X-Git-Url: https://harrygodden.com/git/?p=vg.git;a=blobdiff_plain;f=vg_audio_dsp.c;fp=vg_audio_dsp.c;h=3714e32e2b5dac58b5895f2476f2ff1e7fe3a899;hp=0000000000000000000000000000000000000000;hb=3b14f3dcd5bf9dd3c85144f2123d667bfa4bb63f;hpb=fce86711735b15bff37de0f70716808410fcf269

diff --git a/vg_audio_dsp.c b/vg_audio_dsp.c
new file mode 100644
index 0000000..3714e32
--- /dev/null
+++ b/vg_audio_dsp.c
@@ -0,0 +1,298 @@
+#include "vg_audio_dsp.h"
+#include "vg_mem.h"
+#include "vg_async.h"
+
+struct vg_dsp vg_dsp;
+
+float *dsp_allocate( u32 samples )
+{
+   samples = vg_align4( samples );
+
+   if( vg_dsp.allocations + samples > (1024*1024)/4 )
+      vg_fatal_error( "too much dsp" );
+
+   float *buf = &vg_dsp.buffer[ vg_dsp.allocations ];
+   vg_dsp.allocations += samples;
+
+   return buf;
+}
+
+
+/*
+ * filters
+ * ----------------------------------------------
+ */
+
+f32 dsp_biquad_process( struct dsp_biquad *bq, f32 xn ){
+   f32 yn = + bq->a0*xn + bq->a1*bq->xnz1 + bq->a2*bq->xnz2 
+            - bq->b1*bq->ynz1 - bq->b2*bq->ynz2;
+   bq->xnz2 = bq->xnz1;
+   bq->xnz1 = xn;
+   bq->ynz2 = bq->ynz1;
+   bq->ynz1 = yn;
+   return yn + bq->offset;
+}
+
+void dsp_init_biquad_butterworth_lpf( struct dsp_biquad *bq, f32 fc ){
+   f32 c = 1.0f/tanf(VG_PIf*fc / 44100.0f);
+   bq->a0 = 1.0f / (1.0f + sqrtf(2.0f)*c + powf(c, 2.0f) );
+   bq->a1 = 2.0f * bq->a0;
+   bq->a2 = bq->a0;
+   bq->b1 = 2.0f * bq->a0*(1.0f - powf(c, 2.0f));
+   bq->b2 = bq->a0 * (1.0f - sqrtf(2.0f)*c + powf(c, 2.0f) );
+}
+
+void dsp_read_delay( struct dsp_delay *delay, float *s, u32 t ){
+   u32 index = delay->cur+t;
+
+   if( index >= delay->length )
+      index -= delay->length;
+
+   *s = delay->buffer[ index ];
+}
+
+void dsp_write_delay( struct dsp_delay *delay, float *s )
+{
+   u32 index = delay->cur;
+   delay->buffer[ index ] = *s;
+
+   delay->cur ++;
+
+   if( delay->cur >= delay->length )
+      delay->cur = 0;
+}
+
+void dsp_init_delay( struct dsp_delay *delay, float length )
+{
+   delay->length = 44100.0f * length;
+   delay->cur = 0;
+   delay->buffer = dsp_allocate( delay->length );
+
+   for( int i=0; i<delay->length; i++ )
+      delay->buffer[i] = 0.0f;
+}
+
+void dsp_update_lpf( struct dsp_lpf *lpf, float freq )
+{
+   lpf->exponent = 1.0f-expf( -(1.0f/44100.0f) * 2.0f * VG_PIf * freq );
+}
+
+void dsp_init_lpf( struct dsp_lpf *lpf, float freq )
+{
+   lpf->buffer = dsp_allocate( 4 );
+   lpf->buffer[0] = 0.0f;
+   dsp_update_lpf( lpf, freq );
+}
+
+void dsp_write_lpf( struct dsp_lpf *lpf, float *s )
+{
+   float diff = *s - lpf->buffer[0];
+   lpf->buffer[0] += diff * lpf->exponent;
+}
+
+void dsp_read_lpf( struct dsp_lpf *lpf, float *s )
+{
+   *s = lpf->buffer[0];
+}
+
+void dsp_init_schroeder( struct dsp_schroeder *sch, float length, float gain )
