CMake warning about legacy GL library and GLVND libraries for OpenGL and GLX.

[Htet-Wai-Yan-HWY]

I am trying to use xbox 360 depth camera in ubuntu 22.04. When I build this project , cmake show following warning and error.

`zyme@dev:~/libfreenect/build$ cmake -L ..
CMake Deprecation Warning at CMakeLists.txt:33 (cmake_minimum_required):
  Compatibility with CMake < 2.8.12 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value or use a ...<max> suffix to tell
  CMake that the project does not need compatibility with older versions.


-- Operating system is Linux
-- Got System Processor x86_64
-- Linux x86_64 Detected
-- libfreenect will be installed to /usr/local
-- Headers will be installed to /usr/local/include/libfreenect
-- Libraries will be installed to /usr/local/lib
-- Found libusb-1.0:
--  - Includes: /usr/include/libusb-1.0
--  - Libraries: /usr/lib/x86_64-linux-gnu/libusb-1.0.so
CMake Warning (dev) at /usr/share/cmake-3.22/Modules/FindOpenGL.cmake:315 (message):
  Policy CMP0072 is not set: FindOpenGL prefers GLVND by default when
  available.  Run "cmake --help-policy CMP0072" for policy details.  Use the
  cmake_policy command to set the policy and suppress this warning.

  FindOpenGL found both a legacy GL library:

    OPENGL_gl_LIBRARY: /usr/lib/x86_64-linux-gnu/libGL.so

  and GLVND libraries for OpenGL and GLX:

    OPENGL_opengl_LIBRARY: /usr/lib/x86_64-linux-gnu/libOpenGL.so
    OPENGL_glx_LIBRARY: /usr/lib/x86_64-linux-gnu/libGLX.so

  OpenGL_GL_PREFERENCE has not been set to "GLVND" or "LEGACY", so for
  compatibility with CMake 3.10 and below the legacy GL library will be used.
Call Stack (most recent call first):
  examples/CMakeLists.txt:55 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Checking for module 'glut'
--   No package 'glut' found
CMake Warning (dev) at /usr/share/cmake-3.22/Modules/FindOpenGL.cmake:315 (message):
  Policy CMP0072 is not set: FindOpenGL prefers GLVND by default when
  available.  Run "cmake --help-policy CMP0072" for policy details.  Use the
  cmake_policy command to set the policy and suppress this warning.

  FindOpenGL found both a legacy GL library:

    OPENGL_gl_LIBRARY: /usr/lib/x86_64-linux-gnu/libGL.so

  and GLVND libraries for OpenGL and GLX:

    OPENGL_opengl_LIBRARY: /usr/lib/x86_64-linux-gnu/libOpenGL.so
    OPENGL_glx_LIBRARY: /usr/lib/x86_64-linux-gnu/libGLX.so

  OpenGL_GL_PREFERENCE has not been set to "GLVND" or "LEGACY", so for
  compatibility with CMake 3.10 and below the legacy GL library will be used.
Call Stack (most recent call first):
  wrappers/cpp/CMakeLists.txt:25 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Checking for module 'glut'
--   No package 'glut' found
-- Configuring done
-- Generating done
-- Build files have been written to: /home/zyme/libfreenect/build
-- Cache values
BUILD_AS3_SERVER:BOOL=OFF
BUILD_CPACK_DEB:BOOL=OFF
BUILD_CPACK_RPM:BOOL=OFF
BUILD_CPACK_TGZ:BOOL=OFF
BUILD_CPP:BOOL=ON
BUILD_CV:BOOL=OFF
BUILD_C_SYNC:BOOL=ON
BUILD_EXAMPLES:BOOL=ON
BUILD_FAKENECT:BOOL=ON
BUILD_OPENNI2_DRIVER:BOOL=OFF
BUILD_PYTHON:BOOL=OFF
BUILD_REDIST_PACKAGE:BOOL=ON
CMAKE_BUILD_TYPE:STRING=
CMAKE_INSTALL_PREFIX:PATH=/usr/local
LIBUSB_1_INCLUDE_DIR:PATH=/usr/include/libusb-1.0
LIBUSB_1_LIBRARY:FILEPATH=/usr/lib/x86_64-linux-gnu/libusb-1.0.so
`

I have glut library under "/usr/include/GL" but it shows No package 'glut' found

[piedar]

CMake Deprecation Warning at CMakeLists.txt:33 (cmake_minimum_required):
  Compatibility with CMake < 2.8.12 will be removed from a future version of
  CMake.

This should be fixed by #678.

  FindOpenGL found both a legacy GL library:

    OPENGL_gl_LIBRARY: /usr/lib/x86_64-linux-gnu/libGL.so

  and GLVND libraries for OpenGL and GLX:

    OPENGL_opengl_LIBRARY: /usr/lib/x86_64-linux-gnu/libOpenGL.so
    OPENGL_glx_LIBRARY: /usr/lib/x86_64-linux-gnu/libGLX.so

  OpenGL_GL_PREFERENCE has not been set to "GLVND" or "LEGACY", so for
  compatibility with CMake 3.10 and below the legacy GL library will be used.

This one doesn't make sense to me. We've been setting OpenGL_GL_PREFERENCE GLVND since f6de60f more than a year ago. Are you compiling an older version of libfreenect? Maybe #678 will help anyway...

-- Checking for module 'glut'
--   No package 'glut' found

This one I have no idea. It works on my machine where the freeglut package provides these files.

/usr/include/GL/freeglut.h
/usr/include/GL/freeglut_ext.h
/usr/include/GL/freeglut_std.h
/usr/include/GL/freeglut_ucall.h
/usr/include/GL/glut.h
/usr/lib64/cmake/FreeGLUT/FreeGLUTConfig.cmake
/usr/lib64/cmake/FreeGLUT/FreeGLUTConfigVersion.cmake
/usr/lib64/cmake/FreeGLUT/FreeGLUTTargets-relwithdebinfo.cmake
/usr/lib64/cmake/FreeGLUT/FreeGLUTTargets.cmake
/usr/lib64/libglut.so -> libglut.so.3
/usr/lib64/libglut.so.3 -> libglut.so.3.12.0
/usr/lib64/libglut.so.3.12.0
/usr/lib64/pkgconfig/freeglut.pc
/usr/lib64/pkgconfig/glut.pc