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-rw-r--r--Alc/filters/biquad.cpp127
1 files changed, 0 insertions, 127 deletions
diff --git a/Alc/filters/biquad.cpp b/Alc/filters/biquad.cpp
deleted file mode 100644
index 6a3cef64..00000000
--- a/Alc/filters/biquad.cpp
+++ /dev/null
@@ -1,127 +0,0 @@
-
-#include "config.h"
-
-#include "biquad.h"
-
-#include <algorithm>
-#include <cassert>
-#include <cmath>
-
-#include "opthelpers.h"
-
-
-template<typename Real>
-void BiquadFilterR<Real>::setParams(BiquadType type, Real gain, Real f0norm, Real rcpQ)
-{
- // Limit gain to -100dB
- assert(gain > 0.00001f);
-
- const Real w0{al::MathDefs<Real>::Tau() * f0norm};
- const Real sin_w0{std::sin(w0)};
- const Real cos_w0{std::cos(w0)};
- const Real alpha{sin_w0/2.0f * rcpQ};
-
- Real sqrtgain_alpha_2;
- Real a[3]{ 1.0f, 0.0f, 0.0f };
- Real b[3]{ 1.0f, 0.0f, 0.0f };
-
- /* Calculate filter coefficients depending on filter type */
- switch(type)
- {
- case BiquadType::HighShelf:
- sqrtgain_alpha_2 = 2.0f * std::sqrt(gain) * alpha;
- b[0] = gain*((gain+1.0f) + (gain-1.0f)*cos_w0 + sqrtgain_alpha_2);
- b[1] = -2.0f*gain*((gain-1.0f) + (gain+1.0f)*cos_w0 );
- b[2] = gain*((gain+1.0f) + (gain-1.0f)*cos_w0 - sqrtgain_alpha_2);
- a[0] = (gain+1.0f) - (gain-1.0f)*cos_w0 + sqrtgain_alpha_2;
- a[1] = 2.0f* ((gain-1.0f) - (gain+1.0f)*cos_w0 );
- a[2] = (gain+1.0f) - (gain-1.0f)*cos_w0 - sqrtgain_alpha_2;
- break;
- case BiquadType::LowShelf:
- sqrtgain_alpha_2 = 2.0f * std::sqrt(gain) * alpha;
- b[0] = gain*((gain+1.0f) - (gain-1.0f)*cos_w0 + sqrtgain_alpha_2);
- b[1] = 2.0f*gain*((gain-1.0f) - (gain+1.0f)*cos_w0 );
- b[2] = gain*((gain+1.0f) - (gain-1.0f)*cos_w0 - sqrtgain_alpha_2);
- a[0] = (gain+1.0f) + (gain-1.0f)*cos_w0 + sqrtgain_alpha_2;
- a[1] = -2.0f* ((gain-1.0f) + (gain+1.0f)*cos_w0 );
- a[2] = (gain+1.0f) + (gain-1.0f)*cos_w0 - sqrtgain_alpha_2;
- break;
- case BiquadType::Peaking:
- gain = std::sqrt(gain);
- b[0] = 1.0f + alpha * gain;
- b[1] = -2.0f * cos_w0;
- b[2] = 1.0f - alpha * gain;
- a[0] = 1.0f + alpha / gain;
- a[1] = -2.0f * cos_w0;
- a[2] = 1.0f - alpha / gain;
- break;
-
- case BiquadType::LowPass:
- b[0] = (1.0f - cos_w0) / 2.0f;
- b[1] = 1.0f - cos_w0;
- b[2] = (1.0f - cos_w0) / 2.0f;
- a[0] = 1.0f + alpha;
- a[1] = -2.0f * cos_w0;
- a[2] = 1.0f - alpha;
- break;
- case BiquadType::HighPass:
- b[0] = (1.0f + cos_w0) / 2.0f;
- b[1] = -(1.0f + cos_w0);
- b[2] = (1.0f + cos_w0) / 2.0f;
- a[0] = 1.0f + alpha;
- a[1] = -2.0f * cos_w0;
- a[2] = 1.0f - alpha;
- break;
- case BiquadType::BandPass:
- b[0] = alpha;
- b[1] = 0.0f;
- b[2] = -alpha;
- a[0] = 1.0f + alpha;
- a[1] = -2.0f * cos_w0;
- a[2] = 1.0f - alpha;
- break;
- }
-
- a1 = a[1] / a[0];
- a2 = a[2] / a[0];
- b0 = b[0] / a[0];
- b1 = b[1] / a[0];
- b2 = b[2] / a[0];
-}
-
-template<typename Real>
-void BiquadFilterR<Real>::process(Real *dst, const Real *src, int numsamples)
-{
- ASSUME(numsamples > 0);
-
- const Real b0{this->b0};
- const Real b1{this->b1};
- const Real b2{this->b2};
- const Real a1{this->a1};
- const Real a2{this->a2};
- Real z1{this->z1};
- Real z2{this->z2};
-
- /* Processing loop is Transposed Direct Form II. This requires less storage
- * compared to Direct Form I (only two delay components, instead of a four-
- * sample history; the last two inputs and outputs), and works better for
- * floating-point which favors summing similarly-sized values while being
- * less bothered by overflow.
- *
- * See: http://www.earlevel.com/main/2003/02/28/biquads/
- */
- auto proc_sample = [b0,b1,b2,a1,a2,&z1,&z2](Real input) noexcept -> Real
- {
- Real output = input*b0 + z1;
- z1 = input*b1 - output*a1 + z2;
- z2 = input*b2 - output*a2;
- return output;
- };
- std::transform(src, src+numsamples, dst, proc_sample);
-
- this->z1 = z1;
- this->z2 = z2;
-}
-
-template class BiquadFilterR<float>;
-template class BiquadFilterR<double>;