1];
        wg->zm1[1] = tmp * wg->a1a + *out1;
        *out1 = tmp;
 
        wg->buffer[0][wg->ptr] = in0;
        wg->buffer[1][wg->ptr] = in1;
        wg->ptr--;
        if (wg->ptr < 0) {
                wg->ptr += wg->size;
        }
}
 
void waveguide_nl_process(waveguide_nl *wg, float in0, float in1, float *out0, float *out1)
{
        float tmp;
        float a1;
        float b;
 
        *out0 = wg->buffer[0][(wg->ptr + wg->delay) % wg->size];
        *out0 = wg->lp[0] * (wg->fc - 1.0f) + wg->fc * *out0;
        wg->lp[0] = *out0;
        b = (*out0 + 1.0) * 6.0f;
        if (b > 1.0f) {
                b = 1.0f;
        } 
        
        if (b < 0.0f) {
                b = 0.0f;
        }
        a1 = b * wg->a1a + (1.0f - b) * wg->a1b;
        tmp = *out0 * -a1 + wg->zm1[0];
        wg->zm1[0] = tmp * a1 + *out0;
        *out0 = tmp;
 
        *out1 = wg->buffer[1][(wg->ptr + wg->delay) % wg->size];
        *out1 = wg->lp[1] * (wg->fc - 1.0f) + wg->fc * *out1;
        wg->lp[1] = *out1;
        b = (*out1 + 1.0) * 6.0f;
        if (b > 1.0f) {
                b = 1.0f;
        }
        
        if (b < 0.0f) {
                b = 0.0f;
        }
        a1 = b * wg->a1a + (1.0f - b) * wg->a1b;
        tmp = *out1 * -a1 + wg->zm1[1];
        wg->zm1[1] = tmp * a1 + *out1;
        *out1 = tmp;
 
        wg->buffer[0][wg->ptr] = in0;
        wg->buffer[1][wg->ptr] = in1;
        wg->ptr--;
        if (wg->ptr < 0) {
                wg->ptr += wg->size;
        }
}
 
#endif