The Synthesis ToolKit in C++ (STK)

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BiQuad.h
1#ifndef STK_BIQUAD_H
2#define STK_BIQUAD_H
3
4#include "Filter.h"
5
6namespace stk {
7
8/***************************************************/
18/***************************************************/
19
20 class BiQuad : public Filter
21{
22public:
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
stk::BiQuad
STK biquad (two-pole, two-zero) filter class.
Definition: BiQuad.h:21
stk::BiQuad::setA1
void setA1(StkFloat a1)
Set the a[1] coefficient value.
Definition: BiQuad.h:46
stk::BiQuad::setB2
void setB2(StkFloat b2)
Set the b[2] coefficient value.
Definition: BiQuad.h:43
stk::BiQuad::setB0
void setB0(StkFloat b0)
Set the b[0] coefficient value.
Definition: BiQuad.h:37
stk::BiQuad::setEqualGainZeroes
void setEqualGainZeroes(void)
Sets the filter zeroes for equal resonance gain.
stk::BiQuad::setResonance
void setResonance(StkFloat frequency, StkFloat radius, bool normalize=false)
Sets the filter coefficients for a resonance at frequency (in Hz).
stk::BiQuad::tick
StkFloat tick(StkFloat input)
Input one sample to the filter and return a reference to one output.
Definition: BiQuad.h:119
stk::BiQuad::BiQuad
BiQuad()
Default constructor creates a second-order pass-through filter.
stk::BiQuad::ignoreSampleRateChange
void ignoreSampleRateChange(bool ignore=true)
A function to enable/disable the automatic updating of class data when the STK sample rate changes.
Definition: BiQuad.h:31
stk::BiQuad::lastOut
StkFloat lastOut(void) const
Return the last computed output value.
Definition: BiQuad.h:87
stk::BiQuad::~BiQuad
~BiQuad()
Class destructor.
stk::BiQuad::setB1
void setB1(StkFloat b1)
Set the b[1] coefficient value.
Definition: BiQuad.h:40
stk::BiQuad::setNotch
void setNotch(StkFloat frequency, StkFloat radius)
Set the filter coefficients for a notch at frequency (in Hz).
stk::BiQuad::setA2
void setA2(StkFloat a2)
Set the a[2] coefficient value.
Definition: BiQuad.h:49
stk::BiQuad::setCoefficients
void setCoefficients(StkFloat b0, StkFloat b1, StkFloat b2, StkFloat a1, StkFloat a2, bool clearState=false)
Set all filter coefficients.
stk::Filter
STK abstract filter class.
Definition: Filter.h:23
stk::StkFrames
An STK class to handle vectorized audio data.
Definition: Stk.h:279
stk::StkFrames::channels
unsigned int channels(void) const
Return the number of channels represented by the data.
Definition: Stk.h:416
stk::StkFrames::frames
unsigned int frames(void) const
Return the number of sample frames represented by the data.
Definition: Stk.h:419
stk::Stk::handleError
static void handleError(const char *message, StkError::Type type)
Static function for error reporting and handling using c-strings.
stk
The STK namespace.
Definition: ADSR.h:6

The Synthesis ToolKit in C++ (STK)
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