# - Try to find OpenGL
# Once done this will define
#
#  OPENGL_FOUND        - system has OpenGL
#  OPENGL_XMESA_FOUND  - system has XMESA
#  OPENGL_GLU_FOUND    - system has GLU
#  OPENGL_INCLUDE_DIR  - the GL include directory
#  OPENGL_LIBRARIES    - Link these to use OpenGL and GLU
#
# If you want to use just GL you can use these values
#  OPENGL_gl_LIBRARY   - Path to OpenGL Library
#  OPENGL_glu_LIBRARY  - Path to GLU Library
#
# On OSX default to using the framework version of opengl
# People will have to change the cache values of OPENGL_glu_LIBRARY
# and OPENGL_gl_LIBRARY to use OpenGL with X11 on OSX

#=============================================================================
# Copyright 2001-2009 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
#  License text for the above reference.)

if (WIN32)
  if (CYGWIN)

    find_path(OPENGL_INCLUDE_DIR GL/gl.h )

    find_library(OPENGL_gl_LIBRARY opengl32 )

    find_library(OPENGL_glu_LIBRARY glu32 )

  else ()

    if(BORLAND)
      set (OPENGL_gl_LIBRARY import32 CACHE STRING "OpenGL library for win32")
      set (OPENGL_glu_LIBRARY import32 CACHE STRING "GLU library for win32")
    else()
      set (OPENGL_gl_LIBRARY opengl32 CACHE STRING "OpenGL library for win32")
      set (OPENGL_glu_LIBRARY glu32 CACHE STRING "GLU library for win32")
    endif()

  endif ()

else ()

  if (APPLE)

    find_library(OPENGL_gl_LIBRARY OpenGL DOC "OpenGL lib for OSX")
    find_library(OPENGL_glu_LIBRARY AGL DOC "AGL lib for OSX")
    find_path(OPENGL_INCLUDE_DIR OpenGL/gl.h DOC "Include for OpenGL on OSX")

  else()
    if (CMAKE_SYSTEM_NAME MATCHES "HP-UX")
      # Handle HP-UX cases where we only want to find OpenGL in either hpux64
      # or hpux32 depending on if we're doing a 64 bit build.
      if(CMAKE_SIZEOF_VOID_P EQUAL 4)
        set(_OPENGL_LIB_PATH
          /opt/graphics/OpenGL/lib/hpux32/)
      else()
        set(_OPENGL_LIB_PATH
          /opt/graphics/OpenGL/lib/hpux64/
          /opt/graphics/OpenGL/lib/pa20_64)
      endif()
    elseif(CMAKE_SYSTEM_NAME STREQUAL Haiku)
      set(_OPENGL_LIB_PATH
        /boot/develop/lib/x86)
      set(_OPENGL_INCLUDE_PATH
        /boot/develop/headers/os/opengl)
    endif()

    # The first line below is to make sure that the proper headers
    # are used on a Linux machine with the NVidia drivers installed.
    # They replace Mesa with NVidia's own library but normally do not
    # install headers and that causes the linking to
    # fail since the compiler finds the Mesa headers but NVidia's library.
    # Make sure the NVIDIA directory comes BEFORE the others.
    #  - Atanas Georgiev <atanas@cs.columbia.edu>

    find_path(OPENGL_INCLUDE_DIR GL/gl.h
      /usr/share/doc/NVIDIA_GLX-1.0/include
      /usr/openwin/share/include
      /opt/graphics/OpenGL/include /usr/X11R6/include
      ${_OPENGL_INCLUDE_PATH}
    )

    find_path(OPENGL_xmesa_INCLUDE_DIR GL/xmesa.h
      /usr/share/doc/NVIDIA_GLX-1.0/include
      /usr/openwin/share/include
      /opt/graphics/OpenGL/include /usr/X11R6/include
    )

    find_library(OPENGL_gl_LIBRARY
      NAMES GL MesaGL
      PATHS /opt/graphics/OpenGL/lib
            /usr/openwin/lib
            /usr/shlib /usr/X11R6/lib
            ${_OPENGL_LIB_PATH}
    )

    unset(_OPENGL_INCLUDE_PATH)
    unset(_OPENGL_LIB_PATH)

    # On Unix OpenGL most certainly always requires X11.
    # Feel free to tighten up these conditions if you don't
    # think this is always true.
    # It's not true on OSX.

    if (OPENGL_gl_LIBRARY)
      if(NOT X11_FOUND)
        include(${CMAKE_CURRENT_LIST_DIR}/FindX11.cmake)
      endif()
      if (X11_FOUND)
        if (NOT APPLE)
          set (OPENGL_LIBRARIES ${X11_LIBRARIES})
        endif ()
      endif ()
    endif ()

    find_library(OPENGL_glu_LIBRARY
      NAMES GLU MesaGLU
      PATHS ${OPENGL_gl_LIBRARY}
            /opt/graphics/OpenGL/lib
            /usr/openwin/lib
            /usr/shlib /usr/X11R6/lib
    )

  endif()
endif ()

if(OPENGL_gl_LIBRARY)

    if(OPENGL_xmesa_INCLUDE_DIR)
      set( OPENGL_XMESA_FOUND "YES" )
    else()
      set( OPENGL_XMESA_FOUND "NO" )
    endif()

    set( OPENGL_LIBRARIES  ${OPENGL_gl_LIBRARY} ${OPENGL_LIBRARIES})
    if(OPENGL_glu_LIBRARY)
      set( OPENGL_GLU_FOUND "YES" )
      set( OPENGL_LIBRARIES ${OPENGL_glu_LIBRARY} ${OPENGL_LIBRARIES} )
    else()
      set( OPENGL_GLU_FOUND "NO" )
    endif()

    # This deprecated setting is for backward compatibility with CMake1.4
    set (OPENGL_LIBRARY ${OPENGL_LIBRARIES})

endif()

# This deprecated setting is for backward compatibility with CMake1.4
set(OPENGL_INCLUDE_PATH ${OPENGL_INCLUDE_DIR})

# handle the QUIETLY and REQUIRED arguments and set OPENGL_FOUND to TRUE if
# all listed variables are TRUE
include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(OpenGL DEFAULT_MSG OPENGL_gl_LIBRARY)

mark_as_advanced(
  OPENGL_INCLUDE_DIR
  OPENGL_xmesa_INCLUDE_DIR
  OPENGL_glu_LIBRARY
  OPENGL_gl_LIBRARY
)