74 lines
2.6 KiB
Rust
74 lines
2.6 KiB
Rust
extern crate nalgebra as na;
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use alga::linear::FiniteDimInnerSpace;
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use na::allocator::Allocator;
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use na::dimension::Dim;
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use na::{DefaultAllocator, RealField, Unit, Vector2, Vector3, VectorN};
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/// Reflects a vector wrt. the hyperplane with normal `plane_normal`.
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fn reflect_wrt_hyperplane_with_algebraic_genericity<V>(plane_normal: &Unit<V>, vector: &V) -> V
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where V: FiniteDimInnerSpace + Copy {
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let n = plane_normal.as_ref(); // Get the underlying vector of type `V`.
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*vector - *n * (n.dot(vector) * na::convert(2.0))
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}
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/// Reflects a vector wrt. the hyperplane with normal `plane_normal`.
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fn reflect_wrt_hyperplane_with_dimensional_genericity<N: RealField, D: Dim>(
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plane_normal: &Unit<VectorN<N, D>>,
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vector: &VectorN<N, D>,
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) -> VectorN<N, D>
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where
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N: RealField,
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D: Dim,
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DefaultAllocator: Allocator<N, D>,
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{
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let n = plane_normal.as_ref(); // Get the underlying V.
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vector - n * (n.dot(vector) * na::convert(2.0))
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}
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/// Reflects a 2D vector wrt. the 2D line with normal `plane_normal`.
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fn reflect_wrt_hyperplane2<N>(plane_normal: &Unit<Vector2<N>>, vector: &Vector2<N>) -> Vector2<N>
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where N: RealField {
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let n = plane_normal.as_ref(); // Get the underlying Vector2
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vector - n * (n.dot(vector) * na::convert(2.0))
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}
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/// Reflects a 3D vector wrt. the 3D plane with normal `plane_normal`.
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/// /!\ This is an exact replicate of `reflect_wrt_hyperplane2, but for 3D.
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fn reflect_wrt_hyperplane3<N>(plane_normal: &Unit<Vector3<N>>, vector: &Vector3<N>) -> Vector3<N>
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where N: RealField {
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let n = plane_normal.as_ref(); // Get the underlying Vector3
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vector - n * (n.dot(vector) * na::convert(2.0))
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}
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fn main() {
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let plane2 = Vector2::y_axis(); // 2D plane normal.
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let plane3 = Vector3::y_axis(); // 3D plane normal.
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let v2 = Vector2::new(1.0, 2.0); // 2D vector to be reflected.
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let v3 = Vector3::new(1.0, 2.0, 3.0); // 3D vector to be reflected.
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// We can call the same function for 2D and 3D.
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assert_eq!(
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reflect_wrt_hyperplane_with_algebraic_genericity(&plane2, &v2).y,
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-2.0
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);
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assert_eq!(
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reflect_wrt_hyperplane_with_algebraic_genericity(&plane3, &v3).y,
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-2.0
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);
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assert_eq!(
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reflect_wrt_hyperplane_with_dimensional_genericity(&plane2, &v2).y,
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-2.0
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);
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assert_eq!(
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reflect_wrt_hyperplane_with_dimensional_genericity(&plane3, &v3).y,
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-2.0
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);
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// Call each specific implementation depending on the dimension.
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assert_eq!(reflect_wrt_hyperplane2(&plane2, &v2).y, -2.0);
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assert_eq!(reflect_wrt_hyperplane3(&plane3, &v3).y, -2.0);
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}
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