pianoroll: in progress

2 files changed, 168 insertions, 21 deletions

diff --git a/TODO b/TODO
index 7641fae..d5fd380 100644
--- a/TODO
+++ b/TODO
@@ -1,10 +1,13 @@
 To-Do list
 
-- Sheet editor UI
-- Playback control
+- UI: Piano roll
+- UI: Volume control
+- UI: Playback control
 - Simple tonal synth
+- Build: WebAssembly
 - Drum synth: kick, snare, cymbal
-- Track composing UI
+- UI: Track composing
+- Build: Faster recompilation
 
 
 Done
diff --git a/source/saw/main.c b/source/saw/main.c
index d32188f..b362ed7 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -31,30 +31,91 @@
 enum {
   SAW_CHANNEL_COUNT = 2,
   SAW_SAMPLE_RATE   = 44100,
+
+  VOICE_COUNT    = 4,
+  PIANOROLL_SIZE = 40
 };
 
 static struct NVGcontext *saw_nvg;
 static ma_device          saw_ma;
 
-static void saw_audio(ma_device *device, void *void_out_,
-                      void const *void_in_, ma_uint32 frame_count) {
-  static i64 t = 0;
+static i32 saw_mouse_x       = 0;
+static i32 saw_mouse_y       = 0;
+static i8  saw_lbutton_click = 0;
+static i8  saw_lbutton_down  = 0;
+static i8  saw_rbutton_click = 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 i32 saw_pianoroll_last_index                 = -1;
+static i8  saw_pianoroll_turned_off[PIANOROLL_SIZE] = { 0 };
 
-  f64 period    = M_PI * 2.;
-  f64 amplitude = .2;
-  f64 frequency = 240.;
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wunused-function"
+#  pragma GCC diagnostic ignored "-Wunknown-pragmas"
+#  pragma GCC            push_options
+#  pragma GCC            optimize("O3")
+#endif
+
+static f64 saw_envelope(f64 t, f64 attack, f64 decay, f64 sustain,
+                        f64 duration, f64 release) {
+  //  FIXME
+  //  Apply low-pass filter for the envelope curve to prevent
+  //  clicking.
+  //
 
+  if (t < attack)
+    return t / attack;
+  else if (t < attack + decay)
+    return 1. - (1. - sustain) * (t - attack) / decay;
+  else if (t < duration)
+    return sustain;
+  else if (t < duration + release)
+    return sustain * (duration + release - t) / release;
+  else
+    return 0.;
+}
+
+static void saw_audio(ma_device *device, void *void_out_,
+                      void const *void_in_, ma_uint32 frame_count) {
   f32 *out = (f32 *) void_out_;
 
   for (i64 i = 0; i < frame_count; i++) {
-    f64 k          = (period * frequency) / SAW_SAMPLE_RATE;
-    out[i * 2]     = (f32) (sin(k * t) * amplitude);
-    out[i * 2 + 1] = (f32) (sin(k * t) * amplitude);
+    out[i * 2]     = 0.f;
+    out[i * 2 + 1] = 0.f;
+  }
+
+  for (i32 n = 0; n < VOICE_COUNT; n++) {
+    if (!saw_voice_on[n])
+      continue;
+
+    f64 period    = M_PI * 2.;
+    f64 frequency = pow(2., 6.5 + saw_voice_pitch[n] / 12.);
+
+    for (i64 i = 0; i < frame_count; i++) {
+      f64 t         = (f64) saw_voice_time[n] / (f64) SAW_SAMPLE_RATE;
+      f64 amplitude = .4 * saw_envelope(t, .007, .2, .2, .6, .4);
+      f64 k         = period * frequency;
 
-    t++;
+      out[i * 2] += (f32) (sin(k * t) * amplitude);
+      out[i * 2 + 1] += (f32) (sin(k * t) * amplitude);
+
+      saw_voice_time[n]++;
+
+      if (t > 1.0)
+        saw_voice_on[n] = 0;
+    }
   }
 }
 
