Piano roll panning

2 files changed, 128 insertions, 60 deletions

diff --git a/TODO b/TODO
index 6ae9e3c..c23e262 100644
--- a/TODO
+++ b/TODO
@@ -22,6 +22,7 @@ To-Do list
 - UI: Panning and scaling
 - Sound: Track looping
 - Implement Undo and Redo
+- Hot loading
 
 Done
 
@@ -31,3 +32,4 @@ Done
 - UI: Piano roll
 - UI: Playback control
 - UI: Text rendering
+- UI: Piano roll panning
diff --git a/source/saw/main.c b/source/saw/main.c
index 3f34e51..9b4fbde 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -36,6 +36,13 @@ enum {
 typedef struct {
   i8  enabled;
   i64 time;
+  f64 duration;
+  f64 frequency;
+} saw_voice_t;
+
+typedef struct {
+  i8  enabled;
+  i64 time;
   i64 duration;
   i64 pitch;
 } saw_sheet_note_t;
@@ -53,6 +60,9 @@ typedef struct {
   i32         grid_note;
   i32         grid_pitch;
   i32         grid_time;
+  i8          offset_input;
+  i64         offset_x;
+  i64         offset_y;
 } saw_roll_t;
 
 static struct NVGcontext *saw_nvg;
@@ -66,16 +76,15 @@ static i8  saw_lbutton_click = 0;
 static i8  saw_lbutton_down  = 0;
 static i8  saw_rbutton_click = 0;
 static i8  saw_rbutton_down  = 0;
-
-static i8  saw_voice_on[VOICE_COUNT]       = { 0 };
-static i32 saw_voice_pitch[VOICE_COUNT]    = { 0 };
-static i64 saw_voice_time[VOICE_COUNT]     = { 0 };
-static f64 saw_voice_duration[VOICE_COUNT] = { 0 };
+static i8  saw_mbutton_click = 0;
+static i8  saw_mbutton_down  = 0;
 
 static i8  saw_playback_on    = 0;
 static i64 saw_playback_frame = 0;
+static i64 saw_current_roll   = 0;
 
-static saw_roll_t saw_rolls[ROLL_COUNT];
+static saw_voice_t saw_voices[VOICE_COUNT] = { 0 };
+static saw_roll_t  saw_rolls[ROLL_COUNT];
 
 #ifdef __GNUC__
 #  pragma GCC diagnostic push
@@ -119,20 +128,18 @@ static void saw_playback(i32 frame_count) {
       if (saw_playback_frame + frame_count <= frame ||
           saw_playback_frame > frame)
         continue;
-      if (saw_voice_on[VOICE_COUNT - 1])
+      if (saw_voices[VOICE_COUNT - 1].enabled)
         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];
-      }
+      for (i32 n = VOICE_COUNT - 1; n > 0; --n)
+        saw_voices[n] = saw_voices[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) / roll->sheet.rate;
+      saw_voices[0] = (saw_voice_t) {
+        .enabled   = 1,
+        .time      = 0,
+        .duration  = ((f64) p->duration) / roll->sheet.rate,
+        .frequency = pow(2., 7.6 + p->pitch / 12.)
+      };
     }
   }
 
@@ -151,22 +158,22 @@ static void saw_audio(ma_device *device, void *void_out_,
   }
 
   for (i32 n = 0; n < VOICE_COUNT; n++) {
-    if (!saw_voice_on[n])
+    if (!saw_voices[n].enabled)
       continue;
 
     f64 period    = M_PI * 2.;
-    f64 frequency = pow(2., 7.6 + saw_voice_pitch[n] / 12.);
+    f64 frequency = saw_voices[n].frequency;
     f64 amplitude = .2;
 
     //  envelope
     f64 attack   = .007;
     f64 decay    = .3;
     f64 sustain  = .15;
-    f64 duration = saw_voice_duration[n];
+    f64 duration = saw_voices[n].duration;
     f64 release  = .4;
 
     for (i64 i = 0; i < frame_count; i++) {
-      f64 t = (f64) saw_voice_time[n] / (f64) SAW_SAMPLE_RATE;
+      f64 t = (f64) saw_voices[n].time / (f64) SAW_SAMPLE_RATE;
       f64 a = amplitude * saw_envelope(t, attack, decay, sustain,
                                        duration, release);
       f64 k = period * frequency;
@@ -174,10 +181,10 @@ static void saw_audio(ma_device *device, void *void_out_,
       out[i * 2] += (f32) (sin(k * t) * a);
       out[i * 2 + 1] += (f32) (sin(k * t) * a);
 
