X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FCube.hs;h=1e83a3e690d4a6b0f39cdc0b0025526650aa81db;hb=2da1ed2fd5929baa129812632068540a3c38a253;hp=2878eb06b76ffb54c0685de2543457faf3d8db29;hpb=f6d0c289ad3397cf392976c24f3afdb17da5d377;p=spline3.git

diff --git a/src/Cube.hs b/src/Cube.hs
index 2878eb0..1e83a3e 100644
--- a/src/Cube.hs
+++ b/src/Cube.hs
@@ -1,8 +1,9 @@
 module Cube
 where
 
+import Data.List ( (\\) )
 import Test.QuickCheck (Arbitrary(..), Gen, Positive(..), choose)
-    
+
 import Cardinal
 import qualified Face (Face(Face, v0, v1, v2, v3))
 import FunctionValues
@@ -103,7 +104,7 @@ zmax c = (2*k' + 1)*delta / 2
 
 instance ThreeDimensional Cube where
     -- | The center of Cube_ijk coincides with v_ijk at
-    --   (ih, jh, kh). See Sorokina and Zeilfelder, p. 76.    
+    --   (ih, jh, kh). See Sorokina and Zeilfelder, p. 76.
     center c = (x, y, z)
            where
              delta = h c
@@ -116,13 +117,13 @@ instance ThreeDimensional Cube where
 
     -- | It's easy to tell if a point is within a cube; just make sure
     --   that it falls on the proper side of each of the cube's faces.
-    contains_point c p
-        | (x_coord p) < (xmin c) = False
-        | (x_coord p) > (xmax c) = False
-        | (y_coord p) < (ymin c) = False
-        | (y_coord p) > (ymax c) = False
-        | (z_coord p) < (zmin c) = False
-        | (z_coord p) > (zmax c) = False
+    contains_point c (x, y, z)
+        | x < (xmin c) = False
+        | x > (xmax c) = False
+        | y < (ymin c) = False
+        | y > (ymax c) = False
+        | z < (zmin c) = False
+        | z > (zmax c) = False
         | otherwise = True
 
 
@@ -198,106 +199,120 @@ right_face c = Face.Face v0' v1' v2' v3'
 
 tetrahedron0 :: Cube -> Tetrahedron
 tetrahedron0 c =
-    Tetrahedron (Cube.fv c) v0' v1' v2' v3'
+    Tetrahedron (Cube.fv c) v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (front_face c)
       v2' = Face.v0 (front_face c)
       v3' = Face.v1 (front_face c)
+      vol = 0
 
 tetrahedron1 :: Cube -> Tetrahedron
 tetrahedron1 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (front_face c)
       v2' = Face.v1 (front_face c)
       v3' = Face.v2 (front_face c)
       fv' = rotate ccwx (Cube.fv c)
+      vol = 0
 
 tetrahedron2 :: Cube -> Tetrahedron
 tetrahedron2 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (front_face c)
       v2' = Face.v2 (front_face c)
       v3' = Face.v3 (front_face c)
       fv' = rotate ccwx $ rotate ccwx $ Cube.fv c
+      vol = 0
 
 tetrahedron3 :: Cube -> Tetrahedron
 tetrahedron3 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (front_face c)
       v2' = Face.v3 (front_face c)
       v3' = Face.v0 (front_face c)
       fv' = rotate cwx (Cube.fv c)
+      vol = 0
 
 tetrahedron4 :: Cube -> Tetrahedron
 tetrahedron4 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (top_face c)
       v2' = Face.v0 (top_face c)
       v3' = Face.v1 (top_face c)
       fv' = rotate cwy (Cube.fv c)
+      vol = 0
 
 tetrahedron5 :: Cube -> Tetrahedron
 tetrahedron5 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (top_face c)
       v2' = Face.v1 (top_face c)
       v3' = Face.v2 (top_face c)
       fv' = rotate cwy $ rotate cwz $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 tetrahedron6 :: Cube -> Tetrahedron
 tetrahedron6 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (top_face c)
       v2' = Face.v2 (top_face c)
       v3' = Face.v3 (top_face c)
-      fv' = rotate cwy $ rotate cwz $ rotate cwz $ Tetrahedron.fv (tetrahedron0 c)
+      fv' = rotate cwy $ rotate cwz
+                       $ rotate cwz
+                       $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 tetrahedron7 :: Cube -> Tetrahedron
 tetrahedron7 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (top_face c)
       v2' = Face.v3 (top_face c)
       v3' = Face.v0 (top_face c)
       fv' = rotate cwy $ rotate ccwz $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 tetrahedron8 :: Cube -> Tetrahedron
 tetrahedron8 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (back_face c)
       v2' = Face.v0 (back_face c)
       v3' = Face.v1 (back_face c)
-      fv' = rotate cwy $ rotate cwy $ (Tetrahedron.fv (tetrahedron0 c))
+      fv' = rotate cwy $ rotate cwy $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 tetrahedron9 :: Cube -> Tetrahedron
 tetrahedron9 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (back_face c)
       v2' = Face.v1 (back_face c)
       v3' = Face.v2 (back_face c)
-      fv' = rotate cwy $ rotate cwy $ rotate cwx $ Tetrahedron.fv (tetrahedron0 c)
+      fv' = rotate cwy $ rotate cwy
+                       $ rotate cwx
+                       $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 tetrahedron10 :: Cube -> Tetrahedron
 tetrahedron10 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (back_face c)
@@ -308,10 +323,11 @@ tetrahedron10 c =
                        $ rotate cwx
                        $ Tetrahedron.fv (tetrahedron0 c)
 
