public void FiltersIntersections()
{
var s1 = new Sphere();
var s2 = new Cube();
var xs = Intersections.Create(new Intersection(1, s1),
new Intersection(2, s2),
new Intersection(3, s1),
new Intersection(4, s2));
var c = new ConstructiveSolid(ConstructiveOp.Union, s1, s2);
var result = c.FilterIntersections(xs);
result.Count.Should().Be(2);
result[0].Should().Be(xs[0]);
result[1].Should().Be(xs[3]);
c = new ConstructiveSolid(ConstructiveOp.Intersection, s1, s2);
result = c.FilterIntersections(xs);
result.Count.Should().Be(2);
result[0].Should().Be(xs[1]);
result[1].Should().Be(xs[2]);
c = new ConstructiveSolid(ConstructiveOp.Difference, s1, s2);
result = c.FilterIntersections(xs);
result.Count.Should().Be(2);
result[0].Should().Be(xs[0]);
result[1].Should().Be(xs[1]);
}
public void ReflectanceIsSignificantAtSmallViewAngles()
{
var s = Spheres.GlassSphere();
var r = new Ray(new Point(0, 0.99f, -2f), new Vector(0, 0, 1));
var xs = Intersections.Create(new Intersection(1.8589f, s));
var comps = new IntersectionInfo(xs[0], r, xs);
var reflectance = PhongShading.Schlick(comps);
reflectance.Should().BeApproximately(0.48873f, 0.0001f);
}
public void RefractedColorOfOpaqueSurfaceIsBlack()
{
var w = World.Default();
var s = w.Objects[0];
var r = new Ray(new Point(0, 0, -5), new Vector(0, 0, 1));
var xs = Intersections.Create(new Intersection(4f, s), new Intersection(6f, s));
var comps = new IntersectionInfo(xs[0], r, xs);
PhongShading.RefractedColor(w, comps, 5).Should().Be(Colors.Black);
}
public void InterpolatesNormalsForIntersections()
{
var tri = DefaultTriangle();
var i = new Intersection(1, tri, 0.45f, 0.25f);
var r = new Ray(new Point(-0.2f, 0.3f, -2), new Vector(0, 0, 1));
var xs = Intersections.Create(i);
var comps = new IntersectionInfo(i, r, xs);
comps.Normal.Should().Be(new Normal(-0.5547f, 0.83205f, 0));
}
public void HitNoneOnAllNegativeIntersections()
{
var s = new Sphere();
var i1 = new Intersection(-2f, s);
var i2 = new Intersection(-1f, s);
var xs = Intersections.Create(i1, i2);
var hit = xs.Hit();
hit.HasValue.Should().BeFalse();
}
public void HitOnlyPositiveIntersection()
{
var s = new Sphere();
var i1 = new Intersection(-1f, s);
var i2 = new Intersection(1f, s);
var xs = Intersections.Create(i1, i2);
var hit = xs.Hit();
hit?.Should().Be(i2);
}
public void ReflectanceIsSmallAtPerpendicularViewAngles()
{
var s = Spheres.GlassSphere();
var r = new Ray(new Point(0, 0, 0), new Vector(0, 1, 0));
var xs = Intersections.Create(new Intersection(-1f, s),
new Intersection(1f, s));
var comps = new IntersectionInfo(xs[1], r, xs);
var reflectance = PhongShading.Schlick(comps);
reflectance.Should().BeApproximately(0.04f, 0.0001f);
}
public void SchlickApproximationForTotalInternalReflectionIsOne()
{
var s = Spheres.GlassSphere();
var r = new Ray(new Point(0, 0, MathF.Sqrt(2f) / 2f), new Vector(0, 1, 0));
var xs = Intersections.Create(new Intersection(-MathF.Sqrt(2f) / 2f, s),
new Intersection(MathF.Sqrt(2f) / 2f, s));
var comps = new IntersectionInfo(xs[1], r, xs);
var reflectance = PhongShading.Schlick(comps);
reflectance.Should().Be(1f);
}
public void SortsIntersectionsByT()
{
var s = new Sphere();
var i1 = new Intersection(5f, s);
var i2 = new Intersection(7f, s);
var i3 = new Intersection(-3f, s);
var i4 = new Intersection(2f, s);
var xs = Intersections.Create(i1, i2, i3, i4);
var hit = xs.Hit();
hit?.Should().Be(i4);
}
public void RefractedColorIsBlackIfRemainingBouncesIsZero()
{
var w = World.Default();
var s = w.Objects[0];
s.Material.Transparency = 1.0f;
s.Material.RefractiveIndex = 1.5f;
var r = new Ray(new Point(0, 0, -5), new Vector(0, 0, 1));
var xs = Intersections.Create(new Intersection(4f, s), new Intersection(6f, s));
var comps = new IntersectionInfo(xs[0], r, xs);
PhongShading.RefractedColor(w, comps, 0).Should().Be(Colors.Black);
}
public void RefractedColorIsBlackForTotalInternalRefraction()
{
var w = World.Default();
var s = w.Objects[0];
s.Material.Transparency = 1.0f;
s.Material.RefractiveIndex = 1.5f;
var r = new Ray(new Point(0, 0, MathF.Sqrt(2f) / 2f), new Vector(0, 1, 0));
var xs = Intersections.Create(
new Intersection(-MathF.Sqrt(2f) / 2f, s),
new Intersection(MathF.Sqrt(2f) / 2f, s));
// Inside sphere so look at second intersection.
