1 files changed, 218 insertions, 0 deletions

diff --git a/src/sequencer.c b/src/sequencer.c
new file mode 100644
index 0000000..4231def
--- /dev/null
+++ b/src/sequencer.c
@@ -0,0 +1,218 @@
+#define SPRITE_NOTE_NAMES_W 16
+#define SPRITE_NOTE_NAMES_H 8
+
+u32 sprite_note_names[] = {
+    0x77417111, 0x77000000, 0x00000000, 0x00000000,
+    0x13157555, 0x33000000, 0x07040701, 0x07000000,
+    0x73457515, 0x73000000, 0x00000000, 0x00000000,
+    0x17117351, 0x37000000, 0x07040701, 0x07000000,
+    0x77417311, 0x77000000, 0x00000000, 0x00000000,
+    0x77417311, 0x71000000, 0x00000000, 0x00000000,
+    0x17117155, 0x37000000, 0x07040701, 0x07000000,
+    0x77417115, 0x77000000, 0x00000000, 0x00000000,
+    0x17157557, 0x35000000, 0x07040701, 0x07000000,
+    0x77457517, 0x75000000, 0x00000000, 0x00000000,
+    0x17157355, 0x37000000, 0x07040701, 0x07000000,
+    0x77457315, 0x77000000, 0x00000000, 0x00000000,
+    0x77416141, 0x77000000, 0x00000000, 0x00000000,
+    0x13157555, 0x33000000, 0x07040604, 0x07000000,
+    0x73456545, 0x73000000, 0x00000000, 0x00000000,
+    0x17117351, 0x37000000, 0x07040604, 0x07000000,
+    0x77416341, 0x77000000, 0x00000000, 0x00000000,
+    0x77416341, 0x71000000, 0x00000000, 0x00000000,
+    0x17117155, 0x37000000, 0x07040604, 0x07000000,
+    0x77416145, 0x77000000, 0x00000000, 0x00000000,
+    0x17157557, 0x35000000, 0x07040604, 0x07000000,
+    0x77456547, 0x75000000, 0x00000000, 0x00000000,
+    0x17157355, 0x37000000, 0x07040604, 0x07000000,
+    0x77456345, 0x77000000, 0x00000000, 0x00000000,
+    0x47615171, 0x47000000, 0x00000000, 0x00000000,
+    0x13157555, 0x33000000, 0x04060507, 0x04000000,
+    0x43655575, 0x43000000, 0x00000000, 0x00000000,
+    0x17117351, 0x37000000, 0x04060507, 0x04000000,
+    0x47615371, 0x47000000, 0x00000000, 0x00000000,
+    0x47615371, 0x41000000, 0x00000000, 0x00000000,
+    0x17117155, 0x37000000, 0x04060507, 0x04000000,
+    0x47615175, 0x47000000, 0x00000000, 0x00000000,
+    0x17157557, 0x35000000, 0x04060507, 0x04000000,
+    0x47655577, 0x45000000, 0x00000000, 0x00000000,
+    0x17157355, 0x37000000, 0x04060507, 0x04000000,
+    0x47655375, 0x47000000, 0x00000000, 0x00000000,
+    0x77117141, 0x77000000, 0x00000000, 0x00000000,
+    0x13157555, 0x33000000, 0x07010704, 0x07000000,
+    0x73157545, 0x73000000, 0x00000000, 0x00000000,
+    0x17117351, 0x37000000, 0x07010704, 0x07000000,
+    0x77117341, 0x77000000, 0x00000000, 0x00000000,
+    0x77117341, 0x71000000, 0x00000000, 0x00000000,
+    0x17117155, 0x37000000, 0x07010704, 0x07000000,
+    0x77117145, 0x77000000, 0x00000000, 0x00000000,
+    0x17157557, 0x35000000, 0x07010704, 0x07000000,
+    0x77157547, 0x75000000, 0x00000000, 0x00000000,
+    0x17157355, 0x37000000, 0x07010704, 0x07000000,
+    0x77157345, 0x77000000, 0x00000000, 0x00000000,
+    0x77117151, 0x77000000, 0x00000000, 0x00000000,
+    0x13157555, 0x33000000, 0x07010705, 0x07000000,
+    0x73157555, 0x73000000, 0x00000000, 0x00000000,
+    0x17117351, 0x37000000, 0x07010705, 0x07000000,
+    0x77117351, 0x77000000, 0x00000000, 0x00000000,
+    0x77117351, 0x71000000, 0x00000000, 0x00000000,
+    0x17117155, 0x37000000, 0x07010705, 0x07000000,
+    0x77117155, 0x77000000, 0x00000000, 0x00000000,
+    0x17157557, 0x35000000, 0x07010705, 0x07000000,
+    0x77157557, 0x75000000, 0x00000000, 0x00000000,
+    0x17157355, 0x37000000, 0x07010705, 0x07000000,
+    0x77157355, 0x77000000, 0x00000000, 0x00000000,
+    0x77412111, 0x17000000, 0x00000000, 0x00000000,
+    0x13157555, 0x33000000, 0x07040201, 0x01000000,
+    0x73452515, 0x13000000, 0x00000000, 0x00000000,
+    0x17117351, 0x37000000, 0x07040201, 0x01000000,
+    0x77412311, 0x17000000, 0x00000000, 0x00000000,
+    0x77412311, 0x11000000, 0x00000000, 0x00000000,
+    0x17117155, 0x37000000, 0x07040201, 0x01000000,
+    0x77412115, 0x17000000, 0x00000000, 0x00000000,
+    0x17157557, 0x35000000, 0x07040201, 0x01000000,
+    0x77452517, 0x15000000, 0x00000000, 0x00000000,
+    0x17157355, 0x37000000, 0x07040201, 0x01000000,
+    0x77452315, 0x17000000, 0x00000000, 0x00000000,
+    0x77517151, 0x77000000, 0x00000000, 0x00000000,
+};
+
+typedef struct SeqTrigger {
+    bool trigger;
+    Note note;
+    // TODO: ...
