SameBoy/Core/apu.h

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C
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2016-03-30 20:07:55 +00:00
#ifndef apu_h
#define apu_h
#include <stdbool.h>
#include <stdint.h>
/* Divides nicely and never overflows with 4 channels */
#define MAX_CH_AMP 0x1E00
#define CH_STEP (0x1E00/0xF)
struct GB_gameboy_s;
typedef struct GB_gameboy_s GB_gameboy_t;
/* Not all used on all channels */
typedef struct
{
double phase;
double frequency;
int16_t amplitude;
int16_t start_amplitude;
double duty;
double sound_length; /* In seconds */
bool stop_on_length;
unsigned char envelope_steps;
unsigned char cur_envelope_steps;
signed int envelope_direction;
unsigned char sweep_steps;
unsigned char cur_sweep_steps;
signed int sweep_direction;
unsigned char sweep_shift;
bool is_playing;
} GB_apu_channel_t;
typedef struct
{
GB_apu_channel_t wave_channels[4];
double envelope_step_timer; /* In seconds */
double sweep_step_timer; /* In seconds */
signed char wave_form[32];
unsigned char wave_shift;
bool wave_enable;
uint16_t lfsr;
bool lfsr_7_bit;
double left_volume;
double right_volume;
bool left_on[4];
bool right_on[4];
bool global_enable;
} GB_apu_t;
void apu_render(GB_gameboy_t *gb, unsigned long sample_rate, unsigned long n_samples, int16_t *samples);
void apu_copy_buffer(GB_gameboy_t *gb, int16_t *dest, unsigned int count);
void apu_write(GB_gameboy_t *gb, unsigned char reg, unsigned char value);
unsigned char apu_read(GB_gameboy_t *gb, unsigned char reg);
void apu_init(GB_gameboy_t *gb);
void apu_copy_buffer(GB_gameboy_t *gb, int16_t *dest, unsigned int count);
void apu_run(GB_gameboy_t *gb);
#endif /* apu_h */