+{
+   dsp_init_delay( &sch->M, length );
+   sch->gain = gain;
+}
+
+void dsp_process_schroeder( struct dsp_schroeder *sch,
+                            float *input, float *output )
+{
+   float dry = *input;
+
+   float delay_output;
+   dsp_read_delay( &sch->M, &delay_output, 1 );
+
+   float feedback_attenuated = delay_output * sch->gain,
+         input_feedback_sum  = dry + feedback_attenuated;
+
+   dsp_write_delay( &sch->M, &input_feedback_sum );
+
+   *output = delay_output - input_feedback_sum*sch->gain;
+}
+
+/* temporary global design */
+static struct dsp_lpf __lpf_mud_free;
+static struct dsp_delay __echos[8];
+
+#ifdef VG_ECHO_LPF_BUTTERWORTH
+static struct dsp_biquad __echos_lpf[8];
+#else
+static struct dsp_lpf   __echos_lpf[8];
+#endif
+static struct dsp_schroeder __diffusion_chain[8];
+
+static void async_vg_dsp_alloc_texture( void *payload, u32 size )
+{
+   glGenTextures( 1, &vg_dsp.view_texture );
+   glBindTexture( GL_TEXTURE_2D, vg_dsp.view_texture );
+   glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, 
+                 GL_RGBA, GL_UNSIGNED_BYTE, vg_dsp.view_texture_buffer );
+   glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
+   glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
+}
+
+void vg_dsp_init( void ){
+   vg_rand_seed( &vg_dsp.rand, 461 );
+   vg_dsp.buffer = vg_linear_alloc( vg_mem.rtmemory, 1024*1024*1 );
+   vg_dsp.view_texture_buffer = vg_linear_alloc( vg_mem.rtmemory, 512*512 );
+
+   vg_async_call( async_vg_dsp_alloc_texture, NULL, 0 );
+
+   /* temporary global design */
+   dsp_init_lpf( &__lpf_mud_free, 125.0f );
+
+   float sizes[] = 
+         { 2.0f, 4.0f, 8.0f, 16.0f,   32.0f, 64.0f, 128.0f, 256.0f };
+
+   float variance = 0.1f;
+
+   for( int i=0; i<8; i++ ){
+      float reflection_time = ((sizes[i])/343.0f) * 1000.0f;
+
+      float var   = 1.0f + (vg_randf64(&vg_dsp.rand)*2.0f - 1.0f) * variance,
+            total = reflection_time * var;
+
+      dsp_init_delay( &__echos[i], total / 1000.0f );
+
+      float freq = vg_lerpf( 800.0f, 350.0f, sizes[i] / 256.0f );
+
+#ifdef VG_ECHO_LPF_BUTTERWORTH
+      dsp_init_biquad_butterworth_lpf( &__echos_lpf[i], freq );
+#else
+      dsp_init_lpf( &__echos_lpf[i], freq );
+#endif
+   }
+
+   float diffusions[] = { 187.0f, 159.0f, 143.0f, 121.0f, 
+                          79.0f,  57.0f,  27.0f,  11.0f };
+
+   for( int i=0; i<8; i++ ){
+      dsp_init_schroeder( __diffusion_chain+i, diffusions[i]/1000.0f, 0.7f );
+   }
+}
+
+void vg_dsp_process( float *stereo_in, float *stereo_out )
+{
+   float in_total = (stereo_in[0]+stereo_in[1])*0.5f;
+   float recieved = 0.0f;
+
+   for( int i=0; i<8; i++ ){
+      f32 echo;
+      dsp_read_delay(  __echos+i, &echo, 1 );
+
+#ifdef VG_ECHO_LPF_BUTTERWORTH
+      echo = dsp_biquad_process( __echos_lpf+i, echo );
