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Thread: read back transformed vertex coordinates...

  1. #1
    Junior Member Newbie
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    Feb 2004
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    3

    read back transformed vertex coordinates...

    Hi,

    Is there any way of reading back the vertex coordinates after specifying a series of affine transformations in OpenGL? If so, how?

    -daniel

  2. #2
    Senior Member Regular Contributor
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    Jan 2004
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    Los Angeles, CA, USA
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    Re: read back transformed vertex coordinates...

    I think you want to look into gluProject().

  3. #3
    Junior Member Newbie
    Join Date
    Feb 2004
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    3

    Re: read back transformed vertex coordinates...

    But gluProject() needs the viewport to be specified. I want the coordinates of the transformed vertices in world coordinate, i.e. after model and viewing transformations. I do not want to write a set of transformation routines that do the work that is plausibly be done with OpenGL or related libraries.

    As a matter of fact, I am trying to cook up some code to parse scene files; and in the scene file, I can specify transformations on polygons instead of stating the absolute world coordinates of these polygon vertices, presumably for easier modeling.

    I need transformed vertex coordinates since that would be easier when I do radiosity algorithm.

    -Daniel.

    Originally posted by endash:
    I think you want to look into gluProject().

  4. #4
    Senior Member Regular Contributor
    Join Date
    Oct 2001
    Location
    Princeton, NJ
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    380

    Re: read back transformed vertex coordinates...

    look into feedback mode, there is an entire chapter in the redbook devoted to feedback and selection

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