piano roll and playback control

2 files changed, 114 insertions, 28 deletions

diff --git a/TODO b/TODO
index 795ab11..2e354db 100644
--- a/TODO
+++ b/TODO
@@ -1,8 +1,6 @@
 To-Do list
 
-- UI: Piano roll
 - UI: Volume control
-- UI: Playback control
 - Sound: Buffering.
 - Sound: Simple tonal synth
 - Build: WebAssembly
@@ -19,3 +17,5 @@ Done
 - Script for fetching dependencies.
 - nanovg and miniaudio setup.
 - Build: Faster recompilation
+- UI: Piano roll
+- UI: Playback control
diff --git a/source/saw/main.c b/source/saw/main.c
index e65b5b9..d974e4b 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -63,7 +63,9 @@ static f64 saw_voice_duration[VOICE_COUNT] = { 0 };
 
 static i32         saw_roll_last_index            = -1;
 static i8          saw_roll_turned_off[ROLL_SIZE] = { 0 };
-static saw_sheet_t saw_roll_sheet = { .rate = 4, .notes = { 0 } };
+static saw_sheet_t saw_roll_sheet   = { .rate = 6, .notes = { 0 } };
+static i8          saw_roll_playing = 0;
+static i64         saw_roll_frame   = 0;
 
 static i8  saw_grid_input = 0;
 static i32 saw_grid_note  = 0;
@@ -97,8 +99,41 @@ static f64 saw_envelope(f64 t, f64 attack, f64 decay, f64 sustain,
     return 0.;
 }
 
+static void saw_roll_playback(i32 frame_count) {
+  if (!saw_roll_playing)
+    return;
+
+  for (i32 i = 0; i < SHEET_SIZE; i++) {
+    saw_sheet_note_t *p = saw_roll_sheet.notes + i;
+    if (!p->enabled)
+      continue;
+    i64 frame = (p->time * SAW_SAMPLE_RATE) / saw_roll_sheet.rate;
+    if (saw_roll_frame + frame_count <= frame ||
+        saw_roll_frame > frame)
+      continue;
+    if (saw_voice_on[VOICE_COUNT - 1])
+      continue;
+
+    for (i32 n = VOICE_COUNT - 1; n > 0; --n) {
+      saw_voice_on[n]       = saw_voice_on[n - 1];
+      saw_voice_pitch[n]    = saw_voice_pitch[n - 1];
+      saw_voice_time[n]     = saw_voice_time[n - 1];
+      saw_voice_duration[n] = saw_voice_duration[n - 1];
+    }
+
+    saw_voice_on[0]       = 1;
+    saw_voice_pitch[0]    = p->pitch;
+    saw_voice_time[0]     = 0;
+    saw_voice_duration[0] = ((f64) p->duration) / saw_roll_sheet.rate;
+  }
+
+  saw_roll_frame += frame_count;
+}
+
 static void saw_audio(ma_device *device, void *void_out_,
                       void const *void_in_, ma_uint32 frame_count) {
+  saw_roll_playback(frame_count);
+
   f32 *out = (f32 *) void_out_;
 
   for (i64 i = 0; i < frame_count; i++) {
@@ -111,13 +146,13 @@ static void saw_audio(ma_device *device, void *void_out_,
       continue;
 
     f64 period    = M_PI * 2.;
-    f64 frequency = pow(2., 7.3 + saw_voice_pitch[n] / 12.);
+    f64 frequency = pow(2., 7.6 + saw_voice_pitch[n] / 12.);
     f64 amplitude = .2;
 
     //  envelope
     f64 attack   = .007;
-    f64 decay    = .2;
-    f64 sustain  = .2;
+    f64 decay    = .3;
+    f64 sustain  = .15;
     f64 duration = saw_voice_duration[n];
     f64 release  = .4;
 
@@ -187,7 +222,7 @@ static void saw_frame(void) {
   i32 x0 = 20;
   i32 y0 = 20;
 
-  i32 pianokey_height = 40;
+  i32 pianokey_height = 35;
   i32 pianokey_width  = 100;
   i32 roll_border     = 2;
 
