<div dir="ltr">Hello,<br><br>Yes we were suffering the same issue.<div>I believe the change occurred with this commit<br><a 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 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 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></div></div><div><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 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^{<span style="display:inline-block;width:0;min-height:0;overflow:hidden">^</span>3}.
                  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>
              </blockquote>
            </div>
            <br>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
  </div></div></div>

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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div>------------------------------------------------------------------<br>Simon Esneault<div>Rennes, France<br>------------------------------------------------------------------</div></div></div></div>
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