public void Precomputing_the_reflection_vector()
{
var shape = new Plane();
var ray = new Ray(new Point(0, 1, -1), new Vector(0, -Math.Sqrt(2) / 2, Math.Sqrt(2) / 2));
var hit = new Intersection(Math.Sqrt(2), shape);
var state = IntersectionState.Create(hit, ray, new IntersectionList(hit));
state.Reflection.Should().Be(new Vector(0, Math.Sqrt(2) / 2, Math.Sqrt(2) / 2));
}
public void The_hit_should_be_preserved_when_calculating_the_intersection_state()
{
var hit = new Intersection(1, _triangle, 0.45, 0.25);
var ray = new Ray(new Point(-0.2, 0.3, -2), Vector.UnitZ);
var intersections = new IntersectionList(hit);
var state = IntersectionState.Create(hit, ray, intersections);
state.Normal.Should().Be(new Vector(-0.5547, 0.83205, 0));
}
public void Precomputing_the_hit_when_an_intersection_occurs_on_the_outside()
{
var ray = new Ray(new Point(0, 0, -5), new Vector(0, 0, 1));
var shape = new Sphere();
var hit = new Intersection(4, shape);
var state = IntersectionState.Create(hit, ray, new IntersectionList(hit));
state.IsInside.Should().BeFalse();
}
public void Precomputing_the_hit_should_offset_the_point()
{
var ray = new Ray(new Point(0, 0, -5), Vector.UnitZ);
var shape = new Sphere(transform: Matrix4x4.CreateTranslation(0, 0, 1));
var hit = new Intersection(5, shape);
var state = IntersectionState.Create(hit, ray, new IntersectionList(hit));
state.OverPoint.Z.Should().BeLessThan(-NumberExtensions.Epsilon / 2);
state.Point.Z.Should().BeGreaterThan(state.OverPoint.Z);
}
public void ShadeHit_should_shade_an_intersection()
{
var world = World.CreateDefaultWorld();
var ray = new Ray(new Point(0, 0, -5), Vector.UnitZ);
Shape shape = world.Shapes[0];
var intersection = new Intersection(4, shape);
var state = IntersectionState.Create(intersection, ray, new IntersectionList(intersection));
Color color = world.ShadeHit(state);
color.Should().Be(new Color(0.38066, 0.47583, 0.2855));
}
public void ShadeHit_should_shade_an_intersection_from_the_inside()
{
var world = World.CreateDefaultWorld().ChangeLights(new PointLight(new Point(0, 0.25, 0), Colors.White));
var ray = new Ray(new Point(0, 0, 0), Vector.UnitZ);
Shape shape = world.Shapes[1];
var intersection = new Intersection(0.5, shape);
var state = IntersectionState.Create(intersection, ray, new IntersectionList(intersection));
Color color = world.ShadeHit(state);
color.Should().Be(new Color(0.90498, 0.90498, 0.90498));
}
public void RefractedColor_should_return_the_refracted_color_at_the_maximum_recursive_depth()
{
var world = World.CreateDefaultWorld();
var shape = world.Shapes[0].ChangeMaterial(m => m.WithTransparency(1.0).WithRefractiveIndex(1.5));
var ray = new Ray(new Point(0, 0, -5), Vector.UnitZ);
var intersections = new IntersectionList((4, shape), (6, shape));
var state = IntersectionState.Create(intersections[0], ray, intersections);
Color color = world.RefractedColor(state, 0);
color.Should().Be(Colors.Black);
}
public void RefractedColor_should_return_black_for_the_refracted_color_with_an_opaque_surface()
{
var world = World.CreateDefaultWorld();
var shape = world.Shapes[0];
var ray = new Ray(new Point(0, 0, -5), Vector.UnitZ);
var intersections = new IntersectionList((4, shape), (6, shape));
var state = IntersectionState.Create(intersections[0], ray, intersections);
Color color = world.RefractedColor(state, 5);
color.Should().Be(Colors.Black);
}
public void ReflectedColor_should_return_black_for_the_reflected_color_of_a_non_reflective_surface()
{
var world = World.CreateDefaultWorld();
var ray = new Ray(Point.Zero, Vector.UnitZ);
var shape = world.Shapes[1].ChangeMaterial(m => m.WithAmbient(1));
var intersection = new Intersection(1, shape);
var state = IntersectionState.Create(intersection, ray, new IntersectionList(intersection));
Color color = world.ReflectedColor(state);
color.Should().Be(Colors.Black);
}
public void Precomputing_the_state_of_an_intersection()
{
var ray = new Ray(new Point(0, 0, -5), new Vector(0, 0, 1));
var shape = new Sphere();
var hit = new Intersection(4, shape);
var state = IntersectionState.Create(hit, ray, new IntersectionList(hit));
state.T.Should().Be(hit.T);
state.Shape.Should().Be(hit.Shape);
state.Point.Should().Be(new Point(0, 0, -1));
state.Eye.Should().Be(new Vector(0, 0, -1));
state.Normal.Should().Be(new Vector(0, 0, -1));
}
public void RefractedColor_should_return_the_refracted_color_with_a_refracted_ray()
{
var world = World.CreateDefaultWorld();
var a = world.Shapes[0].ChangeMaterial(m => m.WithAmbient(1).WithPattern(new PatternTests.TestPattern()));
var b = world.Shapes[1].ChangeMaterial(m => m.WithTransparency(1).WithRefractiveIndex(1.5));
var ray = new Ray(new Point(0, 0, 0.1), Vector.UnitY);
var intersections = new IntersectionList((-0.9899, a), (-0.4899, b), (0.4899, b), (0.9899, a));
var state = IntersectionState.Create(intersections[2], ray, intersections);
Color color = world.RefractedColor(state, 5);
color.Should().Be(new Color(0, 0.99887, 0.04722));
}
public void RefractedColor_should_return_black_for_the_refracted_color_under_total_internal_reflection()
{
var world = World.CreateDefaultWorld();
var shape = world.Shapes[0].ChangeMaterial(m => m.WithTransparency(1.0).WithRefractiveIndex(1.5));
var ray = new Ray(new Point(0, 0, Math.Sqrt(2) / 2), Vector.UnitY);
var intersections = new IntersectionList((-Math.Sqrt(2) / 2, shape), (Math.Sqrt(2) / 2, shape));
// Note this time we're inside the sphere, so we need to look at intersections[1], not 0.
