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-rw-r--r--Copyright.txt1
-rw-r--r--Help/release/dev/FindOpenGL-glvnd.rst4
-rw-r--r--Modules/FindOpenGL.cmake319
-rw-r--r--Tests/FindOpenGL/CMakeLists.txt7
-rw-r--r--Tests/FindOpenGL/Test/CMakeLists.txt58
5 files changed, 349 insertions, 40 deletions
diff --git a/Copyright.txt b/Copyright.txt
index 978be0a2a9..3c92a815b7 100644
--- a/Copyright.txt
+++ b/Copyright.txt
@@ -76,6 +76,7 @@ The following individuals and institutions are among the Contributors:
* Nicolas Bock <nicolasbock@gmail.com>
* Nicolas Despres <nicolas.despres@gmail.com>
* Nikita Krupen'ko <krnekit@gmail.com>
+* NVIDIA Corporation <www.nvidia.com>
* OpenGamma Ltd. <opengamma.com>
* Per Øyvind Karlsen <peroyvind@mandriva.org>
* Peter Collingbourne <peter@pcc.me.uk>
diff --git a/Help/release/dev/FindOpenGL-glvnd.rst b/Help/release/dev/FindOpenGL-glvnd.rst
new file mode 100644
index 0000000000..b3c8d53818
--- /dev/null
+++ b/Help/release/dev/FindOpenGL-glvnd.rst
@@ -0,0 +1,4 @@
+FindOpenGL-glvnd
+----------------
+
+* The :module:`FindOpenGL` module gained support for GLVND on Linux.
diff --git a/Modules/FindOpenGL.cmake b/Modules/FindOpenGL.cmake
index af83fb735c..59bee41aa8 100644
--- a/Modules/FindOpenGL.cmake
+++ b/Modules/FindOpenGL.cmake
@@ -7,15 +7,28 @@
#
# FindModule for OpenGL and GLU.
#
+# Optional COMPONENTS
+# ^^^^^^^^^^^^^^^^^^^
+#
+# This module respects several optional COMPONENTS: ``EGL``, ``GLX``, and
+# ``OpenGL``. There are corresponding import targets for each of these flags.
+#
# IMPORTED Targets
# ^^^^^^^^^^^^^^^^
#
# This module defines the :prop_tgt:`IMPORTED` targets:
#
# ``OpenGL::GL``
-# Defined if the system has OpenGL.
+# Defined to the platform-specific OpenGL libraries if the system has OpenGL.
+# ``OpenGL::OpenGL``
+# Defined to libOpenGL if the system is GLVND-based.
+# ``OpenGL::GL``
# ``OpenGL::GLU``
# Defined if the system has GLU.
+# ``OpenGL::GLX``
+# Defined if the system has GLX.
+# ``OpenGL::EGL``
+# Defined if the system has EGL.
#
# Result Variables
# ^^^^^^^^^^^^^^^^
@@ -23,40 +36,87 @@
# This module sets the following variables:
#
# ``OPENGL_FOUND``
-# True, if the system has OpenGL.
+# True, if the system has OpenGL and all components are found.
# ``OPENGL_XMESA_FOUND``
# True, if the system has XMESA.
# ``OPENGL_GLU_FOUND``
# True, if the system has GLU.
+# ``OpenGL_OpenGL_FOUND``
+# True, if the system has an OpenGL library.
+# ``OpenGL_GLX_FOUND``
+# True, if the system has GLX.
+# ``OpenGL_EGL_FOUND``
+# True, if the system has EGL.
# ``OPENGL_INCLUDE_DIR``
# Path to the OpenGL include directory.
+# ``OPENGL_EGL_INCLUDE_DIRS``
+# Path to the EGL include directory.
# ``OPENGL_LIBRARIES``
-# Paths to the OpenGL and GLU libraries.
+# Paths to the OpenGL library, windowing system libraries, and GLU libraries.
+# On Linux, this assumes glX and is never correct for EGL-based targets.
+# Clients are encouraged to use the ``OpenGL::*`` import targets instead.
#
-# If you want to use just GL you can use these values:
+# Cache variables
+# ^^^^^^^^^^^^^^^
#
-# ``OPENGL_gl_LIBRARY``
-# Path to the OpenGL library.
+# The following cache variables may also be set:
+#
+# ``OPENGL_egl_LIBRARY``
+# Path to the EGL library.
