X-Git-Url: https://harrygodden.com/git/?a=blobdiff_plain;f=audio.h;h=448906be07e9af05c101b3c07766578dc7612f4d;hb=refs%2Fheads%2Frigidbody;hp=0d025c8195e75ef7159dcf5fb7f7371b97c87092;hpb=4fe3835ea66a7c1f775ba1fb36a33c0c5496d2f5;p=carveJwlIkooP6JGAAIwe30JlM.git

diff --git a/audio.h b/audio.h
index 0d025c8..448906b 100644
--- a/audio.h
+++ b/audio.h
@@ -147,6 +147,51 @@ audio_clip audio_challenge[] = {
    { .path = "sound/objective_fail.ogg" }
 };
 
+struct air_synth_data {
+   f32 speed;
+
+   /* internal */
+   f32 t;
+   struct dsp_biquad lpf;
+   SDL_SpinLock sl;
+}
+static air_data;
+
+static void audio_air_synth_get_samples( void *_data, f32 *buf, u32 count ){
+   struct air_synth_data *data = _data;
+
+   SDL_AtomicLock( &data->sl );
+   f32 spd = data->speed;
+   SDL_AtomicUnlock( &data->sl );
+
+   f32 s0  = sinf(data->t*2.0f),
+       s1  = sinf(data->t*0.43f),
+       s2  = sinf(data->t*1.333f),
+       sm  = vg_clampf( data->speed / 45.0f, 0, 1 ),
+       ft  = (s0*s1*s2)*0.5f+0.5f,
+       f   = vg_lerpf( 200.0f, 1200.0f, sm*0.7f + ft*0.3f ),
+       vol = 0.25f * sm;
+
+   dsp_init_biquad_butterworth_lpf( &data->lpf, f );
+
+   for( u32 i=0; i<count; i ++ ){
+      f32 v = (vg_randf64(&vg_dsp.rand) * 2.0f - 1.0f) * vol;
+      v = dsp_biquad_process( &data->lpf, v );
+
+      buf[i*2+0] = v;
+      buf[i*2+1] = v;
+   }
+
+   data->t += (f32)(count)/44100.0f;
+};
+
+static audio_clip air_synth = {
+   .flags = k_audio_format_gen,
+   .size = 0,
+   .func = audio_air_synth_get_samples,
+   .data = &air_data
+};
+
 static void audio_init(void)
 {
    audio_clip_loadn( audio_board, vg_list_size(audio_board), NULL );
@@ -175,6 +220,11 @@ static void audio_init(void)
    audio_lock();
    audio_set_lfo_wave( 0, k_lfo_polynomial_bipolar, 80.0f );
    audio_set_lfo_frequency( 0, 20.0f );
+
+   skaterift.aud_air = audio_get_first_idle_channel();
+   if( skaterift.aud_air ) 
+      audio_channel_init( skaterift.aud_air, &air_synth, 0 );
+
    audio_unlock();
 }
 
@@ -224,12 +274,13 @@ static void audio_ambient_sprites_update( world_instance *world, v3f co )
    
    if( sprite_type != k_audio_sprite_type_none ){
       if( sprite_type == k_audio_sprite_type_grass ){
-         audio_ambient_sprite_play( sprite_pos, &audio_grass[vg_randu32()%4] );
+         audio_ambient_sprite_play( sprite_pos, 
+                                    &audio_grass[vg_randu32(&vg.rand)%4] );
       }
       else if( sprite_type == k_audio_sprite_type_water ){
          if( world->water.enabled ){
             audio_ambient_sprite_play( sprite_pos, 
-                                       &audio_water[vg_randu32()%6] );
+                                       &audio_water[vg_randu32(&vg.rand)%6] );
          }
       }
    }