5 files changed, 46 insertions, 20 deletions
diff --git a/src/algebra/line.rs b/src/algebra/line.rs
new file mode 100644
index 0000000..45733b9
--- /dev/null
+++ b/src/algebra/line.rs
@@ -0,0 +1,24 @@
+use crate::{particle_system::Scalar, Point, Vector};
+
+pub struct Line {
+    pub point: Point,
+
+    /// Has to be normalized
+    pub vector: Vector,
+}
+
+impl Line {
+    pub fn new(point: Point, vector: Vector) -> Self {
+        Self {
+            point,
+            vector: vector.normalize(),
+        }
+    }
+
+    pub fn distance_to_point(&self, point: Point) -> Scalar {
+        let diff = point - self.point;
+        let lambda = diff.dot(&self.vector);
+
+        (diff - lambda * self.vector).norm()
+    }
+}
diff --git a/src/algebra/mod.rs b/src/algebra/mod.rs
new file mode 100644
index 0000000..884ccfc
--- /dev/null
+++ b/src/algebra/mod.rs
@@ -0,0 +1,2 @@
+pub mod plane;
+pub mod line;
diff --git a/src/algebra/plane.rs b/src/algebra/plane.rs
new file mode 100644
index 0000000..e82c843
--- /dev/null
+++ b/src/algebra/plane.rs
@@ -0,0 +1,6 @@
+use crate::{Point, Vector};
+
+pub struct Plane {
+    point: Point,
+    vectors: [Vector; 2],
+}
diff --git a/src/constraint/slider.rs b/src/constraint/slider.rs
index 526b6f8..ceea4ea 100644
--- a/src/constraint/slider.rs
+++ b/src/constraint/slider.rs
@@ -2,18 +2,18 @@ use std::usize;
 
 use nalgebra::{DVector, RowDVector};
 
-use crate::{particle_system::{Scalar, N}, ParticleSystem, Point, Vector};
+use crate::{
+    algebra::line::Line,
+    particle_system::{Scalar, N},
+    ParticleSystem, Point, Vector,
+};
 
 use super::Constraint;
 
-
 pub struct SliderConstraint {
     pub particle_id: usize,
 
-    pub point: Point,
-
-    /// Has to be normalized
-    pub dir: Vector,
+    pub line: Line,
 
     jacobian: RowDVector<Scalar>,
 }
@@ -21,15 +21,11 @@ pub struct SliderConstraint {
 impl ParticleSystem {
     pub fn add_slider_constraint(&mut self, particle_id: usize, direction: Vector) {
         let point = self.particles[particle_id].position;
-        self.constraints.push(Box::new(
-            SliderConstraint {
-                particle_id,
-                point,
-                dir: direction.normalize(),
-                jacobian: RowDVector::zeros(self.particles.len() * N),
-            }
-        ));
-
+        self.constraints.push(Box::new(SliderConstraint {
+            particle_id,
+            line: Line::new(point, direction),
+            jacobian: RowDVector::zeros(self.particles.len() * N),
+        }));
     }
 }
 
@@ -40,11 +36,8 @@ impl Constraint for SliderConstraint {
 
     fn c(&self, q: &DVector<Scalar>) -> Scalar {
         let position = q.fixed_rows::<N>(self.particle_id * N);
-        let d = position - self.point.coords;
-        let lambda = d.dot(&self.dir);
-        let distance_to_line = d - lambda * self.dir;
-
-        distance_to_line.norm()
+        let point = Point::from_coordinates(position.into());
+        self.line.distance_to_point(point)
     }
 
     fn set_jacobian(&mut self, jacobian: RowDVector<Scalar>) {
diff --git a/src/main.rs b/src/main.rs
index 58e649f..0b5704b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -10,6 +10,7 @@ mod particle_system;
 mod ppm;
 mod solver;
 mod force;
+mod algebra;
 
 fn main() {
     let ppm = PPM {