+{-# INLINE zoom_chunk_lookup #-}
+zoom_chunk_lookup :: Grid -> ScaleFactor -> a -> (R.DIM3 -> Double)
+zoom_chunk_lookup g scale_factor _ =
+ zoom_chunk_result g scale_factor
+
+
+{-# INLINE zoom_chunk_result #-}
+zoom_chunk_result :: Grid -> ScaleFactor -> R.DIM3 -> Double
+zoom_chunk_result g (sfx, sfy, sfz) (R.Z R.:. m R.:. n R.:. o)
+ | m /= 1 = 0 -- We're going to drop these anyway.
+ | otherwise = f p
+ where
+ offset = (h g)/2
+ sfx' = fromIntegral sfx
+ sfy' = fromIntegral sfy
+ sfz' = fromIntegral sfz
+ m' = (fromIntegral m) / sfx' - offset
+ n' = (fromIntegral n) / sfy' - offset
+ o' = (fromIntegral o) / sfz' - offset
+ p = (m', n', o') :: Point
+ cube = find_containing_cube g p
+ t = find_containing_tetrahedron cube p
+ f = polynomial t
+
+
+zoom_chunk :: Grid -> ScaleFactor -> Values3D
+zoom_chunk g scale_factor
+ | xsize == 0 || ysize == 0 || zsize == 0 = empty3d
+ | otherwise =
+ R.force $ R.unsafeTraverse arr transExtent (zoom_chunk_lookup g scale_factor)
+ where
+ arr = function_values g
+ (xsize, ysize, zsize) = dims arr
+ transExtent = zoom_shape scale_factor
+
+
+