mirror of
https://github.com/thestk/stk
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63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
/*******************************************/
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/* One Pole Filter Class, */
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/* by Perry R. Cook, 1995-96 */
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/* The parameter gain is an additional */
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/* gain parameter applied to the filter */
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/* on top of the normalization that takes */
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/* place automatically. So the net max */
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/* gain through the system equals the */
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/* value of gain. sgain is the combina- */
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/* tion of gain and the normalization */
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/* parameter, so if you set the poleCoeff */
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/* to alpha, sgain is always set to */
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/* gain * (1.0 - fabs(alpha)). */
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/*******************************************/
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#include "OnePole.h"
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OnePole :: OnePole() : Filter()
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{
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poleCoeff = (MY_FLOAT) 0.9;
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gain = (MY_FLOAT) 1.0;
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sgain = (MY_FLOAT) 0.1;
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outputs = (MY_FLOAT *) malloc(sizeof(MY_FLOAT));
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outputs[0] = (MY_FLOAT) 0.0;
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}
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OnePole :: ~OnePole()
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{
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free(outputs);
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}
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void OnePole :: clear()
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{
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outputs[0] = (MY_FLOAT) 0.0;
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lastOutput = (MY_FLOAT) 0.0;
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}
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void OnePole :: setPole(MY_FLOAT aValue)
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{
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poleCoeff = aValue;
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if (poleCoeff > 0.0) // Normalize gain to 1.0 max
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sgain = gain * ((MY_FLOAT) 1.0 - poleCoeff);
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else
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sgain = gain * ((MY_FLOAT) 1.0 + poleCoeff);
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}
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void OnePole :: setGain(MY_FLOAT aValue)
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{
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gain = aValue;
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if (poleCoeff > 0.0)
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sgain = gain * ((MY_FLOAT) 1.0 - poleCoeff); // Normalize gain to 1.0 max
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else
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sgain = gain * ((MY_FLOAT) 1.0 + poleCoeff);
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}
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MY_FLOAT OnePole :: tick(MY_FLOAT sample) // Perform Filter Operation
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{
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outputs[0] = (sgain * sample) + (poleCoeff * outputs[0]);
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lastOutput = outputs[0];
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return lastOutput;
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}
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