Am 06.08.2011 13:12, schrieb mukesh tiwari:
Hello all , Hi I am trying to understand rotating calipers [ http://en.wikipedia.org/wiki/Rotating_calipers ] but i am not sure if understood this algorithm correctly . I tried to use the almost same algorithm given on wiki but with four calipers to solve the problem [ http://cgm.cs.mcgill.ca/~orm/rotcal.html ]. There are several algorithms mentioned on that page. Do you need the diameter, width, or something else?
My approach is find xminP, xmaxP, yminP ymaxP and their corresponding calipers will be ( 0 * i - j ) , ( o * i + j ) , ( i + 0 * j ) and ( -i + 0 * j ). I implemented the algorithm in Haskell but its not working . I am not sure if i have followed the wiki algorithm correctly and could some one please tell me what is wrong with implementation. It would be great if some one can explain this algorithm in pseudo code which explains the rotating caliper and their implementation details . In case of indentation , see here [ http://hpaste.org/49907 ] . Thank you Mukesh Tiwari
I tried your code on one of my libraries. The convex hull function seems to works correctly (I could send you a screenshot). I hope this narrows the search down. Do you have some example data and what wrong result you get? In one of my libraries (http://hackage.haskell.org/packages/archive/collada-types/0.3/doc/html/Graph...) there is a function: streamAnimation :: [(Float,Float,Float)] -> [SceneNode] -> [Animation] that can visualize a stream of points by an animation. I use this sometimes for debugging. -Tillmann