# ``OPENGL_glu_LIBRARY``
# Path to the GLU library.
+# ``OPENGL_glx_LIBRARY``
+# Path to the GLVND 'GLX' library.
+# ``OPENGL_opengl_LIBRARY``
+# Path to the GLVND 'OpenGL' library
+# ``OPENGL_gl_LIBRARY``
+# Path to the OpenGL library. New code should prefer the ``OpenGL::*`` import
+# targets.
+#
+# Linux-specific
+# ^^^^^^^^^^^^^^
#
-# OSX Specific
-# ^^^^^^^^^^^^
+# Some Linux systems utilize GLVND as a new ABI for OpenGL. GLVND separates
+# context libraries from OpenGL itself; OpenGL lives in "libOpenGL", and
+# contexts are defined in "libGLX" or "libEGL". GLVND is currently the only way
+# to get OpenGL 3+ functionality via EGL in a manner portable across vendors.
#
-# On OSX default to using the framework version of OpenGL. People will
-# have to change the cache values of OPENGL_glu_LIBRARY and
+# On Linux systems FindOpenGL defaults to using GLVND if available. Users can
+# utilize GLVND explicitly with targets ``OpenGL::OpenGL``, ``OpenGL::GLX``, and
+# ``OpenGL::EGL``. Additionally, when GLVND is available the ``OpenGL::GL``
+# target is equivalent to ``OpenGL::OpenGL OpenGL::GLX``. When the system is
+# not GLVND-based, ``OpenGL::GL`` expands to libGL as it has historically done.
+# Thus, for non-EGL-based Linux targets, the ``OpenGL::GL`` target is most
+# portable.
+#
+# For EGL targets the client must rely on GLVND support on the user's system.
+# Linking should use the ``OpenGL::OpenGL OpenGL::EGL`` targets. Using GLES*
+# libraries is theoretically possible in place of ``OpenGL::OpenGL``, but this
+# module does not currently support that; contributions welcome.
+#
+# ``OPENGL_egl_LIBRARY`` and ``OPENGL_EGL_INCLUDE_DIRS`` are defined in the case of
+# GLVND. For non-GLVND Linux and other systems these are left undefined.
+#
+# macOS-Specific
+# ^^^^^^^^^^^^^^
+#
+# On OSX FindOpenGL defaults 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.
-
set(_OpenGL_REQUIRED_VARS OPENGL_gl_LIBRARY)
-if (CYGWIN)
+# Provide OPENGL_USE_<C> variables for each component.
+foreach(component ${OpenGL_FIND_COMPONENTS})
+ string(TOUPPER ${component} _COMPONENT)
+ set(OPENGL_USE_${_COMPONENT} 1)
+endforeach()
+if (CYGWIN)
find_path(OPENGL_INCLUDE_DIR GL/gl.h )
list(APPEND _OpenGL_REQUIRED_VARS OPENGL_INCLUDE_DIR)
find_library(OPENGL_gl_LIBRARY opengl32 )
-
find_library(OPENGL_glu_LIBRARY glu32 )
elseif (WIN32)
@@ -70,7 +130,6 @@ elseif (WIN32)
endif()
elseif (APPLE)
-
# The OpenGL.framework provides both gl and glu
find_library(OPENGL_gl_LIBRARY OpenGL DOC "OpenGL library for OS X")
find_library(OPENGL_glu_LIBRARY OpenGL DOC
@@ -104,15 +163,14 @@ else()
# 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}
)
- list(APPEND _OpenGL_REQUIRED_VARS OPENGL_INCLUDE_DIR)
-
+ find_path(OPENGL_GLX_INCLUDE_DIR GL/glx.h ${_OPENGL_INCLUDE_PATH})
+ find_path(OPENGL_EGL_INCLUDE_DIR EGL/egl.h ${_OPENGL_INCLUDE_PATH})
find_path(OPENGL_xmesa_INCLUDE_DIR GL/xmesa.h
/usr/share/doc/NVIDIA_GLX-1.0/include
/usr/openwin/share/include
@@ -126,6 +184,90 @@ else()
/usr/shlib /usr/X11R6/lib
${_OPENGL_LIB_PATH}
)
+ # Search for the GLVND libraries. We do this regardless of COMPONENTS; we'll
+ # take into account the COMPONENTS logic later.
+ find_library(OPENGL_opengl_LIBRARY
+ NAMES OpenGL
+ PATHS /usr/X11R6/lib
+ ${_OPENGL_LIB_PATH}
+ )
+
+ find_library(OPENGL_glx_LIBRARY
+ NAMES GLX
+ PATHS /usr/X11R6/lib
+ ${_OPENGL_LIB_PATH}
+ )
+
+ find_library(OPENGL_egl_LIBRARY
+ NAMES EGL
+ PATHS ${_OPENGL_LIB_PATH}
+ )
+
+ find_library(OPENGL_glu_LIBRARY
+ NAMES GLU MesaGLU
+ PATHS ${OPENGL_gl_LIBRARY}
+ /opt/graphics/OpenGL/lib
+ /usr/openwin/lib
+ /usr/shlib /usr/X11R6/lib
+ )
+
+ # FPHSA cannot handle "this OR that is required", so we conditionally set what
+ # it must look for. First clear any previous config we might have done:
+ set(_OpenGL_REQUIRED_VARS)
+
+ # now we append the libraries as appropriate. The complicated logic
+ # basically comes down to "use libOpenGL when we can, and add in specific
+ # context mechanisms when requested, or we need them to preserve the previous
+ # default where glx is always available."
+ if((NOT OPENGL_USE_EGL AND
+ NOT OPENGL_opengl_LIBRARY AND
+ OPENGL_glx_LIBRARY AND
+ NOT OPENGL_gl_LIBRARY) OR
+ (NOT OPENGL_USE_EGL AND
+ NOT OPENGL_glx_LIBRARY AND
+ NOT OPENGL_gl_LIBRARY) OR
+ (NOT OPENGL_USE_EGL AND
+ OPENGL_opengl_LIBRARY AND
+ OPENGL_glx_LIBRARY) OR
+ ( OPENGL_USE_EGL))
+ list(APPEND _OpenGL_REQUIRED_VARS OPENGL_opengl_LIBRARY)
+ endif()
+
+ # GLVND GLX library. Preferred when available.
+ if((NOT OPENGL_USE_OPENGL AND
+ NOT OPENGL_USE_GLX AND
+ NOT OPENGL_USE_EGL AND
+ NOT OPENGL_glx_LIBRARY AND
+ NOT OPENGL_gl_LIBRARY) OR
+ ( OPENGL_USE_GLX AND
+ NOT OPENGL_USE_EGL AND
+ NOT OPENGL_glx_LIBRARY AND
+ NOT OPENGL_gl_LIBRARY) OR
+ (NOT OPENGL_USE_EGL AND
+ OPENGL_opengl_LIBRARY AND
+ OPENGL_glx_LIBRARY) OR
+ (OPENGL_USE_GLX AND OPENGL_USE_EGL))
+ list(APPEND _OpenGL_REQUIRED_VARS OPENGL_glx_LIBRARY)
+ endif()
+
+ # GLVND EGL library.
+ if(OPENGL_USE_EGL)
+ list(APPEND _OpenGL_REQUIRED_VARS OPENGL_egl_LIBRARY)
+ endif()
+
+ # Old-style "libGL" library: used as a fallback when GLVND isn't available.
+ if((NOT OPENGL_USE_EGL AND
+ NOT OPENGL_opengl_LIBRARY AND
+ OPENGL_glx_LIBRARY AND
+ OPENGL_gl_LIBRARY) OR
+ (NOT OPENGL_USE_EGL AND
+ NOT OPENGL_glx_LIBRARY AND
+ OPENGL_gl_LIBRARY))
+ list(APPEND _OpenGL_REQUIRED_VARS OPENGL_gl_LIBRARY)
+ endif()
+
+ # We always need the 'gl.h' include dir.
+ list(APPEND _OpenGL_REQUIRED_VARS OPENGL_INCLUDE_DIR)
unset(_OPENGL_INCLUDE_PATH)
unset(_OPENGL_LIB_PATH)
@@ -137,42 +279,99 @@ else()
/usr/openwin/lib
/usr/shlib /usr/X11R6/lib
)
-
endif ()
-if(OPENGL_gl_LIBRARY)
+if(OPENGL_xmesa_INCLUDE_DIR)
+ set( OPENGL_XMESA_FOUND "YES" )
+else()
+ set( OPENGL_XMESA_FOUND "NO" )
+endif()
- if(OPENGL_xmesa_INCLUDE_DIR)
- set( OPENGL_XMESA_FOUND "YES" )
- else()
- set( OPENGL_XMESA_FOUND "NO" )
- endif()
+if(OPENGL_glu_LIBRARY)
+ set( OPENGL_GLU_FOUND "YES" )
+else()
+ set( OPENGL_GLU_FOUND "NO" )
+endif()
- set( OPENGL_LIBRARIES ${OPENGL_gl_LIBRARY} ${OPENGL_LIBRARIES})
- if(OPENGL_glu_LIBRARY)
- set( OPENGL_GLU_FOUND "YES" )
- if(NOT "${OPENGL_glu_LIBRARY}" STREQUAL "${OPENGL_gl_LIBRARY}")
- set( OPENGL_LIBRARIES ${OPENGL_glu_LIBRARY} ${OPENGL_LIBRARIES} )
- endif()
- else()
- set( OPENGL_GLU_FOUND "NO" )
- endif()
+# OpenGL_OpenGL_FOUND is a bit unique in that it is okay if /either/ libOpenGL
+# or libGL is found.
