280 lines
8.7 KiB
C++
280 lines
8.7 KiB
C++
#pragma once
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#define _USE_MATH_DEFINES
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#include <array>
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#include <math.h>
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#include <stdint.h>
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namespace trnr {
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template <typename t_sample>
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// Lowpass filter based on YLowpass by Chris Johnson
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class ylowpass {
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public:
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ylowpass(double _samplerate)
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: samplerate {_samplerate}
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, A {0.1f}
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, B {1.0f}
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, C {0.0f}
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, D {0.1f}
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, E {0.9f}
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, F {1.0f}
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, fpdL {0}
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, fpdR {0}
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, biquad {0}
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{
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for (int x = 0; x < biq_total; x++) { biquad[x] = 0.0; }
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powFactorA = 1.0;
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powFactorB = 1.0;
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inTrimA = 0.1;
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inTrimB = 0.1;
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outTrimA = 1.0;
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outTrimB = 1.0;
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for (int x = 0; x < fix_total; x++) {
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fixA[x] = 0.0;
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fixB[x] = 0.0;
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}
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fpdL = 1.0;
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while (fpdL < 16386) fpdL = rand() * UINT32_MAX;
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fpdR = 1.0;
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while (fpdR < 16386) fpdR = rand() * UINT32_MAX;
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}
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void set_samplerate(double _samplerate) { samplerate = _samplerate; }
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void set_drive(float value) { A = value * 0.9 + 0.1; }
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void set_frequency(float value) { B = value; }
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void set_resonance(float value) { C = value; }
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void set_edge(float value) { D = value; }
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void set_output(float value) { E = value; }
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void set_mix(float value) { F = value; }
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void processblock(t_sample** inputs, t_sample** outputs, int blockSize)
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{
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t_sample* in1 = inputs[0];
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t_sample* in2 = inputs[1];
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t_sample* out1 = outputs[0];
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t_sample* out2 = outputs[1];
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int inFramesToProcess = blockSize;
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double overallscale = 1.0;
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overallscale /= 44100.0;
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overallscale *= samplerate;
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inTrimA = inTrimB;
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inTrimB = A * 10.0;
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biquad[biq_freq] = pow(B, 3) * 20000.0;
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if (biquad[biq_freq] < 15.0) biquad[biq_freq] = 15.0;
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biquad[biq_freq] /= samplerate;
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biquad[biq_reso] = (pow(C, 2) * 15.0) + 0.5571;
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biquad[biq_aA0] = biquad[biq_aB0];
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biquad[biq_aA1] = biquad[biq_aB1];
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biquad[biq_aA2] = biquad[biq_aB2];
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biquad[biq_bA1] = biquad[biq_bB1];
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biquad[biq_bA2] = biquad[biq_bB2];
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// previous run through the buffer is still in the filter, so we move it
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// to the A section and now it's the new starting point.
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double K = tan(M_PI * biquad[biq_freq]);
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double norm = 1.0 / (1.0 + K / biquad[biq_reso] + K * K);
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biquad[biq_aB0] = K * K * norm;
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biquad[biq_aB1] = 2.0 * biquad[biq_aB0];
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biquad[biq_aB2] = biquad[biq_aB0];
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biquad[biq_bB1] = 2.0 * (K * K - 1.0) * norm;
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biquad[biq_bB2] = (1.0 - K / biquad[biq_reso] + K * K) * norm;
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// for the coefficient-interpolated biquad filter
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powFactorA = powFactorB;
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powFactorB = pow(D + 0.9, 4);
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// 1.0 == target neutral
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outTrimA = outTrimB;
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outTrimB = E;
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double wet = F;
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fixA[fix_freq] = fixB[fix_freq] = 20000.0 / samplerate;
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fixA[fix_reso] = fixB[fix_reso] = 0.7071; // butterworth Q
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K = tan(M_PI * fixA[fix_freq]);
