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Thread: Retrieving Coordinates after rotations

  1. #1
    Intern Contributor
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    Feb 2000
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    Stafford, UK
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    Retrieving Coordinates after rotations

    Hi all,

    I am rotating my camera using GlRotatef which works fine, but once I have rotated how do I get the new coordinates?, same goes for objects...

    thanks

  2. #2
    Junior Member Regular Contributor
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    Feb 2000
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    124

    Re: Retrieving Coordinates after rotations

    I don't know, but I'm also very interested in it. If you find/get an answer, please let me know.

    Thx

  3. #3
    Guest

    Re: Retrieving Coordinates after rotations

    Hi !
    I`m working on a project that enables 3d navigation in a closed box.
    I`ve created a class called camera and it is responsible for the rotation , and the different moves of the camera
    if you think it is suitable for you !!

  4. #4
    Intern Contributor
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    Re: Retrieving Coordinates after rotations

    gvilir - Yes that would be great, if you could post it here or mail it, thanks.

    Marc, once I find out I'll tell you!, post me your mail address.

  5. #5

    Re: Retrieving Coordinates after rotations

    It's not possible to get those transformed coordinates in OpenGL.
    Just think the hardware case, how on earth could you access the data on the cards pipeline?
    Or using several glVertex calls. IF there was some glGetTransformedVertex function, you should call it after each glVertex call. Doesn't sound too nice.
    I think it could be possible to make this with some kind of vertex array extension where you can pass OpenGL source and destination arrays. But afaik there is now such thing...

  6. #6
    Guest

    Re: Retrieving Coordinates after rotations

    Hi david !
    it seems that your email adress is wrong or something like this .

  7. #7
    Junior Member Regular Contributor
    Join Date
    Feb 2000
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    124

    Re: Retrieving Coordinates after rotations

    David, my e-mail-address is available in the profiles-section (left one of the four icons on top of postings of registered contributors). But here it is, too:
    m.schneider@oe.uni-duisburg.de

    thx for your offer

  8. #8

    Re: Retrieving Coordinates after rotations

    Just thought about something...

    You could use glProject, but it's not a very good solution...

  9. #9
    Intern Contributor
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    France
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    Re: Retrieving Coordinates after rotations

    I can't believe what I saw ! Of course you can get the final coordinates of your points ! Have you ever heard of feedback mode ???
    Antoche

  10. #10

    Re: Retrieving Coordinates after rotations

    Doh, the problem is that you can't render while in feedback mode! So, you would have to switch into feedback mode, do the stuff you like, switch back to render mode...

    Oh yes, and it's in window coordinates.

    [This message has been edited by Hude (edited 03-05-2000).]

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