intersections: move tests from doctest to unit.

This commit is contained in:
Bill Thiede 2021-07-27 21:51:26 -07:00
parent 42e8ebe3bd
commit 5debb16d10

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@ -79,50 +79,6 @@ impl<'i> Intersections<'i> {
self.0.len()
}
/// Finds nearest hit for this collection of intersections.
///
/// # Examples
/// ```
/// use rtchallenge::{
/// intersections::{Intersection, Intersections},
/// rays::Ray,
/// shapes::{intersect, Shape},
/// tuples::Tuple,
/// };
///
/// // The hit, when all intersections have positive t.
/// let s = Shape::sphere();
/// let i1 = Intersection::new(1., &s);
/// let i2 = Intersection::new(2., &s);
/// let xs = Intersections::new(vec![i2, i1.clone()]);
/// let i = xs.hit();
/// assert_eq!(i, Some(&i1));
///
/// // The hit, when some intersections have negative t.
/// let s = Shape::sphere();
/// let i1 = Intersection::new(-1., &s);
/// let i2 = Intersection::new(1., &s);
/// let xs = Intersections::new(vec![i2.clone(), i1]);
/// let i = xs.hit();
/// assert_eq!(i, Some(&i2));
///
/// // The hit, when all intersections have negative t.
/// let s = Shape::sphere();
/// let i1 = Intersection::new(-2., &s);
/// let i2 = Intersection::new(-1., &s);
/// let xs = Intersections::new(vec![i2, i1]);
/// let i = xs.hit();
/// assert_eq!(i, None);
///
/// // The hit is always the lowest nonnegative intersection.
/// let s = Shape::sphere();
/// let i1 = Intersection::new(5., &s);
/// let i2 = Intersection::new(7., &s);
/// let i3 = Intersection::new(-3., &s);
/// let i4 = Intersection::new(2., &s);
/// let xs = Intersections::new(vec![i1, i2, i3, i4.clone()]);
/// let i = xs.hit();
/// assert_eq!(i, Some(&i4));
/// ```
pub fn hit(&self) -> Option<&Intersection> {
self.0.iter().filter(|i| i.t > 0.).min_by(|i1, i2| {
i1.t.partial_cmp(&i2.t)
@ -163,102 +119,6 @@ pub struct PrecomputedData<'i> {
}
/// Precomputes data common to all intersections.
///
/// # Examples
/// ```
/// use rtchallenge::{
/// intersections::{prepare_computations, Intersection, Intersections},
/// rays::Ray,
/// materials::MaterialBuilder,
/// matrices::{Matrix4x4,scaling,translation},
/// shapes::{intersect, Shape,glass_sphere},
/// tuples::{point,vector,Tuple},
/// EPSILON,Float
/// };
///
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
///
/// // Precomputing the state of an intersection.
/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
/// let shape = Shape::sphere();
/// let xs = Intersections::from(Intersection::new(4., &shape));
/// let comps = prepare_computations(&xs[0], &r,&xs);
/// assert_eq!(comps.t, xs[0].t);
/// assert_eq!(comps.object, xs[0].object);
/// assert_eq!(comps.point, Tuple::point(0., 0., -1.));
/// assert_eq!(comps.eyev, Tuple::vector(0., 0., -1.));
/// assert_eq!(comps.normalv, Tuple::vector(0., 0., -1.));
///
/// // The hit, when an intersection occurs on the outside.
/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
/// let shape = Shape::sphere();
/// let xs = Intersections::from(Intersection::new(4., &shape));
/// let comps = prepare_computations(&xs[0], &r,&xs);
/// assert_eq!(comps.inside, false);
///
/// // The hit, when an intersection occurs on the inside.
/// let r = Ray::new(Tuple::point(0., 0., 0.), Tuple::vector(0., 0., 1.));
/// let shape = Shape::sphere();
/// let xs = Intersections::from(Intersection::new(1., &shape));
/// let comps = prepare_computations(&xs[0], &r,&xs);
/// assert_eq!(comps.point, Tuple::point(0., 0., 1.));
/// assert_eq!(comps.eyev, Tuple::vector(0., 0., -1.));
/// assert_eq!(comps.inside, true);
//// // Normal would have been (0, 0, 1), but is inverted when inside.
/// assert_eq!(comps.normalv, Tuple::vector(0., 0., -1.));
///
/// // The hit should offset the point.
/// let r = Ray::new(Tuple::point(0., 0., -5.), Tuple::vector(0., 0., 1.));
/// let mut shape = Shape::sphere();
/// shape .set_transform(Matrix4x4::translation(0.,0.,1.));
/// let xs = Intersections::from(Intersection::new(5., &shape));
/// let comps = prepare_computations(&xs[0], &r,&xs);
/// assert!(comps.over_point.z< -EPSILON/2.);
/// assert!(comps.point.z>comps.over_point.z);
///
/// // Precomputing the reflection vector.
