library: shape: add InterpolatedTriangle type

This is a triangle with added normal interpolation at its edges. This is
particularly useful when rendering mesh objects.
This commit is contained in:
Bruno BELANYI 2020-03-23 16:33:02 +01:00
parent 3b5410aef9
commit 5c0fc9689e
3 changed files with 158 additions and 1 deletions

View file

@ -0,0 +1,153 @@
use super::triangle::Triangle;
use super::Shape;
use crate::{Point, Point2D, Vector};
use beevee::aabb::AABB;
use beevee::ray::Ray;
use nalgebra::Unit;
use serde::Deserialize;
/// Represent a triangle with interpolated normals inside the scene.
#[derive(Clone, Debug, PartialEq, Deserialize)]
pub struct InterpolatedTriangle {
#[serde(flatten)]
tri: Triangle,
// FIXME: serialize with unit
normals: [Unit<Vector>; 3],
}
impl InterpolatedTriangle {
/// Creates a new `InterpolatedTriangle` from 3 [`Point`]s and 3 [`Vector`]s.
///
/// [`Point`]: ../../type.Point.html
/// [`Point`]: ../../type.Vector.html
///
/// # Examples
///
/// ```
/// # use pathtracer::shape::InterpolatedTriangle;
/// # use pathtracer::{Point, Vector};
/// #
/// let t = InterpolatedTriangle::new(
/// Point::new(1.0, 0.0, 0.0),
/// Point::new(0.0, 1.0, 0.0),
/// Point::new(0.0, 0.0, 1.0),
/// Vector::x_axis(),
/// Vector::y_axis(),
/// Vector::z_axis(),
/// );
/// ```
pub fn new(
c0: Point,
c1: Point,
c2: Point,
n0: Unit<Vector>,
n1: Unit<Vector>,
n2: Unit<Vector>,
) -> Self {
InterpolatedTriangle {
tri: Triangle::new(c0, c1, c2),
normals: [n0, n1, n2],
}
}
}
impl Shape for InterpolatedTriangle {
fn intersect(&self, ray: &Ray) -> Option<f32> {
self.tri.intersect(ray)
}
fn normal(&self, point: &Point) -> Unit<Vector> {
let (u, v) = {
let c = self.tri.barycentric(point);
(c.x, c.y)
};
let interpol = self.normals[0].as_ref() * (1. - u - v)
+ self.normals[1].as_ref() * u
+ self.normals[2].as_ref() * v;
Unit::new_normalize(interpol)
}
fn project_texel(&self, point: &Point) -> Point2D {
self.tri.project_texel(point)
}
fn aabb(&self) -> AABB {
self.tri.aabb()
}
fn centroid(&self) -> Point {
self.tri.centroid()
}
}
#[cfg(test)]
mod test {
use super::*;
fn simple_triangle() -> InterpolatedTriangle {
InterpolatedTriangle::new(
Point::origin(),
Point::new(0., 1., 1.),
Point::new(0., 1., 0.),
Vector::x_axis(),
Vector::y_axis(),
Vector::z_axis(),
)
}
#[test]
fn normal_interpolation_at_c0_works() {
let triangle = simple_triangle();
let normal = triangle.normal(&Point::origin());
assert_eq!(normal, Vector::x_axis());
}
#[test]
fn normal_interpolation_at_c1_works() {
let triangle = simple_triangle();
let normal = triangle.normal(&Point::new(0., 1., 1.));
assert_eq!(normal, Vector::y_axis());
}
#[test]
fn normal_interpolation_at_c2_works() {
let triangle = simple_triangle();
let normal = triangle.normal(&Point::new(0., 1., 0.));
assert_eq!(normal, Vector::z_axis());
}
#[test]
fn normal_interpolation_at_center_works() {
let triangle = simple_triangle();
let center = Point::new(0., 2. / 3., 1. / 3.);
let normal = triangle.normal(&center);
let expected = Unit::new_normalize(Vector::new(1., 1., 1.));
assert!((normal.as_ref() - expected.as_ref()).magnitude() < 1e-5)
}
#[test]
fn deserialization_works() {
let yaml = r#"
corners:
- [0.0, 0.0, 0.0]
- [0.0, 1.0, 1.0]
- [0.0, 1.0, 0.0]
normals:
- [1.0, 0.0, 0.0]
- [0.0, 1.0, 0.0]
- [0.0, 0.0, 1.0]
"#;
let triangle: InterpolatedTriangle = serde_yaml::from_str(yaml).unwrap();
assert_eq!(
triangle,
InterpolatedTriangle::new(
Point::origin(),
Point::new(0., 1., 1.),
Point::new(0., 1., 0.),
Vector::x_axis(),
Vector::y_axis(),
Vector::z_axis(),
)
)
}
}

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@ -18,6 +18,7 @@ use serde::Deserialize;
pub enum ShapeEnum {
Sphere,
Triangle,
InterpolatedTriangle,
}
/// Represent an abstract shape inside the scene.
@ -51,6 +52,9 @@ impl Intersected for dyn Shape {
}
}
mod interpolated_triangle;
pub use interpolated_triangle::*;
mod sphere;
pub use sphere::*;

View file

@ -38,7 +38,7 @@ impl Triangle {
}
}
fn barycentric(&self, point: &Point) -> Point2D {
pub(crate) fn barycentric(&self, point: &Point) -> Point2D {
let c0_pos = point - self.c0;
// P - A = u * (B - A) + v * (C - A)
// (C - A) = v0 is c0c2