rlm@0: // Simple low-pass and high-pass filter to better match sound output of a SNES
rlm@0: 
rlm@0: // snes_spc 0.9.0
rlm@0: #ifndef SPC_FILTER_H
rlm@0: #define SPC_FILTER_H
rlm@0: 
rlm@0: #include "blargg_common.h"
rlm@0: 
rlm@0: struct SPC_Filter {
rlm@0: public:
rlm@0: 	
rlm@0: 	// Filters count samples of stereo sound in place. Count must be a multiple of 2.
rlm@0: 	typedef short sample_t;
rlm@0: 	void run( sample_t* io, int count );
rlm@0: 	
rlm@0: // Optional features
rlm@0: 
rlm@0: 	// Clears filter to silence
rlm@0: 	void clear();
rlm@0: 
rlm@0: 	// Sets gain (volume), where gain_unit is normal. Gains greater than gain_unit
rlm@0: 	// are fine, since output is clamped to 16-bit sample range.
rlm@0: 	enum { gain_unit = 0x100 };
rlm@0: 	void set_gain( int gain );
rlm@0: 
rlm@0: 	// Sets amount of bass (logarithmic scale)
rlm@0: 	enum { bass_none =  0 };
rlm@0: 	enum { bass_norm =  8 }; // normal amount
rlm@0: 	enum { bass_max  = 31 };
rlm@0: 	void set_bass( int bass );
rlm@0: 	
rlm@0: public:
rlm@0: 	SPC_Filter();
rlm@0: 	BLARGG_DISABLE_NOTHROW
rlm@0: private:
rlm@0: 	enum { gain_bits = 8 };
rlm@0: 	int gain;
rlm@0: 	int bass;
rlm@0: 	struct chan_t { int p1, pp1, sum; };
rlm@0: 	chan_t ch [2];
rlm@0: };
rlm@0: 
rlm@0: inline void SPC_Filter::set_gain( int g ) { gain = g; }
rlm@0: 
rlm@0: inline void SPC_Filter::set_bass( int b ) { bass = b; }
rlm@0: 
rlm@0: #endif