Sampler crossfading

2 files changed, 101 insertions, 38 deletions

diff --git a/TODO b/TODO
index 7db1d98..d4ad698 100644
--- a/TODO
+++ b/TODO
@@ -12,7 +12,6 @@ To-Do list
   - Simple tonal synth
   - Kick, snare, cymbal
   - EQ, delay, reverb, compressor, limiter
-  - Sampler
   - Sample rendering
   - Internal sample rate for time values
 
@@ -58,6 +57,7 @@ Done
   - Sample loading
   - WAV import
   - Drag & drop audio files
+  - Sampler
 
 - UI
   - Piano roll
diff --git a/source/saw/main.c b/source/saw/main.c
index cc2bfa1..02d94c4 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -51,6 +51,8 @@
 //  Constants
 //
 
+#define TIME_EPS 0.0001
+
 enum {
   //  TODO
   //
@@ -187,8 +189,6 @@ typedef struct {
   f64            begin;
   f64            end;
   f64            tail;
-  f64            fade_in;
-  f64            fade_out;
   f64            crossfade;
   f64            base_frequency;
   f64            volume;
@@ -547,6 +547,9 @@ static void saw_audio_render(void) {
             case INSTRUMENT_SAMPLER: {
               saw_sampler_t *sam = &track->sampler;
 
+              if (sam->begin + sam->crossfade + TIME_EPS >= sam->end)
+                break;
+
               f64 frequency = saw_voices[n].frequency;
               f64 amplitude = saw_voices[n].amplitude;
 
@@ -561,14 +564,86 @@ static void saw_audio_render(void) {
                                                sustain, duration,
                                                release);
 
-              saw_playback_temp[i * CHANNEL_COUNT] +=
-                  (f32) (saw_sampler(sam, 0, frequency,
-                                     saw_voices[n].time) *
-                         a);
-              saw_playback_temp[i * CHANNEL_COUNT + 1] +=
-                  (f32) (saw_sampler(sam, 1, frequency,
-                                     saw_voices[n].time) *
-                         a);
+              f64 crossfade       = sam->crossfade;
+              f64 sample_begin    = sam->begin;
+              f64 sample_end      = sam->end;
+              f64 sample_duration = sample_end - sample_begin -
+                                    crossfade;
+              f64 sample_tail = sam->tail;
+              f64 body_end    = duration + crossfade;
+              f64 tail_begin  = duration;
+              f64 tail_end    = tail_begin + sample_tail;
+
+              if (t <= body_end) {
+                //  Play the body
+                //
+
+                f64 q = t;
+                assert(sample_duration > TIME_EPS);
+                while (q >= sample_duration)
+                  q -= sample_duration;
+                q += sample_begin;
+
+                f64 u0 = 1.;
+                if (t > tail_begin && crossfade > TIME_EPS)
+                  u0 = 1. - (t - tail_begin) / crossfade;
+
+                if (t >= sample_duration && q < crossfade &&
+                    crossfade > TIME_EPS) {
+                  //  Play the body crossfade
+                  //
+
+                  f64 u = u0 * (1. - q / crossfade);
+                  f64 r = sample_begin + sample_duration + q;
+                  i64 k = (i64) floor(r * SAMPLE_RATE + .5);
+
+                  saw_playback_temp[i * CHANNEL_COUNT] +=
+                      (f32) (saw_sampler(sam, 0, frequency, k) * a *
+                             u);
+                  saw_playback_temp[i * CHANNEL_COUNT + 1] +=
+                      (f32) (saw_sampler(sam, 1, frequency, k) * a *
+                             u);
+                }
+
+                {
+                  //  Play the body main part
+                  //
+
+                  f64 u = u0;
+                  if (t >= sample_duration && q < crossfade &&
+                      crossfade > TIME_EPS)
+                    u *= q / crossfade;
+
+                  f64 r = sample_begin + q;
+                  i64 k = (i64) floor(r * SAMPLE_RATE + .5);
+
+                  saw_playback_temp[i * CHANNEL_COUNT] +=
+                      (f32) (saw_sampler(sam, 0, frequency, k) * a *
+                             u);
+                  saw_playback_temp[i * CHANNEL_COUNT + 1] +=
+                      (f32) (saw_sampler(sam, 1, frequency, k) * a *
+                             u);
+                }
+              }
+
+              if (t >= tail_begin && t <= tail_end) {
+                //  Play the tail
+                //
+
+                f64 q = t - tail_begin;
+
+                f64 u = 1.;
+                if (q < crossfade && crossfade > TIME_EPS)
+                  u = q / crossfade;
+
+                f64 r = sample_end + q;
+                i64 k = (i64) floor(r * SAMPLE_RATE + .5);
+
+                saw_playback_temp[i * CHANNEL_COUNT] +=
+                    (f32) (saw_sampler(sam, 0, frequency, k) * a * u);
+                saw_playback_temp[i * CHANNEL_COUNT + 1] +=
+                    (f32) (saw_sampler(sam, 1, frequency, k) * a * u);
+              }
 
               saw_voices[n].time++;
 
