100 lines
2.0 KiB
C
100 lines
2.0 KiB
C
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// Konami VRC6 sound chip emulator
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// Nes_Snd_Emu 0.1.7
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#ifndef NES_VRC6_APU_H
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#define NES_VRC6_APU_H
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#include <stdint.h>
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#include "Nes_Apu.h"
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#include "Blip_Buffer.h"
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struct vrc6_apu_state_t;
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class Nes_Vrc6_Apu {
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public:
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Nes_Vrc6_Apu();
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~Nes_Vrc6_Apu();
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// See Nes_Apu.h for reference
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void reset();
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void volume( double );
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void treble_eq( blip_eq_t const& );
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void output( Blip_Buffer* );
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enum { osc_count = 3 };
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void osc_output( int index, Blip_Buffer* );
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void end_frame( nes_time_t );
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void save_state( vrc6_apu_state_t* ) const;
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void load_state( vrc6_apu_state_t const& );
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// Oscillator 0 write-only registers are at $9000-$9002
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// Oscillator 1 write-only registers are at $A000-$A002
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// Oscillator 2 write-only registers are at $B000-$B002
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enum { reg_count = 3 };
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enum { base_addr = 0x9000 };
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enum { addr_step = 0x1000 };
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void write_osc( nes_time_t, int osc, int reg, int data );
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private:
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// noncopyable
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Nes_Vrc6_Apu( const Nes_Vrc6_Apu& );
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Nes_Vrc6_Apu& operator = ( const Nes_Vrc6_Apu& );
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struct Vrc6_Osc
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{
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uint8_t regs [3];
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Blip_Buffer* output;
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int delay;
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int last_amp;
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int phase;
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int amp; // only used by saw
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int period() const
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{
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return (regs [2] & 0x0f) * 0x100L + regs [1] + 1;
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}
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};
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Vrc6_Osc oscs [osc_count];
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nes_time_t last_time;
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Blip_Synth<blip_med_quality,1> saw_synth;
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Blip_Synth<blip_good_quality,1> square_synth;
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void run_until( nes_time_t );
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void run_square( Vrc6_Osc& osc, nes_time_t );
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void run_saw( nes_time_t );
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};
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struct vrc6_apu_state_t
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{
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uint8_t regs [3] [3];
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uint8_t saw_amp;
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uint16_t delays [3];
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uint8_t phases [3];
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uint8_t unused;
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};
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BOOST_STATIC_ASSERT( sizeof (vrc6_apu_state_t) == 20 );
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inline void Nes_Vrc6_Apu::osc_output( int i, Blip_Buffer* buf )
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{
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oscs [i].output = buf;
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}
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inline void Nes_Vrc6_Apu::volume( double v )
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{
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double const factor = 0.0967 * 2;
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saw_synth.volume( factor / 31 * v );
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square_synth.volume( factor * 0.5 / 15 * v );
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}
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inline void Nes_Vrc6_Apu::treble_eq( blip_eq_t const& eq )
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{
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saw_synth.treble_eq( eq );
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square_synth.treble_eq( eq );
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}
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#endif
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