delay.c

@@ -44,8 +44,8 @@ void delay_process(
     for( size_t i = 0; i < frame_size; ++i ) {
         if( delay->duration > 0 ) {
             out[i] =
-                in[i]
+                0.5 * in[i]
-                + delay->mix * delay->buf[ delay->buf_idx ];
+                + 0.5 * delay->mix * delay->buf[ delay->buf_idx ];
 
             delay->buf[ delay->buf_idx ] *= delay->feedback;
             delay->buf[ delay->buf_idx ] += (1.0 - delay->feedback) * in[i];

guitfx.c

@@ -14,9 +14,7 @@
 #include <pipewire/filter.h>
 
 #include "delay.h"
-#include "sust.h"
 
-float envelope( float x );
 struct data;
 
 struct port {
@@ -33,9 +31,6 @@ struct data {
 	//! effect data
 	uint64_t last_tap;
 	struct delay delay;
-	struct sust sust;
-
-        unsigned prog;
 
 	//! elapsed time in number of samples
 	uint64_t time;
@@ -89,49 +84,26 @@ static void on_process(void *userdata, struct spa_io_position *position)
 									    // expr pedal
 										float val_f = ((float)midi_data[2]) / 128.0;
 										printf("Expr Pedal %f\n", val_f);
-										if ( val_f > 0.1 ) {
+
 										data->delay.mix = val_f;
-										} else {
-										  data->delay.mix = 0.0;
-										}
 									    break;
 
 								    case 0x42:
 										// sust pedal
-								      if( data->prog == 1 ) {
-										if( midi_data[2] >= 64) {
-											sust_swap( &data->sust );
-										    data->sust.playing = true;
 
-											data->sust.start_idx = data->sust.idx;
-											data->sust.idx = 0;
-										} else {
-											data->sust.playing = false;
-										}
-								      }
-
-										// tap tempo
-										if( data->prog == 0 ) {
    									    uint64_t cur_tap = frame + c->offset;
     									uint64_t duration = cur_tap - data->last_tap;
     									data->last_tap = cur_tap;
     									if( duration < (4*position->clock.rate.denom) ) {
-										    delay_set_time( &data->delay, duration );
+    									  delay_set_time( &data->delay, duration/4 );
     									}
-
-
-										  sust_resize( &data->sust, duration );
-										}
-
 										break;
 								}
-
 								break;
 
 							case 0xc0:
 							    // program change
 								printf("program change: %u\n", midi_data[1]);
-								data->prog = midi_data[1];
 							    break;
 						}
 					} else {
@@ -152,11 +124,9 @@ static void on_process(void *userdata, struct spa_io_position *position)
 
 
 	float * const in = pw_filter_get_dsp_buffer(data->guit_in_port, n_samples);
-	float tmp[n_samples];
 	float * out = pw_filter_get_dsp_buffer(data->out_port, n_samples);
 	if( in && out ) {
-	  sust_process( &data->sust, n_samples, in, tmp );
+        delay_process( &data->delay, n_samples, in, out );
-	  delay_process( &data->delay, n_samples, tmp, out );
 	}
 }
 
@@ -176,8 +146,6 @@ int main(int argc, char *argv[])
 	struct data data = { 0, };
 
 	delay_init( &data.delay );
-	sust_init( &data.sust );
-	data.prog = 0;
 
 	const struct spa_pod *params[1];
 	uint8_t buffer[1024];

meson.build

@@ -1,13 +1,8 @@
 project('guitfx', 'c')
 pipewire_dep = dependency('libpipewire-0.3')
-
-cc = meson.get_compiler('c')
-m_dep = cc.find_library('m', required : false)
-
 executable(
     'guitfx',
     'guitfx.c',
     'delay.c',
-    'sust.c',
+    dependencies : [pipewire_dep],
-    dependencies : [pipewire_dep, m_dep],
 )

sust.c

@@ -1,87 +0,0 @@
-#include "sust.h"
-#include <math.h>
-#include <stdlib.h>
-#include <stdio.h>
-
-void sust_init( struct sust * sust ) {
-    sust->mode = MODE_Sostenuto;
-
-    sust->playing = false;
-
-    sust->start_idx = 0;
-    sust->idx = 0;
-
-    sust->buf_len = 51200;
-    sust->record_buf = malloc( sizeof(float) * sust->buf_len );
-    sust->play_buf = malloc( sizeof(float) * sust->buf_len );
-}
-
-float envelope( float x ) {
-    if( x < 0.4 )
-        return (x / 0.4) * (x / 0.4);
-    if( x < 0.6 )
-        return 1.0;
-
-   float v  = 1.0 - ((x - 0.6) / 0.4);
-   return v*v;
-}
-
-float softcos( float x ) {
-    return sin( x * (3.141 / 2.0) );
-}
-
-void sust_resize( struct sust * sust, size_t new_len ) {
-  sust->buf_len = new_len;
-  sust->play_buf = realloc( sust->play_buf, sizeof(float) * new_len );
-  sust->record_buf = realloc( sust->record_buf, sizeof(float) * new_len );
-  sust->idx %= new_len;
-}
-
-void sust_swap(
-    struct sust * sust
-) {
-    float * tmp = sust->play_buf;
-    sust->play_buf = sust->record_buf;
-    sust->record_buf = tmp;
-
-    for( int i = 0; i  < sust->buf_len; ++i ) {
-        sust->record_buf[i] = sust->play_buf[i];
-    }
-}
-
-void sust_process(
-    struct sust * sust,
-    size_t frame_size,
-    float const * in,
-    float * out
-) {
-    for( size_t i = 0; i < frame_size; ++i ) {
-
-        if( sust->mode == MODE_Sustain && sust->idx == 0 ) {
-            sust_swap( sust );
-        }
-
-        float out_value = in[i];
-
-        if( sust->playing ) {
-            int n_voices = 5;
-
-            for( int v = 0; v < n_voices; ++v ) {
-                size_t play_idx = (sust->start_idx + sust->idx + ((v*sust->buf_len)/n_voices)) % sust->buf_len;
-                float gain = envelope( ((float) play_idx) / ((float)sust->buf_len) );
-               //printf("gain = %f\n", gain);
-                out_value += 0.5 *gain * sust->play_buf[ play_idx ];
-            }
-        }
-
-        if( sust->mode == MODE_Sostenuto ) {
-            sust->record_buf[ sust->idx ] = in[i];
-        }
-        if( sust->mode == MODE_Sustain ) {
-            sust->record_buf[ sust->idx ] = 0.5*out_value;
-        }
-
-        sust->idx = (sust->idx + 1) % sust->buf_len;
-        out[i] = out_value;
-    }
-}

sust.h

@@ -1,32 +0,0 @@
-#pragma once
-
-#include <stdbool.h>
-#include <stddef.h>
-
-enum sust_mode {
-    MODE_Sustain = 0,
-    MODE_Sostenuto = 1
-};
-
-struct sust {
-    enum sust_mode mode;
-    bool playing;
-
-    size_t start_idx;
-    size_t idx;
-    size_t buf_len;
-    float * record_buf;
-    float * play_buf;
-};
-
-
-void sust_init( struct sust * sust );
-void sust_resize( struct sust * sust, size_t new_len );
-void sust_swap( struct sust * sust );
-
-void sust_process(
-    struct sust * sust,
-    size_t frame_size,
-    float const * in,
-    float * out
-);