mx_dodge_float.osl

void mx_dodge_float(float fg, float bg, float mix, output float out)
{
    if (abs(1.0 - fg) < M_FLOAT_EPS)
    {
        out = 0.0;
        return;
    }
    out = mix*(bg / (1.0 - fg)) + ((1.0-mix)*bg);
}