@@ -298,10 +333,10 @@ static void saw_frame(void) {
                      saw_mouse_y >= y && saw_mouse_y < y + h;
 
         nvgFillColor(saw_nvg, saw_roll_turned_off[pitch]
-                                  ? nvgRGBA(180, 180, 180, 120)
+                                  ? nvgRGBA(160, 150, 120, 100)
                               : has_cursor
                                   ? nvgRGBA(180, 180, 220, 160)
-                                  : nvgRGBA(180, 180, 180, 160));
+                                  : nvgRGBA(170, 160, 140, 150));
         nvgFill(saw_nvg);
 
         //  Empty cell input
@@ -348,30 +383,69 @@ static void saw_frame(void) {
         }
       }
     }
+  }
 
-    //  Note stretching
-    //
+  //  Note stretching input
+  //
 
-    if (saw_grid_input) {
-      if (saw_lbutton_down) {
-        i32 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset) /
-                sheet_scale;
-
-        if (t >= 0) {
-          saw_sheet_note_t *p = saw_roll_sheet.notes + saw_grid_note;
-          if (saw_grid_time <= t) {
-            p->time     = saw_grid_time;
-            p->duration = 1 + t - saw_grid_time;
-          } else {
-            p->time     = t;
-            p->duration = saw_grid_time - t;
-          }
+  if (saw_grid_input) {
+    if (saw_lbutton_down) {
+      i32 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset) /
+              sheet_scale;
+
+      if (t >= 0) {
+        saw_sheet_note_t *p = saw_roll_sheet.notes + saw_grid_note;
+        if (saw_grid_time <= t) {
+          p->time     = saw_grid_time;
+          p->duration = 1 + t - saw_grid_time;
+        } else {
+          p->time     = t;
+          p->duration = saw_grid_time - t;
         }
-      } else
-        saw_grid_input = 0;
-    }
+      }
+
+      saw_sheet_note_t *p = saw_roll_sheet.notes + saw_grid_note;
+      for (i32 n = 0; n < SHEET_SIZE; n++) {
+        if (n == saw_grid_note)
+          continue;
+        saw_sheet_note_t *q = saw_roll_sheet.notes + n;
+        if (!q->enabled || q->pitch != p->pitch)
+          continue;
+        if (q->time < saw_grid_time &&
+            q->time + q->duration > p->time) {
+          p->time     = q->time + q->duration;
+          p->duration = saw_grid_time > p->time
+                            ? saw_grid_time - p->time
+                            : 1;
+        }
+        if (q->time > saw_grid_time &&
+            q->time < p->time + p->duration) {
+          p->time     = saw_grid_time;
+          p->duration = q->time - saw_grid_time;
+          assert(p->duration > 0);
+        }
+      }
+    } else
+      saw_grid_input = 0;
   }
 
+  //  Playback indicator
+  //
+
+  f64 playback_time = ((f64) saw_roll_frame) / SAW_SAMPLE_RATE;
+
+  i32 x = x0 + pianokey_width + sheet_offset - roll_border * 2 +
+          (i32) (playback_time * saw_roll_sheet.rate * sheet_scale +
+                 .5);
+  i32 y = 0;
+  i32 w = roll_border * 4;
+  i32 h = height - y0;
+
+  nvgBeginPath(saw_nvg);
+  nvgRect(saw_nvg, x, y, w, h);
+  nvgFillColor(saw_nvg, nvgRGBA(240, 240, 80, 220));
+  nvgFill(saw_nvg);
+
   nvgEndFrame(saw_nvg);
 
   //  Cleanup input state.
@@ -420,6 +494,18 @@ static void saw_event(sapp_event const *event) {
       }
       break;
 
+    case SAPP_EVENTTYPE_KEY_DOWN:
+      if (!event->key_repeat) {
+        switch (event->key_code) {
+          case SAPP_KEYCODE_SPACE:
+            saw_roll_playing = !saw_roll_playing;
+            break;
+          case SAPP_KEYCODE_ENTER: saw_roll_frame = 0; break;
+          default:;
+        }
+      }
+      break;
+
     default:;
   }
 }