Add a find_containing_cubes function to the Grid module.

diff --git a/src/Grid.hs b/src/Grid.hs
index e45a0f4380946f281533f27dcc9745ac8f3e4ce9..1a436acdc00d9276ceb1e25b7080355577822bf3 100644 (file)
--- a/src/Grid.hs
+++ b/src/Grid.hs
@@ -6,6 +6,10 @@ where
 
 import Cube (Cube(Cube))
 import FunctionValues
+import Misc (flatten)
+import Point (Point)
+import ThreeDimensional (contains_point)
+
 
 -- | Our problem is defined on a Grid. The grid size is given by the
 --   positive number h. The function values are the values of the
@@ -58,3 +62,13 @@ cube_at g i j k
     | j >= length ((cubes g) !! i) = Nothing
     | k >= length (((cubes g) !! i) !! j) = Nothing
     | otherwise = Just $ (((cubes g) !! i) !! j) !! k
+
+
+-- | Takes a 'Grid', and returns all 'Cube's belonging to it that
+--   contain the given 'Point'.
+find_containing_cubes :: Grid -> Point -> [Cube]
+find_containing_cubes g p =
+    filter contains_our_point all_cubes
+    where
+      all_cubes = flatten $ cubes g
+      contains_our_point = flip contains_point p