+#ifdef __GNUC__
+#  pragma GCC            pop_options
+#  pragma GCC diagnostic pop
+#endif
+
 static void saw_init(void) {
 #ifdef SOKOL_GLCORE33
   saw_nvg = nvgCreateGL3(NVG_ANTIALIAS | NVG_STENCIL_STROKES);
@@ -80,23 +141,78 @@ static void saw_init(void) {
 }
 
 static void saw_frame(void) {
-  int width  = sapp_width();
-  int height = sapp_height();
+  i32 width  = sapp_width();
+  i32 height = sapp_height();
 
   glViewport(0, 0, width, height);
-  glClearColor(.3f, .2f, .4f, 1.f);
+  glClearColor(.23f, .19f, .16f, 1.f);
   glClearDepthf(1.f);
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT |
           GL_STENCIL_BUFFER_BIT);
 
   nvgBeginFrame(saw_nvg, width, height, sapp_dpi_scale());
 
-  nvgBeginPath(saw_nvg);
-  nvgRect(saw_nvg, 100, 100, 300, 200);
-  nvgFillColor(saw_nvg, nvgRGBA(255, 192, 0, 255));
-  nvgFill(saw_nvg);
+  //  Draw piano roll
+  //
+
+  i32 x0 = 20;
+  i32 y0 = 20;
+
+  i32 pianokey_height = 40;
+  i32 pianokey_width  = 100;
+  i32 pianokey_border = 2;
+
+  for (i32 i = 0; i < PIANOROLL_SIZE; i++) {
+    i32 x = x0 + pianokey_border;
+    i32 y = height - y0 - (i + 1) * pianokey_height;
+    i32 w = pianokey_width - pianokey_border * 2;
+    i32 h = pianokey_height - pianokey_border * 2;
+
+    if (y > height - pianokey_height)
+      continue;
+    if (y < 0)
+      break;
+
+    nvgBeginPath(saw_nvg);
+    nvgRect(saw_nvg, x, y, w, h);
+
+    i8 has_cursor = saw_mouse_x >= x && saw_mouse_x < x + w &&
+                    saw_mouse_y >= y && saw_mouse_y < y + h;
+
+    nvgFillColor(saw_nvg, saw_pianoroll_turned_off[i]
+                              ? nvgRGBA(220, 220, 220, 160)
+                          : has_cursor ? nvgRGBA(200, 200, 255, 255)
+                                       : nvgRGBA(220, 220, 220, 255));
+    nvgFill(saw_nvg);
+
+    if (has_cursor) {
+      if (!saw_pianoroll_turned_off[i] &&
+          (saw_lbutton_click ||
+           (saw_lbutton_down && saw_pianoroll_last_index != i))) {
+        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_on[0]          = 1;
+        saw_voice_pitch[0]       = i;
+        saw_voice_time[0]        = 0;
+        saw_pianoroll_last_index = i;
+      }
+
+      if (saw_rbutton_click)
+        saw_pianoroll_turned_off[i] = !saw_pianoroll_turned_off[i];
+    }
+  }
 
   nvgEndFrame(saw_nvg);
+
+  //  Cleanup input state.
+  //
+
+  saw_lbutton_click = 0;
+  saw_rbutton_click = 0;
 }
 
 static void saw_cleanup(void) {
@@ -109,7 +225,35 @@ static void saw_cleanup(void) {
 #endif
 }
 
-static void saw_event(sapp_event const *event) { }
+static void saw_event(sapp_event const *event) {
+  switch (event->type) {
+    case SAPP_EVENTTYPE_MOUSE_MOVE:
+      saw_mouse_x = event->mouse_x;
+      saw_mouse_y = event->mouse_y;
+      break;
+
+    case SAPP_EVENTTYPE_MOUSE_DOWN:
+
+      switch (event->mouse_button) {
+        case SAPP_MOUSEBUTTON_LEFT:
+          saw_lbutton_down  = 1;
+          saw_lbutton_click = 1;
+          break;
+        case SAPP_MOUSEBUTTON_RIGHT: saw_rbutton_click = 1; break;
+        default:;
+      }
+      break;
+
+    case SAPP_EVENTTYPE_MOUSE_UP:
+      switch (event->mouse_button) {
+        case SAPP_MOUSEBUTTON_LEFT: saw_lbutton_down = 0; break;
+        default:;
+      }
+      break;
+
+    default:;
+  }
+}
 
 char const *__lsan_default_suppressions() {
   //  There is leaks in NVidia driver on Linux.