public void BasicTest()
{
var p1 = Helper.CreatePoint(0, 2, 0);
var p2 = Helper.CreatePoint(0, 1, 0);
SpotLight spotLight = new SpotLight(p1, Color.White, p2, 1, 1);
var p3 = Helper.CreatePoint(0, 0, 0);
var c = spotLight.GetIntensityAt(p1.X, p1.Y, p1.Z, ref p3);
Check.That(c).IsEqualTo(Color.White);
var p4 = Helper.CreatePoint(-5, 0, 0);
c = spotLight.GetIntensityAt(p1.X, p1.Y, p1.Z, ref p4);
Check.That(c).IsEqualTo(Color.Black);
}