From c03d395f6848fe9b2d1185173a9cf5ec8277394f Mon Sep 17 00:00:00 2001
From: gramanas <anastasis.gramm2@gmail.com>
Date: Tue, 21 Nov 2023 14:07:33 +0200
Subject: Crappy fft for spectrum analysis and initial gtk test

---
 src/synth_engine.c | 62 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 51 insertions(+), 11 deletions(-)

(limited to 'src/synth_engine.c')

diff --git a/src/synth_engine.c b/src/synth_engine.c
index 517f9d8..b47d510 100644
--- a/src/synth_engine.c
+++ b/src/synth_engine.c
@@ -167,8 +167,9 @@ make_sample(void *synthData, unsigned int sample_rate, int frame)
 
   // if rms == 0 we can deduce there are no notes however notes_active handles
   // stopping any already playing notes and if we remove it we need to make
-  // sure that notes stop some other way (it laso happens every frame)
-  rms = sqrt(rms / n);
+  // sure that notes stop some other way (it also happens every frame)
+  rms = sqrt(rms / (float)n);
+  //  printf("rms %f\n", rms);
 
   for (int i = 0; i < MIDI_NOTES; i++) {
     if (!synth->midi_note[i].active)
@@ -195,7 +196,7 @@ make_sample(void *synthData, unsigned int sample_rate, int frame)
                                                  synth->x,
                                                  sample_rate);
 
-    sample += rms * adsr * synth_sample;
+    sample += synth->midi_note[i].velocity * adsr * synth_sample;
   }
 
   /* filter */
@@ -233,6 +234,16 @@ add_to_viz(synth_t *synth, float sample)
   }
 }
 
+void
+add_to_fftviz(synth_t *synth, float sample)
+{
+  synth->fftviz.wave[synth->fftviz.wi++] = sample;
+
+  if (synth->fftviz.wi >= VIZ_BUF) {
+    synth->fftviz.wi = 0;
+  }
+}
+
 void
 add_to_delay(synth_t *synth, float sample)
 {
@@ -304,7 +315,30 @@ get_frame(void *outputBuffer, synth_t *synth, int i)
 #include "fftw3.h"
 
 int
-process(float * buffer)
+get_spectrum(synth_t * synth, float * buffer)
+{
+  int fft_output_len = FRAMES_PER_BUFFER / 2 + 1;
+  float input[FRAMES_PER_BUFFER];
+
+  for( unsigned long i=0; i < FRAMES_PER_BUFFER * 2; i += 2 ) {
+    input[i / 2] = buffer[i];
+  }  
+  fftwf_complex* output = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fft_output_len);
+    
+  fftwf_plan forward_plan = fftwf_plan_dft_r2c_1d(fft_output_len, input, output, FFTW_ESTIMATE);
+
+  fftwf_execute(forward_plan);
+
+  for (int i=0; i < fft_output_len - 2*fft_output_len/3; i++ ) {
+    add_to_fftviz(synth, sqrt(output[i][0] * output[i][0] + output[i][1] * output[i][1]));
+  }
+
+  fftwf_destroy_plan(forward_plan);
+  fftwf_free(output);
+}
+
+int
+process(synth_t * synth, float * buffer)
 {
   int len = FRAMES_PER_BUFFER;
 
@@ -322,6 +356,8 @@ process(float * buffer)
 
   fftwf_execute(forward_plan);
 
+  // cont:
+  /* printf("ASDASD!!!\n"); */
   /* for (int i=0; i < (len / 2 + 1); i++ ) { */
   /*   if (frequency_signal[i][0] > 1) { */
   /*     frequency_signal[i][0] = 0; */
@@ -329,15 +365,16 @@ process(float * buffer)
   /*   if (frequency_signal[i][1] > 1) { */
   /*     frequency_signal[i][1] = 0; */
   /*   } */
-  /*      printf("%f %f | ", sqrt(frequency_signal[i][0] * frequency_signal[i][0] + frequency_signal[i][1] * frequency_signal[i][1]), atan2(frequency_signal[i][1], frequency_signal[i][0])); */
+  /*   printf("%f %f | \n", sqrt(frequency_signal[i][0] * frequency_signal[i][0] + frequency_signal[i][1] * frequency_signal[i][1]), atan2(frequency_signal[i][1], frequency_signal[i][0])); */
 
-  /*   float f = atan2(frequency_signal[i][1], frequency_signal[i][0]); */
-  /*   if (f > M_PI / 2 && f < 2 * M_PI / 3) { */
-  /*     frequency_signal[i][0] = 0.0; */
-  /*     frequency_signal[i][1] = 0.0; */
-  /*   } */
+  /*   /\* float f = atan2(frequency_signal[i][1], frequency_signal[i][0]); *\/ */
+  /*   /\* if (f > M_PI / 2 && f < 2 * M_PI / 3) { *\/ */
+  /*   /\*   frequency_signal[i][0] = 0.0; *\/ */
+  /*   /\*   frequency_signal[i][1] = 0.0; *\/ */
+  /*   /\* } *\/ */
   /* } */
 
+  /* printf("ASDASD!!!\n"); */
   fftwf_execute(backward_plan);
 
   for (unsigned long i=0; i < len * 2; i += 2) {
@@ -401,7 +438,8 @@ sound_gen(const void *inputBuffer, void *outputBuffer,
     get_frame(buffer, synth, i);
   }
   // process buffer
-  //if (synth->multi) process(buffer);
+  // process(synth, buffer);
+  get_spectrum(synth, buffer);
 
   // output buffer
   for( unsigned long i=0; i<framesPerBuffer * 2; i += 2 ) {
@@ -481,6 +519,8 @@ init_synth(synth_t * synth)
   
   synth->viz.sample_rate_divider = 1;
   synth->viz.wi = 0;
+  synth->fftviz.sample_rate_divider = 1;
+  synth->fftviz.wi = 0;
 
   lpf_init();
   synth->fff = create_bw_low_pass_filter(2, SAMPLE_RATE, 400);
-- 
cgit v1.2.3