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    <div class="moz-cite-prefix">Thank you very much for confirming the
      problem and related information.<br>
      <br>
      Best,<br>
      Weiguang<br>
      <br>
      On 14/09/2015 10:48 AM, Simon ESNEAULT wrote:<br>
    </div>
    <blockquote
cite="mid:CAC9gB0DAWQ6oJhOsGTJQVY4W7egV8BnqfEtdkCBMA1_2sBuZfg@mail.gmail.com"
      type="cite">
      <div dir="ltr">Hello,<br>
        <br>
        Yes we were suffering the same issue.
        <div>I believe the change occurred with this commit<br>
          <a moz-do-not-send="true"
href="https://github.com/Kitware/VTK/commit/0164fa1e25d9c584e7ec60acb7e221f7ea9e5d7c">https://github.com/Kitware/VTK/commit/0164fa1e25d9c584e7ec60acb7e221f7ea9e5d7c</a><br>
          The 128x256x256 thing is no longer hard coded, it now relies
          on the vtkgl::MAX_3D_TEXTURE_SIZE variable to compute a
          correct reduction ratio, which will lead to this significant
          slow down.</div>
        <div><br>
          Some more explanations :<br>
          <a moz-do-not-send="true"
            href="http://marc.info/?l=vtkusers&m=128869084800678">http://marc.info/?l=vtkusers&m=128869084800678</a></div>
        <div><br>
          The Volume Texture Mapper 3D has just been marked as
          deprecated so I don't think there will be any sort of fix, but
          you should be able to restore the old behavior if you look to
          the commit, and revert the changes made in the method
          <div>int
            vtkOpenGLVolumeTextureMapper3D::IsTextureSizeSupported(int
            size[3], int components){...}<br>
            <br>
            Best Regards<br>
            Simon<br>
            <br>
            <br>
          </div>
          <div class="gmail_extra"><br>
            <div class="gmail_quote">2015-09-14 15:55 GMT+02:00 Weiguang
              guan <span dir="ltr"><<a moz-do-not-send="true"
                  href="mailto:guanw@rhpcs.mcmaster.ca" target="_blank">guanw@rhpcs.mcmaster.ca</a>></span>:<br>
              <blockquote class="gmail_quote" style="margin:0 0 0
                .8ex;border-left:1px #ccc solid;padding-left:1ex">
                <div text="#000000" bgcolor="#FFFFFF">
                  <div>Hi David,<br>
                    <br>
                    I'll try vtkImageResize. Thanks.<br>
                    <br>
                    Best,<br>
                    Weiguang
                    <div>
                      <div class="h5"><br>
                        <br>
                        On 11/09/2015 1:48 PM, David Gobbi wrote:<br>
                      </div>
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                    <div class="h5">
                      <blockquote type="cite">
                        <div dir="ltr">Hi Weiguang,
                          <div><br>
                          </div>
                          <div>You can do the image resizing as a
                            preliminary step with vtkImageResize, which
                            does efficient band-limited sinc
                            interpolation and can do a good job of
                            shrinking the image without introducing
                            aliasing artifacts.</div>
                          <div><br>
                          </div>
                          <div>Hopefully someone else will answer your
                            question about vtkVolumeTextureMapper3D (I
                            haven't used it in a while).</div>
                          <div><br>
                          </div>
                          <div> - David<br>
                            <div class="gmail_extra"><br>
                              <div class="gmail_quote">On Fri, Sep 11,
                                2015 at 11:22 AM, Weiguang guan <span
                                  dir="ltr"><<a
                                    moz-do-not-send="true"
                                    href="mailto:guanw@rhpcs.mcmaster.ca"
                                    target="_blank">guanw@rhpcs.mcmaster.ca</a>></span>
                                wrote:<br>
                                <blockquote class="gmail_quote"
                                  style="margin:0 0 0
                                  .8ex;border-left:1px #ccc
                                  solid;padding-left:1ex">
                                  <div text="#000000" bgcolor="#FFFFFF">
                                    Hello VTK users, <br>
                                    <br>
                                    We develop a viz system using
                                    vtkVolumeTextureMapper3D for volume
                                    rendering. Recently, we've moved up
                                    from v5.1 to v6.2. After that, we
                                    notice our viz system has a
                                    significant slow-down in rendering
                                    speed (compared on the same
                                    computer) when volume size is large,
                                    say LxWxH ~= 512<sup><span
                                        style="display:inline-block;width:0;min-height:0;overflow:hidden">^</span>3</sup>.
                                    It can always render small volumes
                                    at interactive rate. <br>
                                    <br>
                                    I know that vtkVolumeTextureMapper3D
                                    needs to resample large volume to
                                    fit in 128*256*256 (BTW, our data is
                                    regular volume data with a single
                                    component). But this down-sampling
                                    process is not new in 6.2. Are there
                                    other changes that cause the
                                    performance issue? Does anyone
                                    experience the same issue? Thanks. <br>
                                    <br>
                                    Best, <br>
                                    Weiguang</div>
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            </div>
            -- <br>
            <div class="gmail_signature">
              <div dir="ltr">
                <div>------------------------------------------------------------------<br>
                  Simon Esneault
                  <div>Rennes, France<br>
------------------------------------------------------------------</div>
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