92 lines
2.4 KiB
Rust
92 lines
2.4 KiB
Rust
use super::{Light, SpatialLight};
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use crate::core::LinearColor;
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use crate::{Point, Vector};
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use serde::Deserialize;
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/// Represent a light emanating from a point in space, following the square distance law.
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#[derive(Debug, PartialEq, Deserialize)]
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pub struct PointLight {
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position: Point,
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color: LinearColor,
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}
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impl PointLight {
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/// Creates a new `PointLight`.
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///
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/// # Examples
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///
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/// ```
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/// # use pathtracer::light::PointLight;
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/// # use pathtracer::core::color::LinearColor;
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/// # use pathtracer::Point;
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/// #
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/// let dir_light = PointLight::new(
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/// Point::origin(),
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/// LinearColor::new(1.0, 0.0, 1.0),
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/// );
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/// ```
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pub fn new(position: Point, color: LinearColor) -> Self {
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PointLight { position, color }
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}
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}
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impl Light for PointLight {
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fn illumination(&self, point: &Point) -> LinearColor {
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let dist = (self.position - point).norm();
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self.color.clone() / dist
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}
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}
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impl SpatialLight for PointLight {
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fn to_source(&self, point: &Point) -> (Vector, f32) {
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let delt = self.position - point;
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let dist = delt.norm();
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(delt.normalize(), dist)
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn new_works() {
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let position = Point::origin();
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let color = LinearColor::black();
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let light = PointLight::new(position, color.clone());
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let res = PointLight { position, color };
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assert_eq!(light, res)
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}
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fn simple_light() -> impl SpatialLight {
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let position = Point::origin();
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let color = LinearColor::new(1., 1., 1.);
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PointLight::new(position, color)
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}
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#[test]
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fn illumination_is_correct() {
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let light = simple_light();
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let lum = light.illumination(&Point::new(1., 0., 0.));
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assert_eq!(lum, LinearColor::new(1., 1., 1.))
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}
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#[test]
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fn to_source_is_correct() {
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let light = simple_light();
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let ans = light.to_source(&Point::new(1., 0., 0.));
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let expected = (Vector::new(-1., 0., 0.), 1.);
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assert_eq!(ans, expected);
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}
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#[test]
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fn deserialization_works() {
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let yaml = "{position: [1.0, 1.0, 1.0], color: {r: 1.0, g: 0.5, b: 0.2}}";
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let light: PointLight = serde_yaml::from_str(yaml).unwrap();
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assert_eq!(
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light,
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PointLight::new(Point::new(1., 1., 1.), LinearColor::new(1., 0.5, 0.2))
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)
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}
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}
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