Gb_Oscs.h

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// Private oscillators used by Gb_Apu
 
// Gb_Snd_Emu 0.1.5
#ifndef GB_OSCS_H
#define GB_OSCS_H
 
#include "blargg_common.h"
#include "Blip_Buffer.h"
 
struct Gb_Osc
{
        enum { trigger = 0x80 };
        enum { len_enabled_mask = 0x40 };
        
        Blip_Buffer* outputs [4]; // NULL, right, left, center
        Blip_Buffer* output;
        int output_select;
        uint8_t* regs; // osc's 5 registers
        
        int delay;
        int last_amp;
        int volume;
        int length;
        int enabled;
        
        void reset();
        void clock_length();
        int frequency() const { return (regs [4] & 7) * 0x100 + regs [3]; }
};
 
struct Gb_Env : Gb_Osc
{
        int env_delay;
        
        void reset();
        void clock_envelope();
        bool write_register( int, int );
};
 
struct Gb_Square : Gb_Env
{
        enum { period_mask = 0x70 };
        enum { shift_mask  = 0x07 };
        
        typedef Blip_Synth<blip_good_quality,1> Synth;
        Synth const* synth;
        int sweep_delay;
        int sweep_freq;
        int phase;
        
        void reset();
        void clock_sweep();
        void run( blip_time_t, blip_time_t, int playing );
};
 
struct Gb_Noise : Gb_Env
{
        typedef Blip_Synth<blip_med_quality,1> Synth;
        Synth const* synth;
        unsigned bits;
        
        void run( blip_time_t, blip_time_t, int playing );
};
 
struct Gb_Wave : Gb_Osc
{
        typedef Blip_Synth<blip_med_quality,1> Synth;
        Synth const* synth;
        int wave_pos;
        enum { wave_size = 32 };
        uint8_t wave [wave_size];
        
        void write_register( int, int );
        void run( blip_time_t, blip_time_t, int playing );
};
 
inline void Gb_Env::reset()
{
        env_delay = 0;
        Gb_Osc::reset();
}
 
#endif