public void TestCirclesIntersects()
{
//create a few circles
Circle circle1 = new Circle { Center = new Point(0, 0), Radius = 2 };
Circle circle2 = new Circle { Center = new Point(0, 0), Radius = 3 };
Circle circle3 = new Circle { Center = new Point(6, 0), Radius = 3 };
Circle circle4 = new Circle { Center = new Point(1, 1), Radius = 3 };
//non-Intersectsing circles
Assert.IsFalse(circle1.Intersects(circle3));
Assert.IsFalse(circle3.Intersects(circle1));
Assert.IsFalse(circle1.Intersects(null));
//touching circles
Assert.IsTrue(circle2.Intersects(circle3));
Assert.IsTrue(circle3.Intersects(circle2));
//Intersectsing circles
Assert.IsTrue(circle1.Intersects(circle2));
Assert.IsTrue(circle2.Intersects(circle1));
Assert.IsTrue(circle2.Intersects(circle4));
Assert.IsTrue(circle4.Intersects(circle2));
Assert.IsTrue(circle1.Intersects(circle4));
Assert.IsTrue(circle4.Intersects(circle1));
Assert.IsTrue(circle3.Intersects(circle4));
Assert.IsTrue(circle4.Intersects(circle3));
}
public bool Intersects(Circle circle)
{
//two circles intersect if the distance between the 2 centers is less than the sum of the 2 radii
if (circle != null)
{
double centerDistance = Math.Sqrt(Math.Pow(circle.Center.X - Center.X, 2) + Math.Pow(circle.Center.Y - Center.Y, 2));
if (centerDistance <= circle.Radius + Radius)
return true;
}
return false;
}