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Thread: normal rescaling

  1. #1
    Senior Member Regular Contributor
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    normal rescaling

    about GL_RESCALE_NORMAL... is it a opengl 1.2 spec?

    Dolo/\/\ightY
    Dolo/\/\ightY

  2. #2
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    Re: normal rescaling

    just found this in one of Mark Kilgard's
    article

    "OpenGL 1.2 adds a new glEnable mode called GL_RESCALE_NORMAL"

  3. #3
    Senior Member Regular Contributor
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    Re: normal rescaling

    thanks mike. another thing: in my application i render planets from unit spheres. as you know, vertex and vertex normals are equal vectors for such a sphere.
    so, i uniform scale to the size i need, and obviously opengl scales the normals too.
    so, i enable GL_NORMALIZE and what i find?
    everything renders good.
    and performance?
    performances are the same! more, when normalization is enabled the application is faster, about 1 fps more !

    the card is a geforce.
    the tnt have the same behaviour.
    the sphere has 950 verts and 1600 faces (more or less)
    i use a vertex list to send data.

    now i'll test on a g200, and i'll try out a bigger model and straight opengl soon, to see if i'm near the point where the speed of data send and normalizations become comparable.

    any experiences about that?

    tnx

    Dolo/\/\ightY



    [This message has been edited by dmy (edited 02-25-2000).]
    Dolo/\/\ightY

  4. #4
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    Re: normal rescaling

    I'm using triangles to create some funky looking spheres in my current project and its pretty much the same as the example code
    out of the redbook - the chapter where a sphere is created by subdivision and yes I
    had to scale them down

    I just put it in a display list

    // innermost spikeball
    glNewList(dList+2, GL_COMPILE);
    glEnable(GL_NORMALIZE);
    glScalef(0.25f, 0.25f, 0.25f);
    drawSpikeBall();
    glDisable(GL_NORMALIZE);
    glEndList();

    if you want to see what it looks like I released as a screensaver a few months ago http://www.3dfiles.com/screensavers/borealis2.shtml

    I'm starting to do a rework because I've gotten emails from GeForce owners about the
    problems in our previous discussion

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