Part of the Khronos Group
OpenGL.org

The Industry's Foundation for High Performance Graphics

from games to virtual reality, mobile phones to supercomputers

Results 1 to 5 of 5

Thread: Lighting problem, jaggy looking edges

  1. #1
    Junior Member Regular Contributor
    Join Date
    Sep 2000
    Posts
    139

    Lighting problem, jaggy looking edges



    When I look at the sphere from certain angles I see the edges of the polygons showing like in the first panel. But other view points aren't so ugly, does anyone recognize what this problem is?

  2. #2
    Junior Member Newbie
    Join Date
    Jun 2001
    Posts
    29

    Re: Lighting problem, jaggy looking edges

    maybe I know what the problem is, but could you give me alink to a more recognizable screenshot ? dark blue on black is not very good.

    --styx

  3. #3
    Junior Member Regular Contributor
    Join Date
    Sep 2000
    Posts
    139

    Re: Lighting problem, jaggy looking edges


  4. #4
    Junior Member Newbie
    Join Date
    Jun 2001
    Posts
    29

    Re: Lighting problem, jaggy looking edges

    hmm, that looks really weird.
    I had such a problem with specular highlights, because opengl can not render hightlights on areas but only along edges so highlights often look like this (except you make the highlight less intensive or use *masses* of polys)
    are you sure your material properties are setup correctly, reflectance etc... ?
    did you give the material a specular color or only ambient/diffuse ?

    --styx

  5. #5
    Junior Member Regular Contributor
    Join Date
    Oct 2001
    Location
    Holland
    Posts
    179

    Re: Lighting problem, jaggy looking edges

    Grady,

    This may be caused by the way the highlights are calculated by OpenGL. The normals of the vertices are used to determine if the light shines on a vertex or not, and if so, how intense the highlight is.
    From the sreenshot it looks like the jaggies appear for those quads/triangles of the sphere where the normals of the lower vertices are at an angle > 90 degrees with the vertex-to-lightsource vector.
    That means that those vertices do not receive any light --> black

    Also, are you sure the sphere is not clipped by the near plane?

    HTH

    Jean-Marc.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •