# Stolen from Braden McDaniel <braden@endoframe.com>
# at http://autoconf-archive.cryp.to/ax_check_gl.html

AC_DEFUN([AX_CHECK_GL],
[AC_REQUIRE([AC_PATH_X])dnl
# AC_REQUIRE([ACX_PTHREAD])dnl

#
# There isn't a reliable way to know we should use the Apple OpenGL framework
# without a configure option.  A Mac OS X user may have installed an
# alternative GL implementation (e.g., Mesa), which may or may not depend on X.
#
AC_ARG_WITH([apple-opengl-framework],
            [AC_HELP_STRING([--with-apple-opengl-framework],
                            [use Apple OpenGL framework (Mac OS X only)])])
if test "X$with_apple_opengl_framework" = "Xyes"; then
  AC_DEFINE([HAVE_APPLE_OPENGL_FRAMEWORK], [1],
            [Use the Apple OpenGL framework.])
  GL_LIBS="-framework OpenGL"
else
  AC_LANG_PUSH(C)

  AX_LANG_COMPILER_MS
  if test X$ax_compiler_ms = Xno; then
    GL_CFLAGS="${PTHREAD_CFLAGS}"
    GL_LIBS="${PTHREAD_LIBS} -lm"
  fi

  #
  # Use x_includes and x_libraries if they have been set (presumably by
  # AC_PATH_X).
  #
  if test "X$no_x" != "Xyes"; then
    if test -n "$x_includes"; then
      GL_CFLAGS="-I${x_includes} ${GL_CFLAGS}"
    fi
    if test -n "$x_libraries"; then
      GL_LIBS="-L${x_libraries} -lX11 ${GL_LIBS}"
    fi
  fi

  AC_CHECK_HEADERS([windows.h])

  AC_CACHE_CHECK([for OpenGL library], [ax_cv_check_gl_libgl],
  [ax_cv_check_gl_libgl="no"
  ax_save_CPPFLAGS="${CPPFLAGS}"
  CPPFLAGS="${GL_CFLAGS} ${CPPFLAGS}"
  ax_save_LIBS="${LIBS}"
  LIBS=""
  ax_check_libs="-lopengl32 -lGL"
  for ax_lib in ${ax_check_libs}; do
    if test X$ax_compiler_ms = Xyes; then
      ax_try_lib=`echo $ax_lib | sed -e 's/^-l//' -e 's/$/.lib/'`
    else
      ax_try_lib="${ax_lib}"
    fi
    LIBS="${ax_try_lib} ${GL_LIBS} ${ax_save_LIBS}"
    AC_LINK_IFELSE(
    [AC_LANG_PROGRAM([[
# if HAVE_WINDOWS_H && defined(_WIN32)
#   include <windows.h>
# endif
# include <GL/gl.h>]],
                     [[glBegin(0)]])],
    [ax_cv_check_gl_libgl="${ax_try_lib}"; break])
  done
  LIBS=${ax_save_LIBS}
  CPPFLAGS=${ax_save_CPPFLAGS}])

  if test "X${ax_cv_check_gl_libgl}" = "Xno"; then
    no_gl="yes"
    GL_CFLAGS=""
    GL_LIBS=""
  else
    GL_LIBS="${ax_cv_check_gl_libgl} ${GL_LIBS}"
  fi
  AC_LANG_POP(C)
fi

AC_SUBST([GL_CFLAGS])
AC_SUBST([GL_LIBS])
])dnl

AC_DEFUN([AX_LANG_COMPILER_MS],
[AC_CACHE_CHECK([whether we are using the Microsoft _AC_LANG compiler],
                [ax_cv_[]_AC_LANG_ABBREV[]_compiler_ms],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[#ifndef _MSC_VER
       choke me
#endif
]])],
                   [ax_compiler_ms=yes],
                   [ax_compiler_ms=no])
ax_cv_[]_AC_LANG_ABBREV[]_compiler_ms=$ax_compiler_ms
])])

AC_DEFUN([AX_CHECK_GLU],
[AC_REQUIRE([AX_CHECK_GL])dnl
AC_REQUIRE([AC_PROG_CXX])dnl
GLU_CFLAGS="${GL_CFLAGS}"
if test "X${with_apple_opengl_framework}" != "Xyes"; then
  AC_CACHE_CHECK([for OpenGL Utility library], [ax_cv_check_glu_libglu],
  [ax_cv_check_glu_libglu="no"
  ax_save_CPPFLAGS="${CPPFLAGS}"
  CPPFLAGS="${GL_CFLAGS} ${CPPFLAGS}"
  ax_save_LIBS="${LIBS}"
  LIBS=""
  ax_check_libs="-lglu32 -lGLU"
  for ax_lib in ${ax_check_libs}; do
    if test X$ax_compiler_ms = Xyes; then
      ax_try_lib=`echo $ax_lib | sed -e 's/^-l//' -e 's/$/.lib/'`
    else
      ax_try_lib="${ax_lib}"
    fi
    LIBS="${ax_try_lib} ${GL_LIBS} ${ax_save_LIBS}"
    #
    # libGLU typically links with libstdc++ on POSIX platforms. However,
    # setting the language to C++ means that test program source is named
    # "conftest.cc"; and Microsoft cl doesn't know what to do with such a
    # file.
    #
    AC_LANG_PUSH([C++])
    if test X$ax_compiler_ms = Xyes; then
      AC_LANG_PUSH([C])
    fi
    AC_LINK_IFELSE(
    [AC_LANG_PROGRAM([[
# if HAVE_WINDOWS_H && defined(_WIN32)
#   include <windows.h>
# endif
# include <GL/glu.h>]],
                     [[gluBeginCurve(0)]])],
    [ax_cv_check_glu_libglu="${ax_try_lib}"; break])
    if test X$ax_compiler_ms = Xyes; then
      AC_LANG_POP([C])
    fi
    AC_LANG_POP([C++])
  done
  LIBS=${ax_save_LIBS}
  CPPFLAGS=${ax_save_CPPFLAGS}])
  if test "X${ax_cv_check_glu_libglu}" = "Xno"; then
    no_glu="yes"
    GLU_CFLAGS=""
    GLU_LIBS=""
  else
    GLU_LIBS="${ax_cv_check_glu_libglu} ${GL_LIBS}"
  fi
fi
AC_SUBST([GLU_CFLAGS])
AC_SUBST([GLU_LIBS])
])

m4_include(wxwin.m4)