Re: [Plplot-devel] plotsh3d changes

[Maurice L. <mj...@ga...>]

Gary Bishop writes:
 > Hi,
 > 
 > Alan asked me to follow up to the list with a brief description of what 
 > I did to fix the "missing triangles bug" in plotsh3d.
 > 
 > The old code attempted to modify the hidden-line algorithm to do hidden 
 > surfaces. This is very difficult. Hidden-line algorithms are much more 
 > complicated than hidden-surface algorithms. So much so that the modern 
 > way to do hidden lines is with a hidden-surface algorithm that draws 
 > polygons that have their edges shaded and their middles background colored.

Yeah, the old way seemed to be one of those problems that was theoretically
possible, but would probably drive you nuts trying to figure it out.  And
definitely not worth the time.

 > I didn't want to fool with the hidden-line algorithm so I wrote a 
 > completely separate algorithm for doing the hidden surface removal. I'm 
 > using a simple back-to-front ("painters") algorithm. I figure out which 
 > is the back most corner of the data and work toward the front from there.

It looks great, thanks.

-- 
Maurice LeBrun    mj...@ga...
Research Organization for Information Science and Technology of Japan (RIST)