-      saw_voice_time[n]++;
+      saw_voices[n].time++;
 
       if (t > duration + release)
-        saw_voice_on[n] = 0;
+        saw_voices[n].enabled = 0;
     }
   }
 }
@@ -225,7 +232,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   for (i32 pitch = 0; pitch < ROLL_SIZE; pitch++) {
     i32 x = x0 + roll_border;
     i32 y = frame_height - y0 - (pitch + 1) * pianokey_height +
-            roll_border;
+            roll_border + roll->offset_y;
     i32 w = pianokey_width - roll_border * 2;
     i32 h = pianokey_height - roll_border * 2;
 
@@ -255,18 +262,15 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       if (!roll->turned_off[pitch] &&
           (saw_lbutton_click ||
            (saw_lbutton_down && roll->last_index != pitch)) &&
-          !saw_voice_on[VOICE_COUNT - 1]) {
-        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]    = pitch;
-        saw_voice_time[0]     = 0;
-        saw_voice_duration[0] = .6;
+          !saw_voices[VOICE_COUNT - 1].enabled) {
+        for (i32 n = VOICE_COUNT - 1; n > 0; --n)
+          saw_voices[n] = saw_voices[n - 1];
+
+        saw_voices[0] = (saw_voice_t) { .enabled   = 1,
+                                        .time      = 0,
+                                        .duration  = .6,
+                                        .frequency = pow(
+                                            2., 7.6 + pitch / 12.) };
       }
 
       if (saw_rbutton_click)
@@ -279,11 +283,19 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   if (!hover_any)
     roll->last_index = -1;
 
+  if (saw_mbutton_click && saw_mouse_x >= x0 &&
+      saw_mouse_y >= frame_height - y0 - height &&
+      saw_mouse_x < x0 + width && saw_mouse_y < frame_height - y0)
+    roll->offset_input = 1;
+  if (!saw_mbutton_down && roll->offset_input)
+    roll->offset_input = 0;
+
   //  Draw music sheet
   //
 
   for (i32 pitch = 0; pitch < ROLL_SIZE; pitch++) {
-    i32 y = frame_height - y0 - (pitch + 1) * pianokey_height;
+    i32 y = frame_height - y0 - (pitch + 1) * pianokey_height +
+            roll->offset_y;
 
     if (y > frame_height - y0)
       continue;
@@ -293,9 +305,10 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
     i32 h = pianokey_height;
 
     for (i32 t = 0;; t++) {
-      i32 x = x0 + pianokey_width + sheet_offset + t * sheet_scale;
+      i32 x = x0 + pianokey_width + sheet_offset + t * sheet_scale +
+              roll->offset_x;
 
-      if (x >= x0 + width - roll_border)
+      if (x >= x0 + width - sheet_scale - roll_border)
         break;
 
       i32 note = -1;
@@ -315,6 +328,9 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
         //  Draw empty cell
         //
 
+        if (x < x0 + pianokey_width + sheet_offset)
+          continue;
+
         i32 w = sheet_scale;
 
         nvgBeginPath(saw_nvg);
@@ -354,16 +370,43 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
         has_cursor = saw_mouse_x >= x && saw_mouse_x < x + w &&
                      saw_mouse_y >= y && saw_mouse_y < y + h;
 
+        if (x + w - sheet_scale < x0 + pianokey_width + sheet_offset)
+          continue;
+
         if (t == roll->sheet.notes[note].time) {
           //  Draw note
           //
 
+          i64 t0 = (t * SAW_SAMPLE_RATE) / roll->sheet.rate;
+          i64 t1 = ((t + roll->sheet.notes[note].duration) *
+                    SAW_SAMPLE_RATE) /
+                   roll->sheet.rate;
+
+          i8 is_playing = saw_playback_on &&
+                          saw_playback_frame >= t0 &&
+                          saw_playback_frame < t1;
+
+          i32 underflow = (x0 + pianokey_width + sheet_offset +
+                           sheet_scale - 1 - x) /
+                          sheet_scale;
+          i32 overflow = (x + w + sheet_scale + 1 - x0 - width) /
+                         sheet_scale;
+
+          if (underflow > 0) {
+            x += underflow * sheet_scale;
+            w -= underflow * sheet_scale;
+          }
+
+          if (overflow > 0)
+            w -= overflow * sheet_scale;
+
           nvgBeginPath(saw_nvg);
           nvgRect(saw_nvg, x + roll_border, y + roll_border,
                   w - roll_border * 2, h - roll_border * 2);
 
-          nvgFillColor(saw_nvg, has_cursor
-                                    ? nvgRGBA(180, 180, 220, 255)
+          nvgFillColor(saw_nvg,
+                       is_playing   ? nvgRGBA(255, 230, 200, 255)
+                       : has_cursor ? nvgRGBA(180, 180, 220, 255)
                                     : nvgRGBA(180, 180, 180, 255));
           nvgFill(saw_nvg);
 