+      vol = 0
 
 tetrahedron11 :: Cube -> Tetrahedron
 tetrahedron11 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (back_face c)
@@ -320,33 +336,36 @@ tetrahedron11 c =
       fv' = rotate cwy $ rotate cwy
                        $ rotate ccwx
                        $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron12 :: Cube -> Tetrahedron
 tetrahedron12 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (down_face c)
       v2' = Face.v0 (down_face c)
       v3' = Face.v1 (down_face c)
       fv' = rotate ccwy (Tetrahedron.fv (tetrahedron0 c))
+      vol = 0
 
 
 tetrahedron13 :: Cube -> Tetrahedron
 tetrahedron13 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (down_face c)
       v2' = Face.v1 (down_face c)
       v3' = Face.v2 (down_face c)
       fv' = rotate ccwy $ rotate ccwz $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron14 :: Cube -> Tetrahedron
 tetrahedron14 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (down_face c)
@@ -355,44 +374,48 @@ tetrahedron14 c =
       fv' = rotate ccwy $ rotate ccwz
                         $ rotate ccwz
                         $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron15 :: Cube -> Tetrahedron
 tetrahedron15 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (down_face c)
       v2' = Face.v3 (down_face c)
       v3' = Face.v0 (down_face c)
       fv' = rotate ccwy $ rotate cwz $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron16 :: Cube -> Tetrahedron
 tetrahedron16 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (right_face c)
       v2' = Face.v0 (right_face c)
       v3' = Face.v1 (right_face c)
       fv' = rotate ccwz (Tetrahedron.fv (tetrahedron0 c))
+      vol = 0
 
 
 tetrahedron17 :: Cube -> Tetrahedron
 tetrahedron17 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (right_face c)
       v2' = Face.v1 (right_face c)
       v3' = Face.v2 (right_face c)
       fv' = rotate ccwz $ rotate cwy $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron18 :: Cube -> Tetrahedron
 tetrahedron18 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (right_face c)
@@ -401,11 +424,12 @@ tetrahedron18 c =
       fv' = rotate ccwz $ rotate cwy
                         $ rotate cwy
                         $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron19 :: Cube -> Tetrahedron
 tetrahedron19 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (right_face c)
@@ -413,33 +437,36 @@ tetrahedron19 c =
       v3' = Face.v0 (right_face c)
       fv' = rotate ccwz $ rotate ccwy
                         $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron20 :: Cube -> Tetrahedron
 tetrahedron20 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (left_face c)
       v2' = Face.v0 (left_face c)
       v3' = Face.v1 (left_face c)
       fv' = rotate cwz (Tetrahedron.fv (tetrahedron0 c))
+      vol = 0
 
 
 tetrahedron21 :: Cube -> Tetrahedron
 tetrahedron21 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (left_face c)
       v2' = Face.v1 (left_face c)
       v3' = Face.v2 (left_face c)
       fv' = rotate cwz $ rotate ccwy $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron22 :: Cube -> Tetrahedron
 tetrahedron22 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (left_face c)
@@ -448,11 +475,12 @@ tetrahedron22 c =
       fv' = rotate cwz $ rotate ccwy
                        $ rotate ccwy
                        $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedron23 :: Cube -> Tetrahedron
 tetrahedron23 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    Tetrahedron fv' v0' v1' v2' v3' vol
     where
       v0' = center c
       v1' = center (left_face c)
@@ -460,6 +488,7 @@ tetrahedron23 c =
       v3' = Face.v0 (left_face c)
       fv' = rotate cwz $ rotate cwy
                        $ Tetrahedron.fv (tetrahedron0 c)
+      vol = 0
 
 
 tetrahedra :: Cube -> [Tetrahedron]
@@ -489,12 +518,145 @@ tetrahedra c =
      tetrahedron22 c,
      tetrahedron23 c]
 
