67 lines
1.7 KiB
Rust
67 lines
1.7 KiB
Rust
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use super::super::core::LinearColor;
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use super::super::{Point, Vector};
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use super::{Light, SpatialLight};
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/// Represent a light emanating from a far away source, with parallel rays on all points.
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#[derive(Debug, PartialEq)]
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pub struct DirectionalLight {
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direction: Vector,
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color: LinearColor,
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}
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impl DirectionalLight {
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pub fn new(direction: Vector, color: LinearColor) -> Self {
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DirectionalLight {
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direction: direction.normalize(),
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color,
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}
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}
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}
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impl Light for DirectionalLight {
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fn illumination(&self, _: &Point) -> LinearColor {
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self.color.clone()
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}
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}
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impl SpatialLight for DirectionalLight {
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fn to_source(&self, _: &Point) -> (Vector, f32) {
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(self.direction * -1., std::f32::INFINITY)
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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 direction = Vector::new(1., 0., 0.);
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let color = LinearColor::new(1., 1., 1.);
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let light = DirectionalLight::new(direction, color.clone());
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let res = DirectionalLight { direction, 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 direction = Vector::new(1., 0., 0.);
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let color = LinearColor::new(1., 1., 1.);
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DirectionalLight::new(direction, 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., 1., 1.));
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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.), std::f32::INFINITY);
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assert_eq!(ans, expected)
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}
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}
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