Store the positive offset in planes

csg/src/plane.rs

@@ -1,7 +1,8 @@
-use glam::{Mat3, Vec3};
+use glam::{Mat3, Vec3, Vec4};
 
 use crate::math;
 
+//? Should this be normalised or does that risk introducing fpp errors
 #[derive(Clone, Copy, Debug)]
 pub struct Plane {
     pub normal: Vec3,
@@ -12,9 +13,13 @@ impl Plane {
     pub fn from_point_normal(point: Vec3, normal: Vec3) -> Self {
         Self {
             normal,
-            offset: -point.dot(normal),
+            offset: point.dot(normal),
         }
     }
+
+    pub fn into_vec4(&self) -> Vec4 {
+        glam::vec4(self.normal.x, self.normal.y, self.normal.z, -self.offset)
+    }
 }
 
 pub struct PlaneIntersection {