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BiQuad.h
1 #ifndef STK_BIQUAD_H
2 #define STK_BIQUAD_H
3
4 #include "Filter.h"
5
6 namespace stk {
7
8 /***************************************************/
18 /***************************************************/
19
20 class BiQuad : public Filter
21 {
22 public:
23
25 BiQuad();
26
28 ~BiQuad();
29
31 void ignoreSampleRateChange( bool ignore = true ) { ignoreSampleRateChange_ = ignore; };
32
34 void setCoefficients( StkFloat b0, StkFloat b1, StkFloat b2, StkFloat a1, StkFloat a2, bool clearState = false );
35
37 void setB0( StkFloat b0 ) { b_[0] = b0; };
38
40 void setB1( StkFloat b1 ) { b_[1] = b1; };
41
43 void setB2( StkFloat b2 ) { b_[2] = b2; };
44
46 void setA1( StkFloat a1 ) { a_[1] = a1; };
47
49 void setA2( StkFloat a2 ) { a_[2] = a2; };
50
52
65 void setResonance( StkFloat frequency, StkFloat radius, bool normalize = false );
66
68
75 void setNotch( StkFloat frequency, StkFloat radius );
76
78
84 void setEqualGainZeroes( void );
85
87 StkFloat lastOut( void ) const { return lastFrame_[0]; };
88
90 StkFloat tick( StkFloat input );
91
93
101 StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
102
104
112 StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
113
114 protected:
115
116 virtual void sampleRateChanged( StkFloat newRate, StkFloat oldRate );
117 };
118
119 inline StkFloat BiQuad :: tick( StkFloat input )
120 {
121 inputs_[0] = gain_ * input;
122 lastFrame_[0] = b_[0] * inputs_[0] + b_[1] * inputs_[1] + b_[2] * inputs_[2];
123 lastFrame_[0] -= a_[2] * outputs_[2] + a_[1] * outputs_[1];
124 inputs_[2] = inputs_[1];
125 inputs_[1] = inputs_[0];
126 outputs_[2] = outputs_[1];
127 outputs_[1] = lastFrame_[0];
128
129 return lastFrame_[0];
130 }
131
132 inline StkFrames& BiQuad :: tick( StkFrames& frames, unsigned int channel )
133 {
134 #if defined(_STK_DEBUG_)
135 if ( channel >= frames.channels() ) {
136 oStream_ << "BiQuad::tick(): channel and StkFrames arguments are incompatible!";
137 handleError( StkError::FUNCTION_ARGUMENT );
138 }
139 #endif
140
141 StkFloat *samples = &frames[channel];
142 unsigned int hop = frames.channels();
143 for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
144 inputs_[0] = gain_ * *samples;
145 *samples = b_[0] * inputs_[0] + b_[1] * inputs_[1] + b_[2] * inputs_[2];
146 *samples -= a_[2] * outputs_[2] + a_[1] * outputs_[1];
147 inputs_[2] = inputs_[1];
148 inputs_[1] = inputs_[0];
149 outputs_[2] = outputs_[1];
150 outputs_[1] = *samples;
151 }
152
153 lastFrame_[0] = outputs_[1];
154 return frames;
155 }
156
157 inline StkFrames& BiQuad :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
158 {
159 #if defined(_STK_DEBUG_)
160 if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
161 oStream_ << "BiQuad::tick(): channel and StkFrames arguments are incompatible!";
162 handleError( StkError::FUNCTION_ARGUMENT );
163 }
164 #endif
165
166 StkFloat *iSamples = &iFrames[iChannel];
167 StkFloat *oSamples = &oFrames[oChannel];
168 unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
169 for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
170 inputs_[0] = gain_ * *iSamples;
171 *oSamples = b_[0] * inputs_[0] + b_[1] * inputs_[1] + b_[2] * inputs_[2];
172 *oSamples -= a_[2] * outputs_[2] + a_[1] * outputs_[1];
173 inputs_[2] = inputs_[1];
174 inputs_[1] = inputs_[0];
175 outputs_[2] = outputs_[1];
176 outputs_[1] = *oSamples;
177 }
178
179 lastFrame_[0] = outputs_[1];
180 return iFrames;
181 }
182
183 } // stk namespace
184
185 #endif
186

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