/// let shape = Shape::plane();
/// let r= Ray::new(point(0.,1.,-1.), vector(0.,-(2 as Float).sqrt()/2., (2 as Float).sqrt()/2.));
/// let xs = Intersections::from(Intersection::new((2 as Float).sqrt(), &shape));
/// let comps = prepare_computations(&xs[0], &r,&xs);
/// assert_eq!(comps.reflectv, vector(0.,(2 as Float).sqrt()/2., (2 as Float).sqrt()/2.));
///
/// // Finding n1 and n2 at various intersections.
/// let a = glass_sphere().transform(scaling(2.,2.,2.)).material(MaterialBuilder::default().transparency(1.).refractive_index(1.5).build()?).build()?;
/// let b = glass_sphere().transform(translation(0.,0.,-0.25)).material(MaterialBuilder::default().transparency(1.).refractive_index(2.).build()?).build()?;
/// let c = glass_sphere().transform(translation(0.,0.,0.25)).material(MaterialBuilder::default().transparency(1.).refractive_index(2.5).build()?).build()?;
/// let r = Ray::new(point(0.,0.,-4.), vector(0.,0.,1.));
/// let xs = Intersections::new(vec![
/// Intersection::new(2., &a),
/// Intersection::new(2.75, &b),
/// Intersection::new(3.25, &c),
/// Intersection::new(4.75, &b),
/// Intersection::new(5.25, &c),
/// Intersection::new(6., &a),
/// ]);
/// for (index, n1, n2) in &[
/// (0,1.0,1.5),
/// (1,1.5,2.0),
/// (2,2.0,2.5),
/// (3,2.5,2.5),
/// (4,2.5,1.5),
/// (5,1.5,1.0)]{
/// let comps = prepare_computations(&xs[*index], &r, &xs);
/// assert_eq!(comps.n1, *n1);
/// assert_eq!(comps.n2, *n2);
/// }
///
/// // The under point is offset below the surface.
/// let r = Ray::new(point(0.,0.,-5.), vector(0.,0.,1.));
/// let shape = glass_sphere().transform(translation(0.,0.,1.)).build()?;
/// let xs = Intersections::from(Intersection::new(5.,&shape));
/// let comps = prepare_computations(&xs[0], &r, &xs);
/// assert!(comps.under_point.z > EPSILON/2.);
/// assert!(comps.point.z < comps.under_point.z);
///
/// # Ok(())
/// # }
/// ```
pub fn prepare_computations<'i>(
hit: &'i Intersection,
r: &Ray,
@ -345,83 +205,236 @@ pub fn schlick(comps: &PrecomputedData) -> Float {
#[cfg(test)]
mod tests {
use crate::{
float::consts::SQRT_2,
intersections::{prepare_computations, Intersection, Intersections},
intersections::{prepare_computations, schlick, Intersection, Intersections},
materials::MaterialBuilder,
matrices::translation,
matrices::{scaling, translation},
rays::Ray,
shapes::{glass_sphere, plane, sphere},
shapes::{glass_sphere, Shape},
tuples::{point, vector},
world::World,
Float, EPSILON,
};
use super::schlick;
#[test]
fn schlick_under_total_reflection() -> Result<(), Box<dyn std::error::Error>> {
let shape = glass_sphere().build()?;
let r = Ray::new(point(0., 0., (2 as Float).sqrt() / 2.), vector(0., 1., 0.));
let xs = Intersections::new(vec![
Intersection::new(-(2 as Float).sqrt() / 2., &shape),
Intersection::new((2 as Float).sqrt() / 2., &shape),
]);
let comps = prepare_computations(&xs[1], &r, &xs);
let reflectance = schlick(&comps);
assert_eq!(reflectance, 1.);
Ok(())
mod hit {
use super::*;
#[test]
fn when_all_intersections_have_positive_t() {
let s = Shape::sphere();
let i1 = Intersection::new(1., &s);
let i2 = Intersection::new(2., &s);
let xs = Intersections::new(vec![i2, i1.clone()]);
let i = xs.hit();
assert_eq!(i, Some(&i1));
}
#[test]
fn when_some_intersections_have_negative_t() {
let s = Shape::sphere();
let i1 = Intersection::new(-1., &s);
let i2 = Intersection::new(1., &s);
let xs = Intersections::new(vec![i2.clone(), i1]);
let i = xs.hit();
assert_eq!(i, Some(&i2));
}
#[test]
fn when_all_intersections_have_negative_t() {
let s = Shape::sphere();
let i1 = Intersection::new(-2., &s);
let i2 = Intersection::new(-1., &s);
let xs = Intersections::new(vec![i2, i1]);
let i = xs.hit();
assert_eq!(i, None);
}
#[test]
fn always_the_lowest_nonnegative_intersection() {
