PolyVox currently compiles on OpenSUSE and Fedora, both using Qt packages from the official repositories. There is no reason why it shouldn't work in principle in Ubuntu.
It's possible there's a bug in the older version of CMake you're using (and if there is then we might have to raise the requirement). What version do you have?
Also, could you give the output of
make VERBOSE=1 in the terminal from the build directory as that will print the actual include directories the compiler is seeing. For example, if I do it on my machine I see the following at the end:
Code:
[ 92%] Building CXX object examples/Basic/CMakeFiles/BasicExample.dir/OpenGLWidget.cpp.o
cd /home/matt/polyvox/build/examples/Basic && /usr/bin/c++ -DQT_CORE_LIB -DQT_GUI_LIB -DQT_OPENGL_LIB -DQT_WIDGETS_LIB -g -fPIE -I/home/matt/polyvox/build/library/PolyVoxCore/include -I/home/matt/polyvox/library/PolyVoxCore/include -I/usr/include/qt5 -I/usr/include/qt5/QtOpenGL -I/usr/include/qt5/QtWidgets -I/usr/include/qt5/QtGui -I/usr/include/qt5/QtCore -I/usr/lib64/qt5/mkspecs/linux-g++ -std=c++0x -o CMakeFiles/BasicExample.dir/OpenGLWidget.cpp.o -c /home/matt/polyvox/examples/Basic/OpenGLWidget.cpp
and you can see that one of the options given to g++ is
-I/usr/include/qt5/QtOpenGL which is where it's looking for QGLWidget.