From 815c67f8d7dff53a6b01452ba4f485cef5744cda Mon Sep 17 00:00:00 2001 From: Peter Meerwald Date: Wed, 20 May 2015 16:55:31 +0200 Subject: [PATCH] biquad: Make use of M_SQRT2 constant should be in math.h, use it Signed-off-by: Peter Meerwald --- src/pulsecore/filter/biquad.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/src/pulsecore/filter/biquad.c b/src/pulsecore/filter/biquad.c index 7c21a29bb..4d1486446 100644 --- a/src/pulsecore/filter/biquad.c +++ b/src/pulsecore/filter/biquad.c @@ -22,6 +22,10 @@ #define M_PI 3.14159265358979323846 #endif +#ifndef M_SQRT2 +#define M_SQRT2 1.41421356237309504880 +#endif + static void set_coefficient(struct biquad *bq, double b0, double b1, double b2, double a0, double a1, double a2) { @@ -44,10 +48,8 @@ static void biquad_lowpass(struct biquad *bq, double cutoff) set_coefficient(bq, 1, 0, 0, 1, 0, 0); } else if (cutoff > 0) { /* Compute biquad coefficients for lowpass filter */ - double d = sqrt(2); - double theta = M_PI * cutoff; - double sn = 0.5 * d * sin(theta); + double sn = 0.5 * M_SQRT2 * sin(theta); double beta = 0.5 * (1 - sn) / (1 + sn); double gamma = (0.5 + beta) * cos(theta); double alpha = 0.25 * (0.5 + beta - gamma); @@ -78,10 +80,8 @@ static void biquad_highpass(struct biquad *bq, double cutoff) set_coefficient(bq, 0, 0, 0, 1, 0, 0); } else if (cutoff > 0) { /* Compute biquad coefficients for highpass filter */ - double d = sqrt(2); - double theta = M_PI * cutoff; - double sn = 0.5 * d * sin(theta); + double sn = 0.5 * M_SQRT2 * sin(theta); double beta = 0.5 * (1 - sn) / (1 + sn); double gamma = (0.5 + beta) * cos(theta); double alpha = 0.25 * (0.5 + beta + gamma);