var state = IntersectionState.Create(intersections[1], ray, intersections);
Color color = world.RefractedColor(state, 5);
color.Should().Be(Colors.Black);
}
public void Precomputing_the_hit_when_an_intersection_occurs_on_the_inside()
{
var ray = new Ray(new Point(0, 0, 0), new Vector(0, 0, 1));
var shape = new Sphere();
var hit = new Intersection(1, shape);
var state = IntersectionState.Create(hit, ray, new IntersectionList(hit));
state.Point.Should().Be(new Point(0, 0, 1));
state.Eye.Should().Be(new Vector(0, 0, -1));
state.IsInside.Should().BeTrue();
// Normal would have been (0, 0, 1) but is inverted!
state.Normal.Should().Be(new Vector(0, 0, -1));
}
public void ShadeHit_should_calculate_the_reflected_color_for_a_reflective_material()
{
var world = World.CreateDefaultWorld();
var floor = new Plane("Floor", Matrix4x4.CreateTranslation(0, -1, 0), new Material(reflective: 0.5));
world = world.AddShapes(floor);
var ray = new Ray(new Point(0, 0, -3), new Vector(0, -Math.Sqrt(2) / 2, Math.Sqrt(2) / 2));
var intersection = new Intersection(Math.Sqrt(2), floor);
var state = IntersectionState.Create(intersection, ray, new IntersectionList(intersection));
var color = world.ShadeHit(state);
color.Should().Be(new Color(0.87675, 0.92434, 0.82917));
}
public void ReflectedColor_should_only_allow_a_maximum_recursion_depth()
{
var world = World.CreateDefaultWorld();
var floor = new Plane("Floor", Matrix4x4.CreateTranslation(0, -1, 0), new Material(reflective: 0.5));
world = world.AddShapes(floor);
var ray = new Ray(new Point(0, 0, -3), new Vector(0, -Math.Sqrt(2) / 2, Math.Sqrt(2) / 2));
var intersection = new Intersection(Math.Sqrt(2), floor);
var state = IntersectionState.Create(intersection, ray, new IntersectionList(intersection));
Color color = world.ReflectedColor(state, 0);
color.Should().Be(Colors.Black);
}
public void ShadeHit_should_shade_an_intersection_in_shadow()
{
var sphere1 = new Sphere();
var sphere2 = new Sphere(transform: Matrix4x4.CreateTranslation(0, 0, 10));
var world = World.CreateDefaultWorld()
.ChangeLights(new PointLight(new Point(0, 0, -10), Colors.White))
.AddShapes(sphere1, sphere2);
var ray = new Ray(new Point(0, 0, 5), Vector.UnitZ);
var intersection = new Intersection(4, sphere2);
var state = IntersectionState.Create(intersection, ray, new IntersectionList(intersection));
Color color = world.ShadeHit(state);
color.Should().Be(new Color(0.1, 0.1, 0.1));
}
public void ShadeHit_should_calculate_the_shade_color_with_a_reflective_and_transparent_material()
{
var floor = new Plane(
"Floor",
Matrix4x4.CreateTranslation(0, -1, 0),
new Material(reflective: 0.5, transparency: 0.5, refractiveIndex: 1.5));
var ball = new Sphere(
"Ball",
Matrix4x4.CreateTranslation(0, -3.5, -0.5),
new Material(Colors.Red, ambient: 0.5));
var world = World.CreateDefaultWorld().AddShapes(floor, ball);
var ray = new Ray(new Point(0, 0, -3), new Vector(0, -Math.Sqrt(2) / 2, Math.Sqrt(2) / 2));
var intersections = new IntersectionList((Math.Sqrt(2), floor));
var state = IntersectionState.Create(intersections[0], ray, intersections);
Color color = world.ShadeHit(state, 5);
color.Should().Be(new Color(0.93391, 0.69643, 0.69243));
}