public void ARayMissesASphere()
{
var r = new Ray(Tuple.Point(0, 2, -5), Tuple.Vector(0, 0, 1));
var s = new Sphere();
var intersections = IntersectionHelpers.Intersections(s, r);
Assert.Empty(intersections);
}
public void ARayIntersectsASphereAtATangent()
{
var r = new Ray(Tuple.Point(0, 1, -5), Tuple.Vector(0, 0, 1));
var s = new Sphere();
var intersections = IntersectionHelpers.Intersections(s, r);
Assert.Equal(2, intersections.Count);
Assert.Equal(5f, intersections[0].T);
Assert.Equal(5f, intersections[1].T);
}
public void ASphereIsBehindARay()
{
var r = new Ray(Tuple.Point(0, 0, 5), Tuple.Vector(0, 0, 1));
var s = new Sphere();
var intersections = IntersectionHelpers.Intersections(s, r);
Assert.Equal(2, intersections.Count);
Assert.Equal(-6f, intersections[0].T);
Assert.Equal(-4f, intersections[1].T);
}
public void ARayOriginatesInsideASphere()
{
var r = new Ray(Tuple.Point(0, 0, 0), Tuple.Vector(0, 0, 1));
var s = new Sphere();
var intersections = IntersectionHelpers.Intersections(s, r);
Assert.Equal(2, intersections.Count);
Assert.Equal(-1f, intersections[0].T);
Assert.Equal(1f, intersections[1].T);
}
public void HitWhenSomeIntersectionsHaveNegativeT()
{
var s = new Sphere();
var i1 = new Intersection(-1, s);
var i2 = new Intersection(1, s);
var xs = IntersectionHelpers.Intersections(i1, i2);
var i = xs.Hit();
Assert.Equal(i2, i);
}
public void HitWhenAllIntersectionsHavePositiveT()
{
var s = new Sphere();
var i1 = new Intersection(1, s);
var i2 = new Intersection(2, s);
var xs = IntersectionHelpers.Intersections(i1, i2);
var i = xs.Hit();
Assert.Equal(i1, i);
}
public void HitWhenAllIntersectionsHaveNegativeT()
{
var s = new Sphere();
var i1 = new Intersection(-2, s);
var i2 = new Intersection(-2, s);
var xs = IntersectionHelpers.Intersections(i1, i2);
var i = xs.Hit();
Assert.Null(i);
}
public void AggregatingIntersections()
{
var s = new Sphere();
var i1 = new Intersection(1, s);
var i2 = new Intersection(2, s);
var xs = IntersectionHelpers.Intersections(i1, i2);
Assert.Equal(2, xs.Count);
Assert.Equal(1, xs[0].T);
Assert.Equal(2, xs[1].T);
}
public void HitIsAlwaysLowestNonNegativeIntersection()
{
var s = new Sphere();
var i1 = new Intersection(5, s);
var i2 = new Intersection(7, s);
var i3 = new Intersection(3, s);
var i4 = new Intersection(2, s);
var xs = IntersectionHelpers.Intersections(i1, i2, i3, i4);
var i = xs.Hit();
Assert.Equal(i4, i);
}
public void ARayIntersectsASphereWithTwoPoints()
{
var r = new Ray(Tuple.Point(0, 0, -5), Tuple.Vector(0, 0, 1));
var s = new Sphere();
var intersections = IntersectionHelpers.Intersections(s, r);
Assert.Equal(2, intersections.Count);
Assert.Equal(4f, intersections[0].T);
Assert.Equal(s, intersections[0].Object);
Assert.Equal(6f, intersections[1].T);
Assert.Equal(s, intersections[1].Object);
}