public static int stbtt__solve_cubic(float a, float b, float c, float *r)
{
float s = -a / 3;
float p = b - a * a / 3;
float q = a * (2 * a * a - 9 * b) / 27 + c;
float p3 = p * p * p;
float d = q * q + 4 * p3 / 27;
if ((d) >= (0))
{
float z = (float)(CRuntime.Sqrt(d));
float u = (-q + z) / 2;
float v = (-q - z) / 2;
u = stbtt__cuberoot(u);
v = stbtt__cuberoot(v);
r[0] = s + u + v;
return(1);
}
else
{
float u = (float)(CRuntime.Sqrt(-p / 3));
float v = (float)(CRuntime.Acos(-CRuntime.Sqrt(-27 / p3) * q / 2)) / 3;
float m = (float)(CRuntime.Cos(v));
float n = (float)(CRuntime.Cos(v - 3.141592 / 2)) * 1.732050808f;
r[0] = s + u * 2 * m;
r[1] = s - u * (m + n);
r[2] = s - u * (m - n);
return(3);
}
}
