private static void TestCase03()
{
// Finding n1 and n2 at various intersections
Shape A = new GlassSphere();
A.Transform = Transformation.Scaling(2, 2, 2);
A.Material.RefractiveIndex = 1.5f;
Shape B = new GlassSphere();
B.Transform = Transformation.Translation(0, 0, -0.25f);
B.Material.RefractiveIndex = 2;
Shape C = new GlassSphere();
C.Transform = Transformation.Translation(0, 0, 0.25f);
C.Material.RefractiveIndex = 2.5f;
Ray r = new Ray(Tuple.Point(0, 0, -4), Tuple.Vector(0, 0, 1));
List <Intersection> xs = Intersection.Aggregate(new Intersection(2, A),
new Intersection(2.75f, B),
new Intersection(3.25f, C),
new Intersection(4.75f, B),
new Intersection(5.25f, C),
new Intersection(6, A));
var expectedN1 = new[] { 1, 1.5f, 2, 2.5f, 2.5f, 1.5f };
var expectedN2 = new[] { 1.5f, 2, 2.5f, 2.5f, 1.5f, 1 };
for (int i = 0; i < 6; ++i)
{
Computation comps = new Computation(xs[i], r, xs);
Assert.Equal(expectedN1[i], comps.N1);
Assert.Equal(expectedN2[i], comps.N2);
}
}
private static void TestCase04()
{
// ShadeHit() with a reflective, transparent material
World w = new DefaultWorld();
Ray r = new Ray(Tuple.Point(0, 0, -3), Tuple.Vector(0, -Sqrt(2) / 2, Sqrt(2) / 2));
Shape floor = new Plane();
floor.Transform = Transformation.Translation(0, -1, 0);
floor.Material.Reflective = 0.5f;
floor.Material.Transparency = 0.5f;
floor.Material.RefractiveIndex = 1.5f;
w.Shapes.Add(floor);
Shape ball = new Sphere();
ball.Material.Color = Tuple.Color(1, 0, 0);
ball.Material.Ambient = 0.5f;
ball.Transform = Transformation.Translation(0, -3.5f, -0.5f);
w.Shapes.Add(ball);
List <Intersection> xs = Intersection.Aggregate(new Intersection(Sqrt(2), floor));
Computation comps = new Computation(xs[0], r, xs);
LightingModel l = new PhongReflection();
Tuple color = l.ShadeHit(w, comps, 5);
Assert.Equal(Tuple.Color(0.93391f, 0.69643f, 0.69243f), color);
}
private static void TestCase11()
{
Sphere s = new Sphere();
Intersection i1 = new Intersection(1, s);
Intersection i2 = new Intersection(2, s);
List <Intersection> xs = Intersection.Aggregate(i2, i1);
Intersection i = Intersection.Hit(xs);
Assert.Equal(i1, i);
i1 = new Intersection(-1, s);
i2 = new Intersection(1, s);
xs = Intersection.Aggregate(i2, i1);
i = Intersection.Hit(xs);
Assert.Equal(i2, i);
i1 = new Intersection(-2, s);
i2 = new Intersection(-1, s);
xs = Intersection.Aggregate(i2, i1);
i = Intersection.Hit(xs);
Assert.Null(i);
i1 = new Intersection(5, s);
i2 = new Intersection(7, s);
Intersection i3 = new Intersection(-3, s);
Intersection i4 = new Intersection(2, s);
xs = Intersection.Aggregate(i1, i2, i3, i4);
i = Intersection.Hit(xs);
Assert.Equal(i4, i);
}
private static void TestCase03()
{
// The Schlick approximation with small angle and n2 > n1
Shape shape = new GlassSphere();
Ray r = new Ray(Tuple.Point(0, 0.99f, -2), Tuple.Vector(0, 0, 1));
List <Intersection> xs = Intersection.Aggregate(new Intersection(1.8589f, shape));
Computation comps = new Computation(xs[0], r, xs);
float reflectance = Fresnel.Schlick(comps);
Assert.Equal(0.48873f, reflectance, 5);
}
private static void TestCase02()
{
// The Schlick approximation with a perpendicular viewing angle
Shape shape = new GlassSphere();
Ray r = new Ray(Tuple.Point(0, 0, 0), Tuple.Vector(0, 1, 0));
List <Intersection> xs = Intersection.Aggregate(new Intersection(-1, shape), new Intersection(1, shape));
Computation comps = new Computation(xs[1], r, xs);
float reflectance = Fresnel.Schlick(comps);
Assert.Equal(0.04f, reflectance, 5);
}
private static void TestCase01()
{
