Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Normals Having No Effect???

  1. #1
    Member Contributor
    Join Date
    Aug 2001
    Posts
    62

    Normals Having No Effect???

    im writing a GL modelviewer and im stuck as to why the model(a ball) has a massive bright spot and the opposite side is dull...
    now i know what you thinkin the fools got his normals backwards on the dim side,
    but i dont think thats it since, when i dont use my normals the same thing happens, and the light isn't moving. it also has several extremely bright spots in various locations(my guess is specular problems)????

    ive written similar programs many o' times and ive never had this problem ever!!!

    and pretaining to the topic name MY NORMALS HAVE NO EFFECT AT ALL...

    thanks,

    [This message has been edited by no-one (edited 08-28-2001).]

  2. #2
    Junior Member Newbie
    Join Date
    Aug 2001
    Posts
    1

    Re: Normals Having No Effect???

    Hi,

    I am not an expert in OpenGL yet but I may be able to help.

    You stated that it is bright on one side and dark on the other. You also said that the light does not move.

    One problem could be that you are transforming the light as well as your model on each rendering pass, this will cause the light to move with the model (the spot never moves).

    I hope that helped.

  3. #3
    Junior Member Newbie
    Join Date
    Aug 2001
    Location
    Thessaloniki,Macedonia,Greece
    Posts
    11

    Re: Normals Having No Effect???

    Hey, it has nothing to do with the normal vectors -they are fine!The normal vectors are defined very well by the function that draws sphere.You are not supposed to redefine them!Your problem has to do with the light's position and settings.The problem is there-good luck

  4. #4
    Member Contributor
    Join Date
    Aug 2001
    Posts
    62

    Re: Normals Having No Effect???

    hkyProgrammer,

    actually they are moved(if the light moves) seperatly using matrix pushes...
    thanks though.

    Paulus,
    >Your problem has to do with the light's position and settings.The problem is there-good luck<

    settings match old working programs, and the position in this case doesnt change... i cant figure it out ive ben on this for 2 weeks...
    do you have any idea what setting could cause this i have no clue?????

    and thank you once again.

    [This message has been edited by no-one (edited 08-28-2001).]

  5. #5
    Member Contributor
    Join Date
    Aug 2001
    Posts
    62

    Re: Normals Having No Effect???

    and BTW: this might help so...
    the smooth shading looks like crap also it lights the edges of the polygons brighter than the centers so it looks kinda nasty and this is abnormal...

  6. #6
    Junior Member Newbie
    Join Date
    Aug 2001
    Location
    Thessaloniki,Macedonia,Greece
    Posts
    11

    Re: Normals Having No Effect???

    If you use the glScale function then you have to enable automatic renormalization of vectors using glEnable(GL_NORMALIZE) -have you tried that?If you do not then what you describe is natural.

  7. #7
    Member Contributor
    Join Date
    Aug 2001
    Posts
    62

    Re: Normals Having No Effect???

    >If you use the glScale function then you have to enable automatic renormalization of vectors using glEnable(GL_NORMALIZE) -have you tried that?If you do not then what you describe is natural.<

    glScale is never used anywhere not eventyped anywhere...

  8. #8
    Senior Member OpenGL Guru zed's Avatar
    Join Date
    Nov 2010
    Posts
    2,466

    Re: Normals Having No Effect???

    >>im writing a GL modelviewer and im stuck as to why the model(a ball) has a massive bright spot and the opposite side is dull...
    now i know what you thinkin the fools got his normals backwards on the dim side,<<

    a bit o a strange question, thjis is normal behaviour if u want the other side lit as well either stick another light on the the other side or increase the first lights ambient coour

  9. #9
    Member Contributor
    Join Date
    Aug 2001
    Posts
    62

    Re: Normals Having No Effect???

    actually only the object moves the light remains constant i have verified this with other objects yet all have the same problem with the bright and dark spots...

    glPushMatrix()
    //rotate then draw the object
    glPopMatrix()
    //draw the light

    light doesnt move... all sides of the object should be lit evenly as it rotates

  10. #10
    Senior Member OpenGL Pro
    Join Date
    Jun 2000
    Location
    Shreveport, LA, USA
    Posts
    1,502

    Re: Normals Having No Effect???

    If you do a search on this board you should find a complete program I posted for someone else that draws a light revolving around a sphere. It might be of some use to you.

Page 1 of 2 12 LastLast

Similar Threads

  1. Replies: 6
    Last Post: 04-14-2004, 10:07 PM
  2. face normals or vertex normals
    By infinitecmdz in forum OpenGL: Advanced Coding
    Replies: 4
    Last Post: 02-21-2004, 07:29 AM
  3. vertex normals or face normals
    By infinitecmdz in forum OpenGL: Basic Coding
    Replies: 2
    Last Post: 02-20-2004, 09:35 AM
  4. is it possible to have vertex normals or even face normals using triangle strips nt
    By wildeyedboyfromfreecloud in forum OpenGL: Advanced Coding
    Replies: 63
    Last Post: 03-19-2002, 11:42 PM
  5. Face Normals vs. Vertex Normals
    By detzel in forum OpenGL: Advanced Coding
    Replies: 6
    Last Post: 03-05-2001, 10:50 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Proudly hosted by Digital Ocean