Replace Vec references with slices in a few places.

src/mesh.rs

@@ -14,8 +14,8 @@ mod wavefront_obj {
 
     fn get_vertex_and_normal<T: Real>(
         index_tuple: &IndexTuple,
-        vertex_positions: &Vec<[f32; 3]>,
-        normal_positions: &Vec<[f32; 3]>,
+        vertex_positions: &[[f32; 3]],
+        normal_positions: &[[f32; 3]],
     ) -> (Point3<T>, Vector3<T>)
     where
         T: SupersetOf<f32>,
@@ -31,8 +31,8 @@ mod wavefront_obj {
 
     fn get_triangles<T: Real>(
         polygon: &SimplePolygon,
-        vertex_positions: &Vec<[f32; 3]>,
-        normal_positions: &Vec<[f32; 3]>,
+        vertex_positions: &[[f32; 3]],
+        normal_positions: &[[f32; 3]],
         material: Arc<dyn Material<T>>,
     ) -> Vec<Triangle<T>>
     where

src/raycasting/triangle.rs

@@ -139,7 +139,7 @@ fn signed_edge_function<T: Real>(a: &Vector3<T>, b: &Vector3<T>) -> T {
     a.x * b.y - b.x * a.y
 }
 
-fn signed_edge_functions<T: Real>(vertices: &Vec<Vector3<T>>) -> Vector3<T> {
+fn signed_edge_functions<T: Real>(vertices: &[Vector3<T>]) -> Vector3<T> {
     // Iterate over the inputs in such a way that each output element is calculated
     // from the twoother elements of the input. ( (y,z) -> x, (z,x) -> y, (x,y) -> z )
     Vector3::from_iterator(