// The Schlick approximation under total internal reflection
Shape shape = new GlassSphere();
Ray r = new Ray(Tuple.Point(0, 0, Sqrt(2) / 2), Tuple.Vector(0, 1, 0));
List <Intersection> xs = Intersection.Aggregate(new Intersection(-Sqrt(2) / 2, shape), new Intersection(Sqrt(2) / 2, shape));
Computation comps = new Computation(xs[1], r, xs);
float reflectance = Fresnel.Schlick(comps);
Assert.Equal(1, reflectance);
}
private static void TestCase09()
{
Sphere s = new Sphere();
Intersection i1 = new Intersection(1, s);
Intersection i2 = new Intersection(2, s);
List <Intersection> xs = Intersection.Aggregate(i1, i2);
Assert.Equal(2, xs.Count);
Assert.Equal(1, xs[0].T);
Assert.Equal(2, xs[1].T);
}
private static void TestCase05()
{
// The refracted color with an opaque surface
World w = new DefaultWorld();
Shape shape = w.Shapes[0];
Ray r = new Ray(Tuple.Point(0, 0, -5), Tuple.Vector(0, 0, 1));
List <Intersection> xs = Intersection.Aggregate(new Intersection(4, shape), new Intersection(6, shape));
Computation comps = new Computation(xs[0], r, xs);
LightingModel l = new PhongReflection();
Tuple c = l.RefractedColor(w, comps, 5);
Assert.Equal(Tuple.Color(0, 0, 0), c);
}
private static void TestCase04()
{
// The under point is offset below the surface
Ray r = new Ray(Tuple.Point(0, 0, -5), Tuple.Vector(0, 0, 1));
Shape shape = new GlassSphere();
shape.Transform = Transformation.Translation(0, 0, 1);
Intersection i = new Intersection(5, shape);
List <Intersection> xs = Intersection.Aggregate(i);
Computation comps = new Computation(i, r, xs);
Assert.True(comps.UnderPoint.Z > Constants.floatEps / 2);
Assert.True(comps.Point.Z < comps.UnderPoint.Z);
}
private static void TestCase07()
{
// The refracted color under total internal reflection
World w = new DefaultWorld();
Shape shape = w.Shapes[0];
shape.Material.Transparency = 1;
shape.Material.RefractiveIndex = 1.5f;
Ray r = new Ray(Tuple.Point(0, 0, Sqrt(2) / 2), Tuple.Vector(0, 1, 0));
List <Intersection> xs = Intersection.Aggregate(new Intersection(-Sqrt(2) / 2, shape), new Intersection(Sqrt(2) / 2, shape));
Computation comps = new Computation(xs[1], r, xs);
LightingModel l = new PhongReflection();
Tuple c = l.RefractedColor(w, comps, 5);
Assert.Equal(Tuple.Color(0, 0, 0), c);
}
private static void TestCase06()
{
// The refracted color at the maximum recursive depth
World w = new DefaultWorld();
Shape shape = w.Shapes[0];
shape.Material.Transparency = 1;
shape.Material.RefractiveIndex = 1.5f;
Ray r = new Ray(Tuple.Point(0, 0, -5), Tuple.Vector(0, 0, 1));
List <Intersection> xs = Intersection.Aggregate(new Intersection(4, shape), new Intersection(6, shape));
Computation comps = new Computation(xs[0], r, xs);
LightingModel l = new PhongReflection();
Tuple c = l.RefractedColor(w, comps, 0);
Assert.Equal(Tuple.Color(0, 0, 0), c);
}
private static void TestCase08()
{
// The refracted color with a refracted ray
World w = new DefaultWorld();
Shape A = w.Shapes[0];
A.Material.Ambient = 1;
A.Material.Pattern = new PositionPattern();
Shape B = w.Shapes[1];
B.Material.Transparency = 1;
B.Material.RefractiveIndex = 1.5f;
Ray r = new Ray(Tuple.Point(0, 0, 0.1f), Tuple.Vector(0, 1, 0));
List <Intersection> xs = Intersection.Aggregate(new Intersection(-0.9899f, A),
new Intersection(-0.4899f, B),
new Intersection(0.4899f, B),
new Intersection(0.9899f, A));
Computation comps = new Computation(xs[2], r, xs);
LightingModel l = new PhongReflection();
Tuple c = l.RefractedColor(w, comps, 5);
Assert.Equal(Tuple.Color(0, 0.99888f, 0.04725f), c);
}
