1 // Nintendo Game Boy PAPU sound chip emulator
2
3 // Gb_Snd_Emu 0.1.5
4 #ifndef GB_APU_H
5 #define GB_APU_H
6
7 #include "Gb_Oscs.h"
8
9 class Gb_Apu {
10 public:
11
12 // Set overall volume of all oscillators, where 1.0 is full volume
13 void volume( double );
14
15 // Set treble equalization
16 void treble_eq( const blip_eq_t& );
17
18 // Outputs can be assigned to a single buffer for mono output, or to three
19 // buffers for stereo output (using Stereo_Buffer to do the mixing).
20
21 // Assign all oscillator outputs to specified buffer(s). If buffer
22 // is NULL, silences all oscillators.
23 void output( Blip_Buffer* mono );
24 void output( Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
25
26 // Assign single oscillator output to buffer(s). Valid indicies are 0 to 3,
27 // which refer to Square 1, Square 2, Wave, and Noise. If buffer is NULL,
28 // silences oscillator.
29 enum { osc_count = 4 };
30 void osc_output( int index, Blip_Buffer* mono );
31 void osc_output( int index, Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
32
33 // Reset oscillators and internal state
34 void reset();
35
36 // Reads and writes at addr must satisfy start_addr <= addr <= end_addr
37 enum { start_addr = 0xFF10 };
38 enum { end_addr = 0xFF3F };
39 enum { register_count = end_addr - start_addr + 1 };
40
41 // Write 'data' to address at specified time
42 void write_register( blip_time_t, unsigned addr, int data );
43
44 // Read from address at specified time
45 int read_register( blip_time_t, unsigned addr );
46
47 // Run all oscillators up to specified time, end current time frame, then
48 // start a new frame at time 0.
49 void end_frame( blip_time_t );
50
51 void set_tempo( double );
52
53 public:
54 Gb_Apu();
55 private:
56 // noncopyable
57 Gb_Apu( const Gb_Apu& );
58 Gb_Apu& operator = ( const Gb_Apu& );
59
60 Gb_Osc* oscs [osc_count];
61 blip_time_t next_frame_time;
62 blip_time_t last_time;
63 blip_time_t frame_period;
64 double volume_unit;
65 int frame_count;
66
67 Gb_Square square1;
68 Gb_Square square2;
69 Gb_Wave wave;
70 Gb_Noise noise;
71 BOOST::uint8_t regs [register_count];
72 Gb_Square::Synth square_synth; // used by squares
73 Gb_Wave::Synth other_synth; // used by wave and noise
74
75 void update_volume();
76 void run_until( blip_time_t );
77 void write_osc( int index, int reg, int data );
78 };
79
output(Blip_Buffer * b)80 inline void Gb_Apu::output( Blip_Buffer* b ) { output( b, b, b ); }
81
osc_output(int i,Blip_Buffer * b)82 inline void Gb_Apu::osc_output( int i, Blip_Buffer* b ) { osc_output( i, b, b, b ); }
83
volume(double vol)84 inline void Gb_Apu::volume( double vol )
85 {
86 volume_unit = 0.60 / osc_count / 15 /*steps*/ / 2 /*?*/ / 8 /*master vol range*/ * vol;
87 update_volume();
88 }
89
90 #endif
91