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#include <string.h>
#include "common.h"
#include "gba-buttons.c"
#include "background-tiles.c"
#include "sprites.h"
#include "text.h"
//
// Main functions.
//
// TODO: Cleanup OBJ/OAM memory copying and access.
//
typedef struct SeqTrigger {
bool trigger;
Note note;
// TODO: ...
} SeqTrigger;
static SeqTrigger sequence_synth_1 [] = {
{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},
};
int step_counter = 0;
Note active_note;
void
irq_timer_0(void) {
active_note = sequence_synth_1[step_counter].note;
if (sequence_synth_1[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) {
// TIMER_CTRL_0 = TIMER_CTRL_DISABLE;
// 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;
}
int main(void) {
// Configure the display in mode 0 to show OBJs, where tile memory is
// sequential.
DISP_CTRL = DISP_ENABLE_SPRITES | DISP_MODE_0 | DISP_BG_0;
// Initialize sprite button overlay.
init_sprite_pal(0, COLOR_WHITE);
init_sprites(0);
init_button_sprites();
// Initialize text engine.
txt_init(0, COLOR_RED, 0);
// Register interrupts.
irq_init();
irs_set(IRQ_VBLANK, irs_stub);
// turn sound on
SOUND_STATUS = SOUND_ENABLE;
SOUND_DMG_MASTER = sound_volume(SOUND_SQUARE1 | SOUND_SQUARE2, 7);
SOUND_DSOUND_MASTER = SOUND_DMG100;
// Initialize timer.
int bpm = 120;
while(true) {
bios_vblank_wait();
poll_keys();
if (key_hold(KEY_UP)) {
bpm += 1;
set_time(bpm);
}
if (key_hold(KEY_DOWN)) {
bpm -= 1;
set_time(bpm);
}
if (key_pressed(KEY_START)) {
step_counter = 0;
set_time(bpm);
}
if (key_pressed(KEY_SELECT)) {
TIMER_CTRL_0 ^= TIMER_CTRL_ENABLE;
}
txt_position(1,6);
txt_clear_line();
txt_printf(" BPM: %d\n\n", bpm);
txt_clear_line();
txt_printf(" Step: %d\n", step_counter);
txt_clear_line();
txt_printf(" Note: %s\n", note_names[active_note]);
update_button_sprites();
};
return 0;
}
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