dnl  Copyright (C) 2003  OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
dnl  CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS 
dnl 
dnl  This library is free software; you can redistribute it and/or 
dnl  modify it under the terms of the GNU Lesser General Public 
dnl  License as published by the Free Software Foundation; either 
dnl  version 2.1 of the License. 
dnl 
dnl  This library is distributed in the hope that it will be useful, 
dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of 
dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
dnl  Lesser General Public License for more details. 
dnl 
dnl  You should have received a copy of the GNU Lesser General Public 
dnl  License along with this library; if not, write to the Free Software 
dnl  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA 
dnl 
dnl  See http://www.opencascade.org/SALOME/ or email : webmaster.salome@opencascade.org 
dnl
dnl
dnl
AC_DEFUN([CHECK_OPENGL],[
AC_REQUIRE([AC_PROG_CC])dnl
AC_REQUIRE([AC_PROG_CPP])dnl
AC_REQUIRE([AC_LINKER_OPTIONS])dnl

AC_LANG_SAVE
AC_LANG_CPLUSPLUS

AC_ARG_WITH(opengl,
  [AC_HELP_STRING([--with-opengl=DIR],[root directory path of OpenGL installation])],
  [opengl_dir="$withval"], 
  [dirs="/usr/lib${LIB_LOCATION_SUFFIX} /usr/local/lib${LIB_LOCATION_SUFFIX} /opt/graphics/OpenGL/lib${LIB_LOCATION_SUFFIX} /usr/openwin/lib${LIB_LOCATION_SUFFIX} /usr/X11R6/lib${LIB_LOCATION_SUFFIX}"])dnl

AC_CHECKING(for OpenGL)
AC_CHECKING(for OpenGL headers)

OGL_INCLUDES=""
OGL_LIBS=""

GL_LIB_PATH=""
GLU_LIB_PATH=""

OpenGL_ok=no
OpenGL_libs_ok=no
OpenGL_headers_ok=no

dnl openGL headers
# by default
if test "x${opengl_dir}" != "x" ; then
  AC_MSG_RESULT(for opengl_dir: $opengl_dir)
  AC_CHECK_HEADER([${opengl_dir}/include/GL/gl.h],
                  [OpenGL_headers_ok=yes; OGL_INCLUDES="-I${opengl_dir}/include"],
                  [OpenGL_headers_ok=no])
  if test "x${OpenGL_headers_ok}" = "xyes" ; then
    AC_CHECKING(for default OpenGL library)
    if test "x${opengl_dir}" = "x/usr" ; then
      OGL_LIBS=""
    else
      OGL_LIBS="-L${opengl_dir}/lib"
    fi
    LDFLAGS_old="$LDFLAGS"
    LDFLAGS="$LDFLAGS $OGL_LIBS"
    AC_CHECK_LIB([GL],
                 [glBegin],
                 [OpenGL_libs_ok=yes],
                 [OpenGL_libs_ok=no])
    if test "x${OpenGL_libs_ok}" = "xyes" ; then
      AC_TRY_LINK([],
                  [],
                  [OpenGL_libs_ok=yes ; OpenGL_ok=yes; OGL_LIBS="$OGL_LIBS -lGL"],
                  [OpenGL_libs_ok=no])
    fi
    LDFLAGS="$LDFLAGS_old"
  fi
fi

if test "x${OpenGL_headers_ok}" = "xno" ; then
  AC_CHECK_HEADER(GL/gl.h,
                  [OpenGL_headers_ok=yes],
                  [OpenGL_headers_ok=no])
fi

# under SunOS ?
if test "x${OpenGL_headers_ok}" = "xno" ; then
  AC_CHECK_HEADERS(/usr/openwin/share/include/GL/glxmd.h,
                  [OpenGL_headers_ok=yes; OGL_INCLUDES="-I/usr/openwin/share/include/"],
                  [OpenGL_headers_ok=no])
fi

# under IRIX ?
if test "x${OpenGL_headers_ok}" = "xno" ; then
  AC_CHECK_HEADERS(/opt/graphics/OpenGL/include/GL/glxmd.h,
                  [OpenGL_headers_ok=yes; OGL_INCLUDES="-I/opt/graphics/OpenGL/include"],
                  [OpenGL_headers_ok=no])
fi

