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https://github.com/thestk/stk
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67 lines
2.0 KiB
C++
67 lines
2.0 KiB
C++
/**********************************************/
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/* Lip Filter Object by Perry R. Cook, 1995-96*/
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/* The lip of the brass player has dynamics */
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/* which are controlled by the mass, spring */
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/* constant, and damping of the lip. This */
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/* filter simulates that behavior and the */
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/* transmission/reflection properties as */
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/* well. See Cook TBone and HosePlayer */
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/* instruments and articles. */
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/**********************************************/
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#include "LipFilt.h"
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LipFilt :: LipFilt()
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{
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MY_FLOAT coeffs[2];
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filter = new BiQuad;
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coeffs[0] = 0.0;
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coeffs[1] = 0.0;
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filter->setZeroCoeffs(coeffs);
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this->clear();
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}
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LipFilt :: ~LipFilt()
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{
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delete filter;
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}
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void LipFilt :: clear()
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{
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filter->clear();
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lastOutput = 0.0;
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}
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void LipFilt :: setFreq(MY_FLOAT frequency)
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{
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MY_FLOAT coeffs[2];
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coeffs[0] = 2.0 * 0.997 *
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cos(TWO_PI * frequency / SRATE); /* damping should change with */
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coeffs[1] = -0.997 * 0.997; /* lip parameters, but not yet.*/
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filter->setPoleCoeffs(coeffs);
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filter->setGain(0.03);
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}
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/* NOTE: Here we should add lip tension */
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/* settings based on Mass/Spring/Damping */
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/* Maybe in TookKit97 */
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MY_FLOAT LipFilt :: tick(MY_FLOAT mouthSample,MY_FLOAT boreSample)
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/* Perform "Table Lookup" By Polynomial Calculation */
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{
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MY_FLOAT temp;
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temp = mouthSample - boreSample; /* Differential pressure */
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temp = filter->tick(temp); /* Force -> position */
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temp = temp*temp; /* Simple position to area mapping */
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if (temp > 1.0) temp = 1.0; /* Saturation at + 1.0 */
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lastOutput = temp * mouthSample; /* Assume mouth input = area */
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lastOutput += (1.0 - temp) * boreSample; /* and Bore reflection is compliment. */
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return lastOutput;
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}
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MY_FLOAT LipFilt :: lastOut()
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{
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return lastOutput;
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}
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