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/gme/Gb_Apu.h

http://game-music-emu.googlecode.com/
C++ Header | 90 lines | 50 code | 22 blank | 18 comment | 0 complexity | dd9bc00345dbdacedd5473b2c2476f86 MD5 | raw file
 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
 9class Gb_Apu {
10public:
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	
53public:
54	Gb_Apu();
55private:
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
80inline void Gb_Apu::output( Blip_Buffer* b ) { output( b, b, b ); }
81	
82inline void Gb_Apu::osc_output( int i, Blip_Buffer* b ) { osc_output( i, b, b, b ); }
83
84inline 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