+# Using libGL with libEGL is never okay, though; we handle that case later.
+if(NOT OPENGL_opengl_LIBRARY AND NOT OPENGL_gl_LIBRARY)
+ set(OpenGL_OpenGL_FOUND FALSE)
+else()
+ set(OpenGL_OpenGL_FOUND TRUE)
+endif()
- # This deprecated setting is for backward compatibility with CMake1.4
- set (OPENGL_LIBRARY ${OPENGL_LIBRARIES})
+if(OPENGL_glx_LIBRARY AND OPENGL_GLX_INCLUDE_DIR)
+ set(OpenGL_GLX_FOUND TRUE)
+else()
+ set(OpenGL_GLX_FOUND FALSE)
+endif()
+if(OPENGL_egl_LIBRARY AND OPENGL_EGL_INCLUDE_DIR)
+ set(OpenGL_EGL_FOUND TRUE)
+else()
+ set(OpenGL_EGL_FOUND FALSE)
endif()
-# This deprecated setting is for backward compatibility with CMake1.4
-set(OPENGL_INCLUDE_PATH ${OPENGL_INCLUDE_DIR})
+# User-visible names should be plural.
+if(OPENGL_EGL_INCLUDE_DIR)
+ set(OPENGL_EGL_INCLUDE_DIRS ${OPENGL_EGL_INCLUDE_DIR})
+endif()
include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
-FIND_PACKAGE_HANDLE_STANDARD_ARGS(OpenGL REQUIRED_VARS ${_OpenGL_REQUIRED_VARS})
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(OpenGL REQUIRED_VARS ${_OpenGL_REQUIRED_VARS}
+ HANDLE_COMPONENTS)
unset(_OpenGL_REQUIRED_VARS)
# OpenGL:: targets
if(OPENGL_FOUND)
- if(NOT TARGET OpenGL::GL)
+ # ::OpenGL is a GLVND library, and thus Linux-only: we don't bother checking
+ # for a framework version of this library.
+ if(OPENGL_opengl_LIBRARY AND NOT TARGET OpenGL::OpenGL)
+ if(IS_ABSOLUTE "${OPENGL_opengl_LIBRARY}")
+ add_library(OpenGL::OpenGL UNKNOWN IMPORTED)
+ set_target_properties(OpenGL::OpenGL PROPERTIES IMPORTED_LOCATION
+ "${OPENGL_opengl_LIBRARY}")
+ else()
+ add_library(OpenGL::OpenGL INTERFACE IMPORTED)
+ set_target_properties(OpenGL::OpenGL PROPERTIES IMPORTED_LIBNAME
+ "${OPENGL_opengl_LIBRARY}")
+ endif()
+ set_target_properties(OpenGL::OpenGL PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
+ "${OPENGL_INCLUDE_DIR}")
+ endif()
+
+ # ::GLX is a GLVND library, and thus Linux-only: we don't bother checking
+ # for a framework version of this library.
+ if(OpenGL_GLX_FOUND AND NOT TARGET OpenGL::GLX)
+ if(IS_ABSOLUTE "${OPENGL_glx_LIBRARY}")
+ add_library(OpenGL::GLX UNKNOWN IMPORTED)
+ set_target_properties(OpenGL::GLX PROPERTIES IMPORTED_LOCATION
+ "${OPENGL_glx_LIBRARY}")
+ else()
+ add_library(OpenGL::GLX INTERFACE IMPORTED)
+ set_target_properties(OpenGL::GLX PROPERTIES IMPORTED_LIBNAME
+ "${OPENGL_glx_LIBRARY}")
+ endif()
+ set_target_properties(OpenGL::GLX PROPERTIES INTERFACE_LINK_LIBRARIES
+ OpenGL::OpenGL)
+ set_target_properties(OpenGL::GLX PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
+ "${OPENGL_GLX_INCLUDE_DIR}")
+ endif()
+
+ if(TARGET OpenGL::OpenGL AND TARGET OpenGL::GLX AND NOT TARGET OpenGL::GL)
+ # if GLVND with GLX is available, make ::GL a synonym for 'OpenGL::OpenGL
+ # OpenGL::GLX'.
