public SphericalRoundBullet(XY offset0, float z0, float r, XY v, XY o0)
{
__v = v;
__angle0 = Mathf.Atan2(z0, offset0.X);
var axisOffset = XY.Project(offset0, v.Rotated90CW());
__offset = o0 + axisOffset;
__r = Mathf.Sqrt(r * r - axisOffset.SqrLength);
BorderColor = Color.Red;
MainColor = Color.Red;
R = 5;
}