public void ShadeHit_ShouldShadeAnIntersection_WhenTheIntersectionPointIsInShadow()
{
// arrange
var sut = new World
{
Lights = ImmutableArray.Create(new PointLight(new(0f, 0f, -10f), Color.White)),
Shapes = ImmutableArray.Create <Shape>(
new Sphere(),
new Sphere {
Transform = Matrix4.Translation(0f, 0f, 10f)
}
)
};
var computations = new IntersectionComputations(
new Ray(new Point(0f, 0f, 5f), Vector.UnitZ),
new Intersection(sut.Shapes[1], 4f)
);
// act
var result = sut.ShadeHit(computations);
// assert
result.Should().Be(new Color(0.1f, 0.1f, 0.1f));
}
}
public void Constructor_ShouldPreComputeIntersectionState_WhenIntersectionIsOnTheOutside()
{
// arrange
var ray = new Ray(new(0f, 0f, -5f), Vector.UnitZ);
var intersection = new Intersection(new Sphere(), 4f);
// act
var result = new IntersectionComputations(ray, intersection);
// assert
using var _ = new AssertionScope();
result.Shape.Should().BeSameAs(intersection.Shape);
result.Time.Should().Be(intersection.Time);
result.Point.Should().Be(new Point(0f, 0f, -1f));
result.Eye.Should().Be(new Vector(0f, 0f, -1f));
result.Normal.Should().Be(new Vector(0f, 0f, -1f));
result.HitInside.Should().BeFalse();
}
public void Constructor_ShouldOffsetOverPointUsingTheSurfaceNormal()
{
// arrange
var ray = new Ray(new(0f, 0f, -5f), Vector.UnitZ);
var intersection = new Intersection(
new Sphere {
Transform = Matrix4.Translation(0f, 0f, 1f)
},
5f
);
// act
var result = new IntersectionComputations(ray, intersection);
// assert
using var _ = new AssertionScope();
result.OverPoint.Z.Should().BeLessThan(-FloatExtensions.ComparisonEpsilon / 2f);
result.Point.Z.Should().BeGreaterThan(result.OverPoint.Z);
}
public void ShadeHit_ShouldShadeAnIntersection_WhenTheIntersectionIsInsideTheShape()
{
// arrange
var sut = World.Default with
{
Lights = ImmutableArray.Create(new PointLight(new(0f, 0.25f, 0f), Color.White))
};
var computations = new IntersectionComputations(
new Ray(Point.Origin, Vector.UnitZ),
new Intersection(sut.Shapes[1], 0.5f)
);
// act
var result = sut.ShadeHit(computations);
// assert
using var _ = new AssertionScope();
result.R.Should().BeApproximately(0.90498f, 1e-5f);
result.G.Should().BeApproximately(0.90498f, 1e-5f);
result.B.Should().BeApproximately(0.90498f, 1e-5f);
}
