public void FindingN1AndN2AtVariousIntersections(int index, double n1, double n2)
{
var a = new GlassSphere()
{
Transform = Transform.Scale(2, 2, 2),
};
var b = new GlassSphere()
{
Transform = Transform.Translate(0, 0, -0.25),
};
var c = new GlassSphere()
{
Transform = Transform.Translate(0, 0, 25),
};
a.Material.RefractiveIndex = 1.5;
b.Material.RefractiveIndex = 2.0;
c.Material.RefractiveIndex = 2.5;
var r = new Ray(Vector4.CreatePosition(0, 0, -4), Vector4.CreateDirection(0, 0, 1));
var xs = IntersectionList.Create(
new Intersection(2, a),
new Intersection(2.75, b),
new Intersection(3.25, c),
new Intersection(4.75, b),
new Intersection(5.25, c),
new Intersection(6, a));
var comps = xs[index].Precompute(r, xs);
Assert.Equal(n1, comps.N1);
Assert.Equal(n2, comps.N2);
}
public void HelperForSphereWithGlassyMaterial()
{
var s = new GlassSphere();
Assert.Equal(Matrix4x4.Identity, s.Transform);
Assert.Equal(1.0, s.Material.Transparency);
Assert.Equal(1.5, s.Material.RefractiveIndex);
}
public void SchlickApproxWithSmallAngleAndN2GreaterThanN1()
{
var shape = new GlassSphere();
var r = new Ray(Vector4.CreatePosition(0, 0.99, -2), Vector4.CreateDirection(0, 0, 1));
var xs = IntersectionList.Create(
new Intersection(1.8589, shape));
var comps = xs[0].Precompute(r, xs);
var reflectance = comps.SchlicksApproximation();
const int prec = 5;
Assert.Equal(0.48873, reflectance, prec);
}
public void SchlickApproxWithPerpendicularViewingAngle()
{
var shape = new GlassSphere();
var r = new Ray(Vector4.CreatePosition(0, 0, 0), Vector4.CreateDirection(0, 1, 0));
var xs = IntersectionList.Create(
new Intersection(-1, shape),
new Intersection(1, shape));
var comps = xs[1].Precompute(r, xs);
var reflectance = comps.SchlicksApproximation();
const int prec = 8;
Assert.Equal(0.04, reflectance, prec);
}
public void UnderPointIsOffsetBelowTheSurface()
{
var r = new Ray(Vector4.CreatePosition(0, 0, -5), Vector4.CreateDirection(0, 0, 1));
var shape = new GlassSphere()
{
Transform = Transform.Translate(0, 0, 1),
};
var i = new Intersection(5, shape);
var xs = IntersectionList.Create(i);
var comps = i.Precompute(r, xs);
Assert.True(comps.UnderPoint.Z > Intersection.Epsilon / 2);
Assert.True(comps.Point.Z < comps.UnderPoint.Z);
}
public void SchlickApproxUnderTotalInternalReflection()
{
var shape = new GlassSphere();
var r = new Ray(
Vector4.CreatePosition(0, 0, Math.Sqrt(2)/2),
Vector4.CreateDirection(0, 1, 0));
var xs = IntersectionList.Create(
new Intersection(-Math.Sqrt(2)/2, shape),
new Intersection(Math.Sqrt(2)/2, shape));
var comps = xs[1].Precompute(r, xs);
var reflectance = comps.SchlicksApproximation();
Assert.Equal(1.0, reflectance);
}