@@ -382,7 +425,8 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
   if (roll->grid_input) {
     if (saw_lbutton_down) {
-      i32 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset) /
+      i32 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset -
+               roll->offset_x) /
               sheet_scale;
 
       if (t >= 0) {
@@ -426,15 +470,19 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
   f64 playback_time = ((f64) saw_playback_frame) / SAW_SAMPLE_RATE;
 
-  i32 x = x0 + pianokey_width + sheet_offset - roll_border * 2 +
+  i32 x = x0 + pianokey_width + sheet_offset + roll->offset_x -
+          roll_border * 2 +
           (i32) (playback_time * roll->sheet.rate * sheet_scale + .5);
   i32 w = roll_border * 4;
 
-  nvgBeginPath(saw_nvg);
-  nvgRect(saw_nvg, x, frame_height - y0 - height + text_height, w,
-          height - text_height);
-  nvgFillColor(saw_nvg, nvgRGBA(240, 240, 80, 180));
-  nvgFill(saw_nvg);
+  if (x >= x0 + pianokey_width + sheet_offset - roll_border * 2 &&
+      x < x0 + width) {
+    nvgBeginPath(saw_nvg);
+    nvgRect(saw_nvg, x, frame_height - y0 - height + text_height, w,
+            height - text_height);
+    nvgFillColor(saw_nvg, nvgRGBA(240, 240, 80, 180));
+    nvgFill(saw_nvg);
+  }
 }
 
 static void saw_init(void) {
@@ -469,14 +517,18 @@ static void saw_init(void) {
     printf("nvgCreateFontMem failed.\n");
 
   for (i32 i = 0; i < ROLL_COUNT; i++)
-    saw_rolls[i] = (saw_roll_t) { .last_index = -1,
-                                  .turned_off = { 0 },
-                                  .sheet      = { .rate  = 6,
-                                                  .notes = { 0 } },
-                                  .grid_input = 0,
-                                  .grid_note  = 0,
-                                  .grid_pitch = 0,
-                                  .grid_time  = 0 };
+    saw_rolls[i] = (saw_roll_t) {
+      .last_index   = -1,
+      .turned_off   = { 0 },
+      .sheet        = { .rate = 6, .notes = { 0 } },
+      .grid_input   = 0,
+      .grid_note    = 0,
+      .grid_pitch   = 0,
+      .grid_time    = 0,
+      .offset_input = 0,
+      .offset_x     = 0,
+      .offset_y     = 0,
+    };
 }
 
 static void saw_frame(void) {
@@ -491,10 +543,11 @@ static void saw_frame(void) {
 
   nvgBeginFrame(saw_nvg, frame_width, frame_height, sapp_dpi_scale());
 
-  saw_ui_roll(saw_rolls, 0, 10, frame_width, frame_height / 2 - 20,
-              SZ("Track 1"));
-  saw_ui_roll(saw_rolls + 1, 0, frame_height / 2 + 10, frame_width,
-              frame_height / 2 - 20, SZ("Track 2"));
+  char buf[64];
+  sprintf(buf, "Track %lld", saw_current_roll + 1);
+
+  saw_ui_roll(saw_rolls + saw_current_roll, 0, 10, frame_width,
+              frame_height / 2 - 20, kit_str(strlen(buf), buf));
 
   nvgEndFrame(saw_nvg);
 
@@ -503,6 +556,7 @@ static void saw_frame(void) {
 
   saw_lbutton_click = 0;
   saw_rbutton_click = 0;
+  saw_mbutton_click = 0;
 }
 
 static void saw_cleanup(void) {
@@ -520,6 +574,13 @@ static void saw_event(sapp_event const *event) {
     case SAPP_EVENTTYPE_MOUSE_MOVE:
       saw_mouse_x = event->mouse_x;
       saw_mouse_y = event->mouse_y;
+
+      for (i64 i = 0; i < ROLL_COUNT; i++)
+        if (saw_rolls[i].offset_input) {
+          saw_rolls[i].offset_x += event->mouse_dx;
+          saw_rolls[i].offset_y += event->mouse_dy;
+        }
+
       break;
 
     case SAPP_EVENTTYPE_MOUSE_DOWN:
@@ -532,6 +593,10 @@ static void saw_event(sapp_event const *event) {
           saw_rbutton_down  = 1;
           saw_rbutton_click = 1;
           break;
+        case SAPP_MOUSEBUTTON_MIDDLE:
+          saw_mbutton_down  = 1;
+          saw_mbutton_click = 1;
+          break;
         default:;
       }
       break;
@@ -540,6 +605,7 @@ static void saw_event(sapp_event const *event) {
       switch (event->mouse_button) {
         case SAPP_MOUSEBUTTON_LEFT: saw_lbutton_down = 0; break;
         case SAPP_MOUSEBUTTON_RIGHT: saw_rbutton_down = 0; break;
+        case SAPP_MOUSEBUTTON_MIDDLE: saw_mbutton_down = 0; break;
         default:;
       }
       break;