let s = Shape::sphere();
let i1 = Intersection::new(5., &s);
let i2 = Intersection::new(7., &s);
let i3 = Intersection::new(-3., &s);
let i4 = Intersection::new(2., &s);
let xs = Intersections::new(vec![i1, i2, i3, i4.clone()]);
let i = xs.hit();
assert_eq!(i, Some(&i4));
}
}
#[test]
fn schlick_perpendicular_viewing_angle() -> Result<(), Box<dyn std::error::Error>> {
let shape = glass_sphere().build()?;
let r = Ray::new(point(0., 0., 0.), vector(0., 1., 0.));
let xs = Intersections::new(vec![
Intersection::new(-1., &shape),
Intersection::new(1., &shape),
]);
let comps = prepare_computations(&xs[1], &r, &xs);
let reflectance = schlick(&comps);
assert!((reflectance - 0.04).abs() < EPSILON);
Ok(())
mod prepare_computations {
use super::*;
#[test]
fn precomputing_the_state_of_intersection() -> Result<(), Box<dyn std::error::Error>> {
let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
let shape = Shape::sphere();
let xs = Intersections::from(Intersection::new(4., &shape));
let comps = prepare_computations(&xs[0], &r, &xs);
assert_eq!(comps.t, xs[0].t);
assert_eq!(comps.object, xs[0].object);
assert_eq!(comps.point, point(0., 0., -1.));
assert_eq!(comps.eyev, vector(0., 0., -1.));
assert_eq!(comps.normalv, vector(0., 0., -1.));
Ok(())
}
#[test]
fn hit_when_intersection_occurs_outside() -> Result<(), Box<dyn std::error::Error>> {
// The hit, when an intersection occurs on the outside.
let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
let shape = Shape::sphere();
let xs = Intersections::from(Intersection::new(4., &shape));
let comps = prepare_computations(&xs[0], &r, &xs);
assert_eq!(comps.inside, false);
Ok(())
}
#[test]
fn hit_when_intersection_occurs_inside() -> Result<(), Box<dyn std::error::Error>> {
// The hit, when an intersection occurs on the inside.
let r = Ray::new(point(0., 0., 0.), vector(0., 0., 1.));
let shape = Shape::sphere();
let xs = Intersections::from(Intersection::new(1., &shape));
let comps = prepare_computations(&xs[0], &r, &xs);
assert_eq!(comps.point, point(0., 0., 1.));
assert_eq!(comps.eyev, vector(0., 0., -1.));
assert_eq!(comps.inside, true);
// Normal would have been (0, 0, 1), but is inverted when inside.
assert_eq!(comps.normalv, vector(0., 0., -1.));
Ok(())
}
#[test]
fn hit_should_offset_the_point() -> Result<(), Box<dyn std::error::Error>> {
// The hit should offset the point.
let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
let mut shape = Shape::sphere();
shape.set_transform(translation(0., 0., 1.));
let xs = Intersections::from(Intersection::new(5., &shape));
let comps = prepare_computations(&xs[0], &r, &xs);
assert!(comps.over_point.z < -EPSILON / 2.);
assert!(comps.point.z > comps.over_point.z);
Ok(())
}
#[test]
fn precomputing_the_reflection_vector() -> Result<(), Box<dyn std::error::Error>> {
// Precomputing the reflection vector.
let shape = Shape::plane();
let r = Ray::new(
point(0., 1., -1.),
vector(0., -(2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.),
);
let xs = Intersections::from(Intersection::new((2 as Float).sqrt(), &shape));
let comps = prepare_computations(&xs[0], &r, &xs);
assert_eq!(
comps.reflectv,
vector(0., (2 as Float).sqrt() / 2., (2 as Float).sqrt() / 2.)
);
Ok(())
}
#[test]
fn finding_n1_and_n2() -> Result<(), Box<dyn std::error::Error>> {
// Finding n1 and n2 at various intersections.
let a = glass_sphere()
.transform(scaling(2., 2., 2.))
.material(
MaterialBuilder::default()
.transparency(1.)
.refractive_index(1.5)
.build()?,
)
.build()?;
let b = glass_sphere()
.transform(translation(0., 0., -0.25))
.material(
MaterialBuilder::default()
.transparency(1.)
.refractive_index(2.)
.build()?,
)
.build()?;
let c = glass_sphere()
.transform(translation(0., 0., 0.25))
.material(
MaterialBuilder::default()
.transparency(1.)