-
--- | Takes a 'Cube', and returns all Tetrahedra belonging to it that
---   contain the given 'Point'.
-find_containing_tetrahedra :: Cube -> Point -> [Tetrahedron]
-find_containing_tetrahedra c p =
-    filter contains_our_point all_tetrahedra
-    where
-      contains_our_point = flip contains_point p
-      all_tetrahedra = tetrahedra c
+-- | All completely contained in the front half of the cube.
+front_half_tetrahedra :: Cube -> [Tetrahedron]
+front_half_tetrahedra c =
+  [tetrahedron0 c,
+   tetrahedron1 c,
+   tetrahedron2 c,
+   tetrahedron3 c,
+   tetrahedron6 c,
+   tetrahedron12 c,
+   tetrahedron19 c,
+   tetrahedron21 c]
+
+
+-- | All tetrahedra completely contained in the top half of the cube.
+top_half_tetrahedra :: Cube -> [Tetrahedron]
+top_half_tetrahedra c =
+  [tetrahedron4 c,
+   tetrahedron5 c,
+   tetrahedron6 c,
+   tetrahedron7 c,
+   tetrahedron0 c,
+   tetrahedron10 c,
+   tetrahedron16 c,
+   tetrahedron20 c]
+
+
+-- | All tetrahedra completely contained in the back half of the cube.
+back_half_tetrahedra :: Cube -> [Tetrahedron]
+back_half_tetrahedra c =
+  [tetrahedron8 c,
+   tetrahedron9 c,
+   tetrahedron10 c,
+   tetrahedron11 c,
+   tetrahedron4 c,
+   tetrahedron14 c,
+   tetrahedron17 c,
+   tetrahedron23 c]
+
+
+-- | All tetrahedra completely contained in the down half of the cube.
+down_half_tetrahedra :: Cube -> [Tetrahedron]
+down_half_tetrahedra c =
+  [tetrahedron12 c,
+   tetrahedron13 c,
+   tetrahedron14 c,
+   tetrahedron15 c,
+   tetrahedron2 c,
+   tetrahedron8 c,
+   tetrahedron18 c,
+   tetrahedron22 c]
+
+
+-- | All tetrahedra completely contained in the right half of the cube.
+right_half_tetrahedra :: Cube -> [Tetrahedron]
+right_half_tetrahedra c =
+  [tetrahedron16 c,
+   tetrahedron17 c,
+   tetrahedron18 c,
+   tetrahedron19 c,
+   tetrahedron1 c,
+   tetrahedron5 c,
+   tetrahedron9 c,
+   tetrahedron13 c]
+
+
+-- | All tetrahedra completely contained in the left half of the cube.
+left_half_tetrahedra :: Cube -> [Tetrahedron]
+left_half_tetrahedra c =
+  [tetrahedron20 c,
+   tetrahedron21 c,
+   tetrahedron22 c,
+   tetrahedron23 c,
+   tetrahedron3 c,
+   tetrahedron7 c,
+   tetrahedron11 c,
+   tetrahedron15 c]
+
+
+in_top_half :: Cube -> Point -> Bool
+in_top_half c (_,_,z) =
+  distance_from_top <= distance_from_bottom
+  where
+    distance_from_top = abs $ (zmax c) - z
+    distance_from_bottom = abs $ (zmin c) - z
+
+in_front_half :: Cube -> Point -> Bool
+in_front_half c (x,_,_) =
+    distance_from_front <= distance_from_back
+  where
+    distance_from_front = abs $ (xmin c) - x
+    distance_from_back = abs $ (xmax c) - x
+
+
+in_left_half :: Cube -> Point -> Bool
+in_left_half c (_,y,_) =
+    distance_from_left <= distance_from_right
+  where
+    distance_from_left = abs $ (ymin c) - y
+    distance_from_right = abs $ (ymax c) - y
+
+
+-- | Takes a 'Cube', and returns the Tetrahedra belonging to it that
+--   contain the given 'Point'. This should be faster than checking
+--   every tetrahedron individually, since we determine which half
+--   (hemisphere?) of the cube the point lies in three times: once in
+--   each dimension. This allows us to eliminate non-candidates
+--   quickly.
+--
+--   This can throw an exception, but the use of 'head' might
+--   save us some unnecessary computations.
+--
+find_containing_tetrahedron :: Cube -> Point -> Tetrahedron
+find_containing_tetrahedron c p =
+  head containing_tetrahedra
+  where
+    candidates = tetrahedra c
+    non_candidates_x =
+        if (in_front_half c p) then
+          back_half_tetrahedra c
+        else
+          front_half_tetrahedra c
+
+    candidates_x = candidates \\ non_candidates_x
+
+    non_candidates_y =
+      if (in_left_half c p) then
+        right_half_tetrahedra c
+      else
+        left_half_tetrahedra c
+
+    candidates_xy = candidates_x \\ non_candidates_y
+
+    non_candidates_z =
+      if (in_top_half c p) then
+        down_half_tetrahedra c
+      else
+        top_half_tetrahedra c
+
+    candidates_xyz = candidates_xy \\ non_candidates_z
+
+    contains_our_point = flip contains_point p
+    containing_tetrahedra = filter contains_our_point candidates_xyz