1 files changed, 33 insertions, 0 deletions

diff --git a/Spear/Math/Plane.hs b/Spear/Math/Plane.hs
new file mode 100644
index 0000000..0f5829b
--- /dev/null
+++ b/Spear/Math/Plane.hs
@@ -0,0 +1,33 @@
+module Spear.Math.Plane
+(
+        Plane
+,       plane
+,       classify
+)
+where
+
+
+import Spear.Math.Vector3 as Vector
+
+
+data PointPlanePos = Front | Back | Contained deriving (Eq, Ord, Show)
+
+
+data Plane = Plane {
+        n :: !Vector3,
+        d :: !Float
+} deriving(Eq, Show)
+
+
+-- | Create a plane given a normal vector and a distance from the origin.
+plane :: Vector3 -> Float -> Plane
+plane n d = Plane (normalise n) d
+                
+                
+-- | Classify the given point's relative position with respect to the given plane.
+classify :: Plane -> Vector3 -> PointPlanePos
+classify (Plane n d) pt = case (n `dot` pt - d) `compare` 0 of
+        GT -> Front
+        LT -> Back
+        EQ -> Contained
+        
\ No newline at end of file