@@ -1517,8 +1592,6 @@ static void saw_ui_choose_instrument(saw_track_t *track, i64 x0,
     track->sampler.begin          = 0.;
     track->sampler.end            = 1.;
     track->sampler.tail           = .2;
-    track->sampler.fade_in        = 0.f;
-    track->sampler.fade_out       = 0.;
     track->sampler.crossfade      = .01;
     track->sampler.base_frequency = 440.;
     track->sampler.volume         = .5;
@@ -1667,7 +1740,12 @@ static void saw_ui_sampler(saw_sampler_t *sampler, i64 x0, i64 y0,
     nvgTextAlign(saw_nvg, NVG_ALIGN_CENTER | NVG_ALIGN_MIDDLE);
     nvgText(saw_nvg, x0 + width / 2,
             frame_height - y0 - height + sample_height / 2,
-            "Drop a WAV file here", NULL);
+#ifdef __EMSCRIPTEN__
+            "Not implemented for the web yet",
+#else
+            "Drop a WAV file here",
+#endif
+            NULL);
   }
 
   saw_ui_value_float(x, y0 + height - sample_height - text_height, w,
@@ -1680,18 +1758,12 @@ static void saw_ui_sampler(saw_sampler_t *sampler, i64 x0, i64 y0,
                      w, text_height, TINT_WHITE, SZ("Tail"), 100000,
                      0., 60., &sampler->tail);
   saw_ui_value_float(x, y0 + height - sample_height - text_height * 4,
-                     w, text_height, TINT_WHITE, SZ("Fade in"),
-                     100000, 0., 60., &sampler->fade_in);
-  saw_ui_value_float(x, y0 + height - sample_height - text_height * 5,
-                     w, text_height, TINT_WHITE, SZ("Fade out"),
-                     100000, 0., 60., &sampler->fade_out);
-  saw_ui_value_float(x, y0 + height - sample_height - text_height * 6,
                      w, text_height, TINT_WHITE, SZ("Crossfade"),
                      100000, 0., 60., &sampler->crossfade);
-  saw_ui_value_float(x, y0 + height - sample_height - text_height * 7,
+  saw_ui_value_float(x, y0 + height - sample_height - text_height * 5,
                      w, text_height, TINT_WHITE, SZ("Base freq."),
                      500, 1., 44100., &sampler->base_frequency);
-  saw_ui_value_float(x, y0 + height - sample_height - text_height * 8,
+  saw_ui_value_float(x, y0 + height - sample_height - text_height * 6,
                      w, text_height, TINT_WHITE, SZ("Volume."), 10000,
                      0., 2., &sampler->volume);
 
@@ -1701,23 +1773,22 @@ static void saw_ui_sampler(saw_sampler_t *sampler, i64 x0, i64 y0,
   nvgTextAlign(saw_nvg, NVG_ALIGN_LEFT | NVG_ALIGN_BASELINE);
   nvgText(saw_nvg, x,
           frame_height - y0 - height + sample_height +
-              (text_height * 19) / 2,
+              (text_height * 15) / 2,
           "Envelope", NULL);
 
-  saw_ui_value_float(x,
-                     y0 + height - sample_height - text_height * 11,
+  saw_ui_value_float(x, y0 + height - sample_height - text_height * 9,
                      w, text_height, TINT_WHITE, SZ("Sustain"), 10000,
                      0., 1., &sampler->envelope.sustain);
   saw_ui_value_float(x,
-                     y0 + height - sample_height - text_height * 12,
+                     y0 + height - sample_height - text_height * 10,
                      w, text_height, TINT_WHITE, SZ("Attack"), 100000,
                      0., 6., &sampler->envelope.attack);
   saw_ui_value_float(x,
-                     y0 + height - sample_height - text_height * 13,
+                     y0 + height - sample_height - text_height * 11,
                      w, text_height, TINT_WHITE, SZ("Decay"), 100000,
                      0., 6., &sampler->envelope.decay);
   saw_ui_value_float(x,
-                     y0 + height - sample_height - text_height * 14,
+                     y0 + height - sample_height - text_height * 12,
                      w, text_height, TINT_WHITE, SZ("Release"),
                      100000, 0., 6., &sampler->envelope.release);
 }
@@ -2555,14 +2626,12 @@ static void saw_init(void) {
               sam->outline.values[i] = fabs(v[k] + v[k + 1]) * .5;
             }
 
-          i64 begin, end, tail, fade_in, fade_out, crossfade, bfreq,
-              volume, sustain, attack, decay, release;
+          i64 begin, end, tail, crossfade, bfreq, volume, sustain,
+              attack, decay, release;
 
           SCAN_(" begin %lld", 1, &begin);
           SCAN_(" end %lld", 1, &end);
           SCAN_(" tail %lld", 1, &tail);
-          SCAN_(" fade_in %lld", 1, &fade_in);
-          SCAN_(" fade_out %lld", 1, &fade_out);
           SCAN_(" crossfade %lld", 1, &crossfade);
           SCAN_(" base_frequency %lld", 1, &bfreq);
           SCAN_(" volume %lld", 1, &volume);
@@ -2574,8 +2643,6 @@ static void saw_init(void) {
           sam->begin            = begin * .0001;
           sam->end              = end * .0001;
           sam->tail             = tail * .0001;
-          sam->fade_in          = fade_in * .0001;
-          sam->fade_out         = fade_out * .0001;
           sam->crossfade        = crossfade * .0001;
           sam->base_frequency   = bfreq * .0001;
           sam->volume           = volume * .0001;
@@ -2862,10 +2929,6 @@ static void saw_cleanup(void) {
                 (i64) floor(sam->end * 10000 + .5));
         fprintf(f, "tail            %lld\n",
                 (i64) floor(sam->tail * 10000 + .5));
-        fprintf(f, "fade_in         %lld\n",
-                (i64) floor(sam->fade_in * 10000 + .5));
-        fprintf(f, "fade_out        %lld\n",
-                (i64) floor(sam->fade_out * 10000 + .5));
         fprintf(f, "crossfade       %lld\n",
                 (i64) floor(sam->crossfade * 10000 + .5));
         fprintf(f, "base_frequency  %lld\n",