+#else
+      dsp_write_lpf( __echos_lpf+i, &echo );
+      dsp_read_lpf(  __echos_lpf+i, &echo );
+#endif
+
+      recieved += echo * vg_dsp.echo_tunings[i]*0.98;
+   }
+
+   float diffused = recieved;
+
+   for( int i=0; i<8; i++ ){
+      dsp_process_schroeder( __diffusion_chain+i, &diffused, &diffused );
+   }
+
+   float diffuse_mix = vg_dsp.reverb_wet_mix;
+         diffuse_mix = vg_lerpf( recieved, diffused, diffuse_mix );
+   float total = in_total + diffuse_mix;
+
+   float low_mud;
+   dsp_write_lpf( &__lpf_mud_free, &total );
+   dsp_read_lpf(  &__lpf_mud_free, &low_mud );
+
+   total -= low_mud;
+
+   for( int i=0; i<8; i++ )
+      dsp_write_delay( __echos+i, &total );
+
+   stereo_out[0]  = stereo_in[0]*vg_dsp.reverb_dry_mix;
+   stereo_out[1]  = stereo_in[1]*vg_dsp.reverb_dry_mix;
+   stereo_out[0] += diffuse_mix*2.0f*vg_dsp.reverb_wet_mix;
+   stereo_out[1] += diffuse_mix*2.0f*vg_dsp.reverb_wet_mix;
+}
+
+void dsp_update_tunings(void)
+{
+   float sizes[] = 
+         { 2.0f, 4.0f, 8.0f, 16.0f,   32.0f, 64.0f, 128.0f, 256.0f };
+   float volumes[] = 
+         { 0.2f, 0.3f, 0.5f, 0.7f,   0.8f, 0.9f, 1.0f, 1.0f };
+
+   float avg_distance = 0.0f;
+
+   for( int i=0; i<8; i++ )
+      vg_dsp.echo_tunings[i] = 0.5f;
+
+   for( int j=0; j<14; j++ ){
+      float d = vg_dsp.echo_distances[j];
+      
+      for( int i=0; i<7; i++ ){
+         if( d < sizes[i+1] ){
+            float range = sizes[i+1]-sizes[i];
+            float t = vg_clampf( (d - sizes[i])/range, 0.0f, 1.0f );
+
+            vg_dsp.echo_tunings[i  ] += 1.0f-t;
+            vg_dsp.echo_tunings[i+1] += t;
+
+            break;
+         }
+      }
+
+      avg_distance += d;
+   }
+   avg_distance /= 14.0f;
+   
+
+   vg_dsp.reverb_wet_mix =1.0f-vg_clampf((avg_distance-30.0f)/200.0f,0.0f,1.0f);
+   vg_dsp.reverb_dry_mix =1.0f-vg_dsp.reverb_wet_mix*0.4f;
+
+   float total = 0.0f;
+   for( int i=0; i<8; i++ )
+      total += vg_dsp.echo_tunings[i];
+
+   if( total > 0.0f ){
+      float inverse = 1.0f/total;
+
+      for( int i=0;i<8; i++ ){
+         vg_dsp.echo_tunings[i] *= inverse;
+      }
+   }
+
+   for( int i=0; i<8; i++ ){
+      float freq = vg_lerpf( 200.0f, 500.0f, vg_dsp.echo_tunings[i] );
+
+#ifdef VG_ECHO_LPF_BUTTERWORTH
+      dsp_init_biquad_butterworth_lpf( &__echos_lpf[i], freq );
+#else
+      dsp_update_lpf( &__echos_lpf[i], freq );
+#endif
+   }
+
+   for( int i=0;i<8; i++ ){
+      vg_dsp.echo_tunings[i] *= volumes[i];
+   }
+}
+
+void vg_dsp_free( void )
+{
+   glDeleteTextures( 1, &vg_dsp.view_texture );
+}
+
+void vg_dsp_update_texture( void )
+{
+   for( int i=0; i<512*512; i++ ){
+      float v = vg_clampf( vg_dsp.buffer[i] * 0.5f + 0.5f, 0.0f, 1.0f );
+      vg_dsp.view_texture_buffer[i] = v * 255.0f;
+   }
+}