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