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norm = 1.0 / (1.0 + K / fixA[fix_reso] + K * K);
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fixA[fix_a0] = fixB[fix_a0] = K * K * norm;
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fixA[fix_a1] = fixB[fix_a1] = 2.0 * fixA[fix_a0];
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fixA[fix_a2] = fixB[fix_a2] = fixA[fix_a0];
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fixA[fix_b1] = fixB[fix_b1] = 2.0 * (K * K - 1.0) * norm;
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fixA[fix_b2] = fixB[fix_b2] = (1.0 - K / fixA[fix_reso] + K * K) * norm;
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// for the fixed-position biquad filter
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for (int s = 0; s < blockSize; s++) {
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double inputSampleL = *in1;
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double inputSampleR = *in2;
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if (fabs(inputSampleL) < 1.18e-23) inputSampleL = fpdL * 1.18e-17;
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if (fabs(inputSampleR) < 1.18e-23) inputSampleR = fpdR * 1.18e-17;
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double drySampleL = inputSampleL;
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double drySampleR = inputSampleR;
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double temp = (double)s / inFramesToProcess;
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biquad[biq_a0] = (biquad[biq_aA0] * temp) + (biquad[biq_aB0] * (1.0 - temp));
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biquad[biq_a1] = (biquad[biq_aA1] * temp) + (biquad[biq_aB1] * (1.0 - temp));
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biquad[biq_a2] = (biquad[biq_aA2] * temp) + (biquad[biq_aB2] * (1.0 - temp));
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biquad[biq_b1] = (biquad[biq_bA1] * temp) + (biquad[biq_bB1] * (1.0 - temp));
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biquad[biq_b2] = (biquad[biq_bA2] * temp) + (biquad[biq_bB2] * (1.0 - temp));
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// this is the interpolation code for the biquad
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double powFactor = (powFactorA * temp) + (powFactorB * (1.0 - temp));
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double inTrim = (inTrimA * temp) + (inTrimB * (1.0 - temp));
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double outTrim = (outTrimA * temp) + (outTrimB * (1.0 - temp));
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inputSampleL *= inTrim;
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inputSampleR *= inTrim;
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temp = (inputSampleL * fixA[fix_a0]) + fixA[fix_sL1];
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fixA[fix_sL1] = (inputSampleL * fixA[fix_a1]) - (temp * fixA[fix_b1]) + fixA[fix_sL2];
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fixA[fix_sL2] = (inputSampleL * fixA[fix_a2]) - (temp * fixA[fix_b2]);
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inputSampleL = temp; // fixed biquad filtering ultrasonics
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temp = (inputSampleR * fixA[fix_a0]) + fixA[fix_sR1];
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fixA[fix_sR1] = (inputSampleR * fixA[fix_a1]) - (temp * fixA[fix_b1]) + fixA[fix_sR2];
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fixA[fix_sR2] = (inputSampleR * fixA[fix_a2]) - (temp * fixA[fix_b2]);
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inputSampleR = temp; // fixed biquad filtering ultrasonics
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// encode/decode courtesy of torridgristle under the MIT license
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if (inputSampleL > 1.0) inputSampleL = 1.0;
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else if (inputSampleL > 0.0) inputSampleL = 1.0 - pow(1.0 - inputSampleL, powFactor);
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if (inputSampleL < -1.0) inputSampleL = -1.0;
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else if (inputSampleL < 0.0) inputSampleL = -1.0 + pow(1.0 + inputSampleL, powFactor);
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if (inputSampleR > 1.0) inputSampleR = 1.0;
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else if (inputSampleR > 0.0) inputSampleR = 1.0 - pow(1.0 - inputSampleR, powFactor);
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if (inputSampleR < -1.0) inputSampleR = -1.0;
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else if (inputSampleR < 0.0) inputSampleR = -1.0 + pow(1.0 + inputSampleR, powFactor);
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temp = (inputSampleL * biquad[biq_a0]) + biquad[biq_sL1];
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biquad[biq_sL1] = (inputSampleL * biquad[biq_a1]) - (temp * biquad[biq_b1]) + biquad[biq_sL2];
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biquad[biq_sL2] = (inputSampleL * biquad[biq_a2]) - (temp * biquad[biq_b2]);
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inputSampleL = temp; // coefficient interpolating biquad filter
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temp = (inputSampleR * biquad[biq_a0]) + biquad[biq_sR1];
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biquad[biq_sR1] = (inputSampleR * biquad[biq_a1]) - (temp * biquad[biq_b1]) + biquad[biq_sR2];
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biquad[biq_sR2] = (inputSampleR * biquad[biq_a2]) - (temp * biquad[biq_b2]);
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inputSampleR = temp; // coefficient interpolating biquad filter
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// encode/decode courtesy of torridgristle under the MIT license
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if (inputSampleL > 1.0) inputSampleL = 1.0;
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else if (inputSampleL > 0.0) inputSampleL = 1.0 - pow(1.0 - inputSampleL, (1.0 / powFactor));
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if (inputSampleL < -1.0) inputSampleL = -1.0;
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else if (inputSampleL < 0.0) inputSampleL = -1.0 + pow(1.0 + inputSampleL, (1.0 / powFactor));
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if (inputSampleR > 1.0) inputSampleR = 1.0;
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else if (inputSampleR > 0.0) inputSampleR = 1.0 - pow(1.0 - inputSampleR, (1.0 / powFactor));
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if (inputSampleR < -1.0) inputSampleR = -1.0;
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else if (inputSampleR < 0.0) inputSampleR = -1.0 + pow(1.0 + inputSampleR, (1.0 / powFactor));
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inputSampleL *= outTrim;
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inputSampleR *= outTrim;