+} SeqTrigger;
+
+static SeqTrigger sequence_synth[] = {
+    {true, NOTE_D_4},
+    {true, NOTE_F_4},
+    {true, NOTE_A_4},
+    {true, NOTE_C_5},
+
+    {true, NOTE_D_4},
+    {false, NOTE_D_4},
+    {false, NOTE_D_4},
+    {false, NOTE_D_4},
+
+    {true, NOTE_D_4},
+    {true, NOTE_F_4},
+    {true, NOTE_A_4},
+    {true, NOTE_C_5},
+
+    {true, NOTE_D_4},
+    {false, NOTE_D_4},
+    {true, NOTE_A_4},
+    {false, NOTE_A_5},
+};
+
+static int step_counter = 0;
+static Note active_note;
+
+void
+irq_timer_0(void) {
+    active_note = sequence_synth[step_counter].note;
+    if (sequence_synth[step_counter].trigger) {
+        SOUND_SQUARE1_CTRL = SOUND_SQUARE_ENV_VOL(13) | SOUND_SQUARE_ENV_TIME(4) | SOUND_SQUARE_DUTY(2);
+        SOUND_SQUARE1_FREQ = SOUND_SQUARE_RESET | sound_rates[active_note];
+    }
+    step_counter = (step_counter + 1) % 16;
+}
+
+void
+set_time(int bpm) {
+    // The number of ticks of a 1024 cycle clock in a step based on the BPM can
+    // be calculated as:
+    //     X bpm -> 60000 / 4 / bpm = Y ms = Ye-3 s
+    //     Y ms  -> Ye-3 / 59.99e-9 /1024 = Z ticks
+    // We have to operate on integer values, so the numbers have been
+    // precalculated to `n_ticks = 244181 / bmp`
+    int n_ticks = -244181 / bpm;
+
+    irs_set(IRQ_TIMER_0, irq_timer_0);
+    TIMER_DATA_0 = n_ticks;
+    TIMER_CTRL_0 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
+}
+
+static size_t note_sprites_id = 0;
+
+//
+// Sequencer sprite memory.
+//
+// Currently we load all sequencer sprite memory in the VRAM:
+//
+// - Note names: 0-73x2 tiles
+// - ...
+//
+// The order of OBJs correspond to:
+//
+// - 000-015 step note names.
+// - 015-029 step trigger steps.
+// - 030-045 step duration indicators.
+// - 046-046 current step marker.
+// - 047-047 trigger selection indicator.
+//
+
+size_t obj_counter = 0;
+
+typedef struct SeqSprite {
+    u8 id;
+    int x;
+    int y;
+    u16 obj_attr_0;
+    u16 obj_attr_1;
+    u16 obj_attr_2;
+} SeqSprite;
+
+#define SEQ_POS_X 20
+#define SEQ_POS_Y 20
+
+// SeqSprite seq_sprites[] = {
+//     // 000-015: Step note names.
+//     {
+//         .x = SEQ_POS_X,
+//         .y = SEQ_POS_Y,
+//         .obj_attr_0 = OBJ_SHAPE_WIDE,
+//         .obj_attr_1 = OBJ_SHAPE_SMALL,
+//         .obj_attr_2 = 0,
+//     },
+// };
+
+SeqSprite seq_sprites[16] = {0};
+
+void
+init_sequencer_sprites() {
+    // Load note sprites.
+    note_sprites_id = load_packed_sprite_data(&sprite_note_names, 2, 73);
+
+    for (size_t i = 0; i < 16; ++i) {
+        int x = SEQ_POS_X + i * 16;
+        int y = SEQ_POS_Y;
+        if (i >= 8) {
+            y += 32;
+            x -= 8 * 16;
+        }
+        seq_sprites[i].x = x;
+        seq_sprites[i].y = y;
+
+        seq_sprites[i].id = obj_counter++;
+        seq_sprites[i].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        // TODO: They should start hidden until the update function changes that.
+        // seq_sprites[i].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_HIDDEN;
+        seq_sprites[i].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
+    }
+}
+
+void
+render_sequencer_sprites() {
+    size_t len = sizeof(seq_sprites) / sizeof(SeqSprite);
+    for (size_t i = 0; i < len; ++i) {
+        size_t id = seq_sprites[i].id;
+        // TODO: This needs to be done in an update function, not here.
+        size_t base_tile = sequence_synth[i].note;
+        seq_sprites[i].obj_attr_2 = base_tile;
+
+        OBJ_ATTR_0(id) = seq_sprites[i].obj_attr_0;
+        OBJ_ATTR_1(id) = seq_sprites[i].obj_attr_1;
+        OBJ_ATTR_2(id) = seq_sprites[i].obj_attr_2;
+    }
+}