.refractive_index(2.5)
.build()?,
)
.build()?;
let r = Ray::new(point(0., 0., -4.), vector(0., 0., 1.));
let xs = Intersections::new(vec![
Intersection::new(2., &a),
Intersection::new(2.75, &b),
Intersection::new(3.25, &c),
Intersection::new(4.75, &b),
Intersection::new(5.25, &c),
Intersection::new(6., &a),
]);
for (index, n1, n2) in &[
(0, 1.0, 1.5),
(1, 1.5, 2.0),
(2, 2.0, 2.5),
(3, 2.5, 2.5),
(4, 2.5, 1.5),
(5, 1.5, 1.0),
] {
let comps = prepare_computations(&xs[*index], &r, &xs);
assert_eq!(comps.n1, *n1);
assert_eq!(comps.n2, *n2);
}
Ok(())
}
#[test]
fn under_point_offset_below_surface() -> Result<(), Box<dyn std::error::Error>> {
// The under point is offset below the surface.
let r = Ray::new(point(0., 0., -5.), vector(0., 0., 1.));
let shape = glass_sphere().transform(translation(0., 0., 1.)).build()?;
let xs = Intersections::from(Intersection::new(5., &shape));
let comps = prepare_computations(&xs[0], &r, &xs);
assert!(comps.under_point.z > EPSILON / 2.);
assert!(comps.point.z < comps.under_point.z);
Ok(())
}
}
#[test]
fn schlick_small_angle_n2_greater_n1() -> Result<(), Box<dyn std::error::Error>> {
let shape = glass_sphere().build()?;
let r = Ray::new(point(0., 0.99, -2.), vector(0., 0., 1.));
let xs = Intersections::new(vec![Intersection::new(1.8589, &shape)]);
let comps = prepare_computations(&xs[0], &r, &xs);
let reflectance = schlick(&comps);
assert!((reflectance - 0.48873).abs() < EPSILON);
Ok(())
}
#[test]
fn shade_hit_reflective_transparent_material() -> Result<(), Box<dyn std::error::Error>> {
let mut w = World::test_world();
let floor = plane()
.transform(translation(0., -1., 0.))
.material(
MaterialBuilder::default()
.reflective(0.5)
.transparency(0.5)
.refractive_index(1.5)
.build()?,
)
.build()?;
w.objects.push(floor.clone());
let ball = sphere()
.transform(translation(0., -3.5, -0.5))
.material(
MaterialBuilder::default()
.color([1., 0., 0.])
.ambient(0.5)
.build()?,
)
.build()?;
w.objects.push(ball);
let r = Ray::new(point(0., 0., -3.), vector(0., -SQRT_2 / 2., SQRT_2 / 2.));
let xs = Intersections::new(vec![Intersection::new(SQRT_2, &floor)]);
let comps = prepare_computations(&xs[0], &r, &xs);
let color = w.shade_hit(&comps, 5);
assert_eq!(color, [0.93391, 0.69643, 0.69243].into());
Ok(())
mod schlick {
use super::*;
#[test]
fn under_total_reflection() -> Result<(), Box<dyn std::error::Error>> {
let shape = glass_sphere().build()?;
let r = Ray::new(point(0., 0., (2 as Float).sqrt() / 2.), vector(0., 1., 0.));
let xs = Intersections::new(vec![
Intersection::new(-(2 as Float).sqrt() / 2., &shape),
Intersection::new((2 as Float).sqrt() / 2., &shape),
]);
let comps = prepare_computations(&xs[1], &r, &xs);
let reflectance = schlick(&comps);
assert_eq!(reflectance, 1.);
Ok(())
}
#[test]
fn perpendicular_viewing_angle() -> Result<(), Box<dyn std::error::Error>> {
let shape = glass_sphere().build()?;
let r = Ray::new(point(0., 0., 0.), vector(0., 1., 0.));
let xs = Intersections::new(vec![
Intersection::new(-1., &shape),
Intersection::new(1., &shape),
]);
let comps = prepare_computations(&xs[1], &r, &xs);
let reflectance = schlick(&comps);
assert!((reflectance - 0.04).abs() < EPSILON);
Ok(())
}
#[test]
fn small_angle_n2_greater_n1() -> Result<(), Box<dyn std::error::Error>> {
let shape = glass_sphere().build()?;
let r = Ray::new(point(0., 0.99, -2.), vector(0., 0., 1.));
let xs = Intersections::new(vec![Intersection::new(1.8589, &shape)]);
let comps = prepare_computations(&xs[0], &r, &xs);
let reflectance = schlick(&comps);
assert!((reflectance - 0.48873).abs() < EPSILON);
Ok(())
}
}
}