<pre>Hi everyone,<br><br>Someone please help me with this vtkLookupTable problem. I was trying all weekend but cannot figure out what I am doing wrong!<br><br>I am constructing a vtkLookupTable manually as follows:<br><br>
double * range = reader->GetOutput()->GetScalarRange();<br>vtkLookupTable * greenMap = vtkLookupTable::New();<br>greenMap->SetNumberOfTableValues(256);<br>greenMap->Build();<br><br>double i = 0.0;<br><br>for(int index=0;index<256;index++)
<br>{<br> greenMap->SetTableValue(index, 0.0, i/256.0, 0.0, 1.0);<br> i++;<br>}<br>greenMap->SetAlphaRange(1.0,1.0);<br><br>greenMap->SetTableRange(range[0], range[1]);<br>colorMapper->SetLookupTable(greenMap);
<br>colorMapper->Update();<br><br><br>I see nothing but a black screen. However, when I generate the table for<br>red... like:<br><br>double * range = reader->GetOutput()->GetScalarRange();<br>vtkLookupTable * redMap = vtkLookupTable::New();
<br>redMap->SetNumberOfTableValues(256);<br>redMap->Build();<br><br>double i = 0.0;<br><br>for(int index=0;index<256;index++)<br>{<br> redMap->SetTableValue(index, 0.0, i/256.0, 0.0, 1.0);<br> i++;<br>
}<br>redMap->SetAlphaRange(1.0,1.0);<br><br>redMap->SetTableRange(range[0], range[1]);<br>colorMapper->SetLookupTable(redMap);<br>colorMapper->Update();<br><br><br>then my image is mapped correctly to red values...
<br><br>It is weird...red and gray color maps work but not green and blue!!<br><br>Can someone help me find what the problem is...it is driving me nuts and it is quite urgent. I really beg for some direction here.<br><br>
Thanks,<br><br>Luca</pre>