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temp = (inputSampleL * fixB[fix_a0]) + fixB[fix_sL1];
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fixB[fix_sL1] = (inputSampleL * fixB[fix_a1]) - (temp * fixB[fix_b1]) + fixB[fix_sL2];
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fixB[fix_sL2] = (inputSampleL * fixB[fix_a2]) - (temp * fixB[fix_b2]);
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inputSampleL = temp; // fixed biquad filtering ultrasonics
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temp = (inputSampleR * fixB[fix_a0]) + fixB[fix_sR1];
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fixB[fix_sR1] = (inputSampleR * fixB[fix_a1]) - (temp * fixB[fix_b1]) + fixB[fix_sR2];
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fixB[fix_sR2] = (inputSampleR * fixB[fix_a2]) - (temp * fixB[fix_b2]);
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inputSampleR = temp; // fixed biquad filtering ultrasonics
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if (wet < 1.0) {
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inputSampleL = (inputSampleL * wet) + (drySampleL * (1.0 - wet));
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inputSampleR = (inputSampleR * wet) + (drySampleR * (1.0 - wet));
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}
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// begin 32 bit stereo floating point dither
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int expon;
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frexpf((float)inputSampleL, &expon);
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fpdL ^= fpdL << 13;
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fpdL ^= fpdL >> 17;
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fpdL ^= fpdL << 5;
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inputSampleL += ((double(fpdL) - uint32_t(0x7fffffff)) * 5.5e-36l * pow(2, expon + 62));
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frexpf((float)inputSampleR, &expon);
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fpdR ^= fpdR << 13;
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fpdR ^= fpdR >> 17;
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fpdR ^= fpdR << 5;
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inputSampleR += ((double(fpdR) - uint32_t(0x7fffffff)) * 5.5e-36l * pow(2, expon + 62));
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// end 32 bit stereo floating point dither
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*out1 = inputSampleL;
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*out2 = inputSampleR;
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in1++;
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in2++;
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out1++;
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out2++;
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}
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}
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private:
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double samplerate;
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enum {
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biq_freq,
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biq_reso,
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biq_a0,
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biq_a1,
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biq_a2,
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biq_b1,
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biq_b2,
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biq_aA0,
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biq_aA1,
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biq_aA2,
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biq_bA1,
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biq_bA2,
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biq_aB0,
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biq_aB1,
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biq_aB2,
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biq_bB1,
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biq_bB2,
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biq_sL1,
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biq_sL2,
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biq_sR1,
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biq_sR2,
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biq_total
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}; // coefficient interpolating biquad filter, stereo
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std::array<double, biq_total> biquad;
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double powFactorA;
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double powFactorB;
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double inTrimA;
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double inTrimB;
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double outTrimA;
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double outTrimB;
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enum {
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fix_freq,
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fix_reso,
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fix_a0,
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fix_a1,
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fix_a2,
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fix_b1,
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fix_b2,
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fix_sL1,
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fix_sL2,
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fix_sR1,
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fix_sR2,
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fix_total
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}; // fixed frequency biquad filter for ultrasonics, stereo
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std::array<double, fix_total> fixA;
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std::array<double, fix_total> fixB;
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uint32_t fpdL;
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uint32_t fpdR;
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// default stuff
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float A;
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float B;
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float C;
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float D;
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float E;
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float F; // parameters. Always 0-1, and we scale/alter them elsewhere.
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};
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} // namespace trnr
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