我正在为 octree 编写边界框模块图书馆。你可以找到我的分支here .在下面的函数中,我尝试显式显示 Octree
的隐式边界框。问题是,并非所有边界框都有效。
这是有问题的函数,后面是在 ghci
中复制问题的方法。
explicateMBB :: (BBox3, Octree a) -> [BBox3]
explicateMBB (mbb, (Leaf _)) = [mbb]
explicateMBB (mbb, (Node { split = split',
nwu = nwu',
nwd = nwd',
neu = neu',
ned = ned',
swu = swu',
swd = swd',
seu = seu',
sed = sed'
})) =
mbb:concatMap explicateMBB octList
where
octList = zip boxList children
boxList = [swdBox, sedBox, nwdBox, nedBox, swuBox, seuBox, nwuBox, neuBox]
children = [swd',sed',nwd',ned',swu',seu',nwu',neu']
swdBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (minX mbb) (minY mbb) (minZ mbb)
neuCorner = Vector3 (v3x split') (v3y split') (v3z split')
sedBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (v3x split') (minY mbb) (minZ mbb)
neuCorner = Vector3 (maxX mbb) (v3y split') (minZ mbb)
nwdBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (minX mbb) (v3y split') (minZ mbb)
neuCorner = Vector3 (v3x split') (maxY mbb) (v3z split')
nedBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (v3x split') (v3y split') (minZ mbb)
neuCorner = Vector3 (maxX mbb) (maxY mbb) (v3z split')
swuBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (minX mbb) (minY mbb) (v3z split')
neuCorner = Vector3 (v3x split') (v3y split') (maxZ mbb)
seuBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (v3x split') (minY mbb) (v3z split')
neuCorner = Vector3 (maxX mbb) (v3y split') (maxZ mbb)
nwuBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (minX mbb) (v3y split') (v3z split')
neuCorner = Vector3 (v3x split') (maxY mbb) (maxZ mbb)
neuBox = bound_corners swdCorner neuCorner
where
swdCorner = Vector3 (v3x split') (v3y split') (v3z split')
neuCorner = Vector3 (maxX mbb) (maxY mbb) (maxZ mbb)
复制问题:
git clone https://github.com/mlitchard/octree.git
git checkout MBB
堆栈 ghci
在 ghci
中,执行以下操作:
:m + Data.List Data.Vector.Class System.Random System.Random.Shuffle Data.BoundingBox.B3
let infinity = (read "Infinity") :: Double
let swdCorner = Vector3 (-infinity) (-infinity) (-infinity)
let neuCorner = Vector3 (infinity) (infinity) (infinity)
let rbb = bound_corners swdCorner neuCorner
xGen <- getStdGen
yGen <- newStdGen
zGen <- newStdGen
let xPoints = shuffle' [-256 .. 256] 513 xGen
let yPoints = shuffle' [-256 .. 256] 513 yGen
let zPoints = shuffle' [-256 .. 256] 513 zGen
let xPoints' = map fromInteger xPoints :: [Double]
let yPoints' = map fromInteger yPoints :: [Double]
let zPoints' = map fromInteger zPoints :: [Double]
let tup513 = zip3 xPoints' yPoints' zPoints'
let construct_vect = (\(x,y,z) -> Vector3 x y z)
let vect513 = map construct_vect tup513
let pre_oct513 = zip vect513 [1 .. 513]
let octree513 = fromList pre_oct513
length $ filter (== False) $ map isValidMBB $ explicateMBB (rbb,octree513)
答案将是 9,但应该是 0。
我觉得 fooBox
where
子句中的一个是错误的,但我已经对每个子句都进行了多次检查,但我看不出是哪一个。
如果您像我一样需要视觉辅助,我找到了 this pic有帮助。我的示例进行了 2 次分割。
如能深入了解问题出在哪里,我们将不胜感激。
最佳答案
这是你的第二个 where
子句:
where
swdCorner = Vector3 (v3x split') (minY mbb) (minZ mbb)
neuCorner = Vector3 (maxX mbb) (v3y split') (minZ mbb)
应该是:
where
swdCorner = Vector3 (v3x split') (minY mbb) (minZ mbb)
neuCorner = Vector3 (maxX mbb) (v3y split') (v3z split') <-- v3z split'
关于algorithm - 我的边界框功能哪里出了问题?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37932282/