#define M_PI		3.141592653f
#define M_PI_ON_2	(M_PI / 2.f)
#define M_PI_ON_4	(M_PI / 4.f)
#define M_FLT_EPSILON FLT_MIN

// Assuming you've adjusted pos to be relative to the origin of the radar and its values are float integers (cause pixels)
void SquareRadarClamp(float Length, Vector2D &pos)
{
	float LenSqr = pos.LengthSqr();

	if (LenSqr <= (Length * Length * 0.5f))
		return;

	float angle = atan2(pos.y, pos.x);

	float radius = cos(M_PI_ON_4) / cos(fmodf(angle + M_PI_ON_4, M_PI_ON_2) - M_PI_ON_4);

	if (LenSqr <= (radius * radius))
		return;

	pos *= (Length * 0.5f) / (radius + M_FLT_EPSILON);
}