Function blackman

KeyboardVisualizerCommon/chuck_fft.c:64–77

----------------------------------------------------------------------------- name: blackman() desc: make window -----------------------------------------------------------------------------

// desc: make window
//-----------------------------------------------------------------------------
void blackman(float * window, unsigned long length)
{
    unsigned long i;
    double pi, phase = 0, delta;

    pi = 4.*atan(1.0);
    delta = 2 * pi / (double)length;

    for (i = 0; i < length; i++)
    {
        window[i] = (float)(0.42 - .5*cos(phase) + .08*cos(2 * phase));
        phase += delta;
    }
}