var comps = new IntersectionInfo(xs[1], r, xs);
PhongShading.RefractedColor(w, comps, 5).Should().Be(Colors.Black);
}
public void DeterminesN1AndN2()
{
var a = Spheres.GlassSphere();
a.SetTransform(Transform.Scale(2f));
a.Material.RefractiveIndex = 1.5f;
var b = Spheres.GlassSphere();
b.SetTransform(Transform.TranslateZ(-0.25f));
b.Material.RefractiveIndex = 2.0f;
var c = Spheres.GlassSphere();
c.SetTransform(Transform.TranslateZ(0.25f));
c.Material.RefractiveIndex = 2.5f;
var r = new Ray(new Point(0, 0, -4), new Vector(0, 0, 1));
var xs = Intersections.Create(
new Intersection(2.00f, a),
new Intersection(2.75f, b),
new Intersection(3.25f, c),
new Intersection(4.75f, b),
new Intersection(5.25f, c),
new Intersection(6.00f, a)
);
var comps = new List <IntersectionInfo>();
for (var i = 0; i < xs.Count; i++)
{
comps.Add(new IntersectionInfo(xs[i], r, xs));
}
comps[0].N1.Should().Be(1.0f);
comps[0].N2.Should().Be(1.5f);
comps[1].N1.Should().Be(1.5f);
comps[1].N2.Should().Be(2.0f);
comps[2].N1.Should().Be(2.0f);
comps[2].N2.Should().Be(2.5f);
comps[3].N1.Should().Be(2.5f);
comps[3].N2.Should().Be(2.5f);
comps[4].N1.Should().Be(2.5f);
comps[4].N2.Should().Be(1.5f);
comps[5].N1.Should().Be(1.5f);
comps[5].N2.Should().Be(1.0f);
}
public void HitColorIncludesFresnelEffectOnReflectiveTransparentSurface()
{
var w = World.Default();
var floor = new Plane {
Material = { Transparency = 0.5f, Reflective = 0.5f, RefractiveIndex = 1.5f }
};
floor.SetTransform(Transform.Translate(0, -1, 0));
w.AddObject(floor);
var ball = new Sphere {
Material = { Texture = new SolidColor(new Color(1, 0, 0)), Ambient = 0.5f }
};
ball.SetTransform(Transform.Translate(0, -3.5f, -0.5f));
w.AddObject(ball);
var r = new Ray(new Point(0, 0, -3), new Vector(0, -MathF.Sqrt(2f) / 2f, MathF.Sqrt(2f) / 2f));
var i = new Intersection(MathF.Sqrt(2f), floor);
var xs = Intersections.Create(i);
var comps = new IntersectionInfo(xs[0], r, xs);
PhongShading.HitColor(w, comps, 5).Should().Be(new Color(0.93391f, 0.69643f, 0.69243f));
}
public void RefractsRayWhenHitsTransparentSurface()
{
var w = World.Default();
var a = w.Objects[0];
a.Material.Ambient = 1.0f;
a.Material.Texture = new TestTexture();
var b = w.Objects[1];
b.Material.Transparency = 1.0f;
b.Material.RefractiveIndex = 1.5f;
var r = new Ray(new Point(0, 0, 0.1f), new Vector(0, 1, 0));
var xs = Intersections.Create(
new Intersection(-0.9899f, a),
new Intersection(-0.4899f, b),
new Intersection(0.4899f, b),
new Intersection(0.9899f, a));
var comps = new IntersectionInfo(xs[2], r, xs);
var c = PhongShading.RefractedColor(w, comps, 5);
c.Red.Should().BeApproximately(0f, 0.001f);
c.Green.Should().BeApproximately(0.99888f, 0.001f);
c.Blue.Should().BeApproximately(0.04725f, 0.001f);
}
public IntersectionInfo(Intersection intersection, Ray ray) : this(
intersection, ray, Intersections.Create(intersection))
{
}