public void NormalAt_should_calculate_the_normal_ona_translated_shape()
{
var shape = new TestShape(Matrix4x4.CreateTranslation(0, 1, 0));
var normal = shape.NormalAt(new Point(0, 1.70711, -0.70711));
normal.Should().Be(new Vector(0, 0.70711, -0.70711));
}
public void NormalAt_should_calculate_the_normal_on_a_transformed_shape()
{
var shape = new TestShape(Matrix4x4.CreateRotationZ(Math.PI / 5).Scale(1, 0.5, 1));
var normal = shape.NormalAt(new Point(0, Math.Sqrt(2) / 2, -Math.Sqrt(2) / 2));
normal.Should().Be(new Vector(0, 0.97014, -0.24254));
}
public void Ctor_should_store_the_transform_and_material()
{
var shape = new TestShape(Matrix4x4.CreateTranslation(2, 3, 4), new Material(Colors.Red));
shape.Transform.Should().Be(Matrix4x4.CreateTranslation(2, 3, 4));
shape.Material.Color.Should().Be(Colors.Red);
}
public void Adding_a_child_to_a_group()
{
var group = new Group();
var shape = new TestShape();
group.AddChild(shape);
group.Children.Should().NotBeEmpty();
group.Children.Should().Contain(shape);
shape.Parent.Should().Be(group);
}
public void Intersect_should_translate_world_coordinates_into_local_coordinates()
{
var ray = new Ray(new Point(0, 0, -5), Vector.UnitZ);
var shape = new TestShape(Matrix4x4.CreateScaling(2, 2, 2));
shape.Intersect(ray);
shape.SavedLocalRay !.Origin.Should().Be(new Point(0, 0, -2.5));
shape.SavedLocalRay !.Direction.Should().Be(new Vector(0, 0, 0.5));
shape = (TestShape)shape.ChangeTransform(Matrix4x4.CreateTranslation(5, 0, 0));
shape.Intersect(ray);
shape.SavedLocalRay !.Origin.Should().Be(new Point(-5, 0, -5));
shape.SavedLocalRay !.Direction.Should().Be(new Vector(0, 0, 1));
}
public void Shape_should_default_to_having_a_null_parent()
{
var shape = new TestShape();
shape.Parent.Should().BeNull();
}
public void Shape_should_have_a_default_material()
{
var shape = new TestShape();
shape.Material.Should().BeEquivalentTo(new Material());
}
public void A_Shape_should_default_to_the_identity_matrix_for_the_transform()
{
var shape = new TestShape();
shape.Transform.Should().Be(Matrix4x4.Identity);
}