feat: Compute multipath in the views and implement thin lenses

README.md

@@ -66,7 +66,7 @@ Cherry might be for you if:
 
 ### Now
 - [ ] Systems with beam splitters
-- [ ] Paraxial surface types
+- [X] Thin lens surface types
 - [ ] Surface coatings
 - [ ] Encode designs into URLs and enable sharing via tiny URLs
 

crates/cherry-rs/src/core/math/vec3.rs

@@ -200,6 +200,11 @@ impl Vec3 {
         vecs
     }
 
+    /// Returns `true` if all three components are finite (not infinite or NaN).
+    pub fn is_finite(&self) -> bool {
+        self.e[0].is_finite() && self.e[1].is_finite() && self.e[2].is_finite()
+    }
+
     pub fn approx_eq(&self, rhs: &Self, tol: Float) -> bool {
         (self.e[0] - rhs.e[0]).abs() < tol
             && (self.e[1] - rhs.e[1]).abs() < tol

crates/cherry-rs/src/core/ray.rs

@@ -1,7 +1,9 @@
 #[cfg(feature = "serde")]
 use serde::Serialize;
 
-use crate::core::{Float, PI, math::vec3::Vec3, sequential_model::placement::Placement};
+use crate::core::{
+    Float, PI, math::vec3::Vec3, sequential_model::surface_placement::SurfacePlacement,
+};
 
 /// A single ray to be traced through an optical system.
 ///
@@ -45,14 +47,14 @@ impl Ray {
 
     /// Transform a ray into the local coordinate system of a surface from the
     /// global system.
-    pub fn transform(&mut self, placement: &Placement) {
+    pub fn transform(&mut self, placement: &SurfacePlacement) {
         self.pos = placement.rotation_matrix * (self.pos - placement.position);
         self.dir = placement.rotation_matrix * self.dir;
     }
 
     /// Transform a ray from the local coordinate system of a surface into the
     /// global system.
-    pub fn i_transform(&mut self, placement: &Placement) {
+    pub fn i_transform(&mut self, placement: &SurfacePlacement) {
         self.pos = (placement.inv_rotation_matrix * self.pos) + placement.position;
         self.dir = placement.inv_rotation_matrix * self.dir;
     }