static void filter_init(float cutoff_radians)
{
float resonance = 1.0f / sqrt(2.0f);
- float sn, cs;
- sincosf(cutoff_radians, &sn, &cs);
-
+ float sn = sin(cutoff_radians), cs = cos(cutoff_radians);
float alpha = float(sn / (2 * resonance));
// coefficients for lowpass filter
a1 = -2 * cs;
a2 = 1 - alpha;
- float invA0 = 1.0f / a0;
- b0 *= invA0;
- b1 *= invA0;
- b2 *= invA0;
- a1 *= invA0;
- a2 *= invA0;
+ b0 /= a0;
+ b1 /= a0;
+ b2 /= a0;
+ a1 /= a0;
+ a2 /= a0;
// reset filter delays
d0 = d1 = 0.0f;