mirror of https://github.com/snes9xgit/snes9x.git
48 lines
1.0 KiB
C
48 lines
1.0 KiB
C
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// Simple low-pass and high-pass filter to better match sound output of a SNES
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// snes_spc 0.9.0
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#ifndef SPC_FILTER_H
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#define SPC_FILTER_H
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#include "blargg_common.h"
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struct SPC_Filter {
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public:
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// Filters count samples of stereo sound in place. Count must be a multiple of 2.
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typedef short sample_t;
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void run( sample_t* io, int count );
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// Optional features
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// Clears filter to silence
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void clear();
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// Sets gain (volume), where gain_unit is normal. Gains greater than gain_unit
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// are fine, since output is clamped to 16-bit sample range.
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enum { gain_unit = 0x100 };
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void set_gain( int gain );
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// Sets amount of bass (logarithmic scale)
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enum { bass_none = 0 };
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enum { bass_norm = 8 }; // normal amount
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enum { bass_max = 31 };
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void set_bass( int bass );
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public:
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SPC_Filter();
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BLARGG_DISABLE_NOTHROW
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private:
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enum { gain_bits = 8 };
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int gain;
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int bass;
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struct chan_t { int p1, pp1, sum; };
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chan_t ch [2];
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};
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inline void SPC_Filter::set_gain( int g ) { gain = g; }
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inline void SPC_Filter::set_bass( int b ) { bass = b; }
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#endif
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