# some linux OpenGL servers hide the includes in /usr/X11R6/include/GL
if test "x${OpenGL_headers_ok}" = "xno" ; then
  AC_CHECK_HEADERS(/usr/X11R6/include/GL/gl.h,
                  [OpenGL_headers_ok=yes; OGL_INCLUDES="-I/usr/X11R6/include"],
                  [OpenGL_headers_ok=no])
fi

if test "x${OpenGL_headers_ok}" = "xyes" ; then
  AC_CHECKING(for OpenGL library)
  for idir in $dirs; do
    if test -r "${idir}/libGL.so"; then
      AC_MSG_RESULT(in ${idir})
      if test "x${idir}" = "x/usr/lib${LIB_LOCATION_SUFFIX}" ; then
        GL_LIB_PATH=""
      else
        GL_LIB_PATH="-L${idir}"
      fi
      break
    fi
    # under IRIX ?
    if test -r "${idir}/libGL.sl"; then
      AC_MSG_RESULT(in ${idir})
      if test "x${idir}" = "x/usr/lib${LIB_LOCATION_SUFFIX}" ; then
        GL_LIB_PATH=""
      else
        GL_LIB_PATH="-L${idir}"
      fi
      break
    fi
  done
  LDFLAGS_old="${LDFLAGS}"
  LDFLAGS="${LDFLAGS} ${GL_LIB_PATH}"
  AC_CHECK_LIB([GL],
               [glBegin],
               [OpenGL_libs_ok=yes],
               [OpenGL_libs_ok=no])
  if test "x${OpenGL_libs_ok}" = "xyes" ; then
    AC_TRY_LINK([],
                [],
                [OpenGL_libs_ok=yes ; OGL_LIBS="${OGL_LIBS} ${GL_LIB_PATH} -lGL"],
                [OpenGL_libs_ok=no])
  fi
  LDFLAGS="$LDFLAGS_old"
fi

if test "x${OpenGL_libs_ok}" = "xyes" ; then
  for idir in $dirs; do
    if test -r "${idir}/libGLU.so"; then
      AC_MSG_RESULT(in ${idir})
      if test "x${idir}" = "x/usr/lib${LIB_LOCATION_SUFFIX}" ; then
        GLU_LIB_PATH=""
      else
        GLU_LIB_PATH="-L${idir}"
      fi
      break
    fi
    # under IRIX ?
    if test -r "${idir}/libGLU.sl"; then
      AC_MSG_RESULT(in ${idir})
      if test "x${idir}" = "x/usr/lib${LIB_LOCATION_SUFFIX}" ; then
        GLU_LIB_PATH=""
      else
        GLU_LIB_PATH="-L${idir}"
      fi
      break
    fi
  done
  LDFLAGS_old="${LDFLAGS}"
  LDFLAGS="${LDFLAGS} ${OGL_LIBS} ${GLU_LIB_PATH}"
  AC_CHECK_LIB([GLU],
               [gluBeginSurface],
               [OpenGL_libs_ok=yes],
               [OpenGL_libs_ok=no])
  if test "x${OpenGL_libs_ok}" = "xyes" ; then
    AC_TRY_LINK([],
                [],
                [OpenGL_libs_ok=yes ; OGL_LIBS="${OGL_LIBS} ${GLU_LIB_PATH} -lGLU"],
                [OpenGL_libs_ok=no])
  fi
  LDFLAGS="$LDFLAGS_old"
fi

if test "x${OpenGL_headers_ok}" = "xyes" ; then
  if test "x${OpenGL_libs_ok}" = "xyes" ; then
    OpenGL_ok=yes
  fi
fi

AC_MSG_RESULT(for OpenGL_headers_ok: $OpenGL_headers_ok)
AC_MSG_RESULT(for OpenGL_libs_ok: $OpenGL_libs_ok)
AC_MSG_RESULT(for OpenGL_ok: $OpenGL_ok)

AC_SUBST(OGL_INCLUDES)
AC_SUBST(OGL_LIBS)

AC_LANG_RESTORE

])dnl