theta :: Double
theta = 0.0000000000001
+
-- | x almost equals y if x is within 'theta' of y.
+--
+-- Only used in tests.
+--
nearly_equals :: Double -> Double -> Bool
-nearly_equals x y = (abs (x - y)) < theta
+nearly_equals x y =
+ (abs (x - y)) < theta
+
-- | Nearly greater-than or equal-to.
+--
+-- Only used in tests.
+--
nearly_ge :: Double -> Double -> Bool
-x `nearly_ge` y = (x > y) || (x `nearly_equals` y)
+x `nearly_ge` y =
+ (x > y) || (x `nearly_equals` y)
+
-- | x almost equals y if x is within 'epsilon' of y.
+--
+-- Only used in tests.
+--
almost_equals :: Double -> Double -> Bool
-almost_equals x y = (abs (x - y)) < epsilon
+almost_equals x y =
+ (abs (x - y)) < epsilon
infix 4 ~=
(~=) :: Double -> Double -> Bool
-- | Like 'almost_equals', except much more tolerant. The difference
-- between the two arguments must be less than one percent of the sum
-- of their magnitudes.
+--
+-- Only used in tests.
+--
kinda_equals :: Double -> Double -> Bool
kinda_equals x y =
- (abs (x - y)) < threshold
- where
- threshold = ((abs x) + (abs y)) / 100.0
+ (abs (x - y)) < threshold
+ where
+ threshold = ((abs x) + (abs y)) / 100.0
infix 4 ~~=
(~~=) :: Double -> Double -> Bool
-- | x is very positive if it is 'epsilon' greater than zero.
+--
+-- Only used in tests.
+--
very_positive :: Double -> Bool
-very_positive x = x - epsilon > 0
+very_positive x =
+ x - epsilon > 0
-- | Takes a list of 'Double' and returns the ones which are not very
center (Tetrahedron _ v0' v1' v2' v3' _) =
(v0' + v1' + v2' + v3') `scale` (1/4)
+ -- contains_point is only used in tests.
contains_point t p0 =
b0_unscaled `nearly_ge` 0 &&
b1_unscaled `nearly_ge` 0 &&