shithub: soundpipe

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added fftcut

--- a/h/ftbl.h

+++ b/h/ftbl.h

@@ -17,3 +17,4 @@

 void sp_gen_triangle(sp_data *sp, sp_ftbl *ft);

 void sp_gen_composite(sp_data *sp, sp_ftbl *ft, const char *argstring);

 void sp_gen_sinesum(sp_data *sp, sp_ftbl *ft, const char *argstring);

+void sp_ftbl_fftcut(sp_ftbl *ft, int cut);

--- a/modules/ftbl.c

+++ b/modules/ftbl.c

@@ -6,6 +6,7 @@

 #include <sndfile.h>

 #endif

 #include "soundpipe.h"

+#include "kiss_fftr.h"

 #ifndef M_PI

 #define M_PI 3.14159265358979323846

@@ -178,4 +179,34 @@

         }

     }

     sp_ftbl_destroy(&args);

+}

+

+void sp_ftbl_fftcut(sp_ftbl *ft, int cut)

+{

+    kiss_fftr_cfg fft, ifft;

+    kiss_fft_cpx *tmp;

+    int i;

+    SPFLOAT scale;

+

+    fft = kiss_fftr_alloc(ft->size, 0, NULL, NULL);

+    ifft = kiss_fftr_alloc(ft->size, 1, NULL, NULL);

+    tmp = malloc(sizeof(kiss_fft_cpx) * ft->size);

+

+    kiss_fftr(fft, ft->tbl, tmp);

+

+    for (i = cut; i < (ft->size / 2); i++) {

+        tmp[i].r = 0;

+        tmp[i].i = 0;

+    }

+

+    kiss_fftri(ifft, tmp, ft->tbl);

+

+    scale = 1.0 / ft->size;

+    for (i = 0; i < ft->size; i++) {

+        ft->tbl[i] *= scale;

+    }

+

+    free(tmp);

+    kiss_fftr_free(fft);

+    kiss_fftr_free(ifft);

 }