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// Simple low-pass and high-pass filter to better match sound output of a SNES
// Game_Music_Emu 0.5.5
#ifndef SPC_FILTER_H
#define SPC_FILTER_H
#include "blargg_common.h"
struct SPC_Filter {
public:
// Filters count samples of stereo sound in place. Count must be a multiple of 2.
typedef short sample_t;
void run( sample_t* io, int count );
// Optional features
// Clears filter to silence
void clear();
// Sets gain (volume), where gain_unit is normal. Gains greater than gain_unit
// are fine, since output is clamped to 16-bit sample range.
enum { gain_unit = 0x100 };
void set_gain( int gain );
// Enables/disables filtering (when disabled, gain is still applied)
void enable( bool b );
// Sets amount of bass (logarithmic scale)
enum { bass_none = 0 };
enum { bass_norm = 8 }; // normal amount
enum { bass_max = 31 };
void set_bass( int bass );
public:
SPC_Filter();
BLARGG_DISABLE_NOTHROW
private:
enum { gain_bits = 8 };
int gain;
int bass;
bool enabled;
struct chan_t { int p1, pp1, sum; };
chan_t ch [2];
};
inline void SPC_Filter::enable( bool b ) { enabled = b; }
inline void SPC_Filter::set_gain( int g ) { gain = g; }
inline void SPC_Filter::set_bass( int b ) { bass = b; }
#endif
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