+ add_library(OpenGL::GL INTERFACE IMPORTED)
+ set_target_properties(OpenGL::GL PROPERTIES INTERFACE_LINK_LIBRARIES
+ OpenGL::OpenGL)
+ set_property(TARGET OpenGL::GL APPEND PROPERTY INTERFACE_LINK_LIBRARIES
+ OpenGL::GLX)
+ set_target_properties(OpenGL::GL PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
+ "${OPENGL_INCLUDE_DIR}")
+
+ elseif(NOT TARGET OpenGL::GL)
if(IS_ABSOLUTE "${OPENGL_gl_LIBRARY}")
add_library(OpenGL::GL UNKNOWN IMPORTED)
if(OPENGL_gl_LIBRARY MATCHES "/([^/]+)\\.framework$")
@@ -195,6 +394,28 @@ if(OPENGL_FOUND)
INTERFACE_INCLUDE_DIRECTORIES "${OPENGL_INCLUDE_DIR}")
endif()
+ # ::EGL is a GLVND library, and thus Linux-only: we don't bother checking
+ # for a framework version of this library.
+ # Note we test for OpenGL::OpenGL as a target. When this module is updated to
+ # support GLES, we would additionally want to check for the hypothetical GLES
+ # target and enable EGL if either ::GLES or ::OpenGL is created.
+ if(TARGET OpenGL::OpenGL AND OpenGL_EGL_FOUND AND NOT TARGET OpenGL::EGL)
+ if(IS_ABSOLUTE "${OPENGL_egl_LIBRARY}")
+ add_library(OpenGL::EGL UNKNOWN IMPORTED)
+ set_target_properties(OpenGL::EGL PROPERTIES IMPORTED_LOCATION
+ "${OPENGL_egl_LIBRARY}")
+ else()
+ add_library(OpenGL::EGL INTERFACE IMPORTED)
+ set_target_properties(OpenGL::EGL PROPERTIES IMPORTED_LIBNAME
+ "${OPENGL_egl_LIBRARY}")
+ endif()
+ set_target_properties(OpenGL::EGL PROPERTIES INTERFACE_LINK_LIBRARIES
+ OpenGL::OpenGL)
+ # Note that EGL's include directory is different from OpenGL/GLX's!
+ set_target_properties(OpenGL::EGL PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
+ "${OPENGL_EGL_INCLUDE_DIR}")
+ endif()
+
if(OPENGL_GLU_FOUND AND NOT TARGET OpenGL::GLU)
if(IS_ABSOLUTE "${OPENGL_glu_LIBRARY}")
add_library(OpenGL::GLU UNKNOWN IMPORTED)
@@ -217,11 +438,31 @@ if(OPENGL_FOUND)
set_target_properties(OpenGL::GLU PROPERTIES
INTERFACE_LINK_LIBRARIES OpenGL::GL)
endif()
+
+ # OPENGL_LIBRARIES mirrors OpenGL::GL's logic ...
+ set(OPENGL_LIBRARIES ${OPENGL_gl_LIBRARY})
+ if(TARGET OpenGL::GLX AND TARGET OpenGL::OpenGL)
+ set(OPENGL_LIBRARIES ${OPENGL_opengl_LIBRARY} ${OPENGL_glx_LIBRARY})
+ endif()
+ # ... and also includes GLU, if available.
+ if(TARGET OpenGL::GLU)
+ list(APPEND OPENGL_LIBRARIES ${OPENGL_glu_LIBRARY})
+ endif()
endif()
+# This deprecated setting is for backward compatibility with CMake1.4
+set(OPENGL_LIBRARY ${OPENGL_LIBRARIES})
+# This deprecated setting is for backward compatibility with CMake1.4
+set(OPENGL_INCLUDE_PATH ${OPENGL_INCLUDE_DIR})
+
mark_as_advanced(
OPENGL_INCLUDE_DIR
OPENGL_xmesa_INCLUDE_DIR
+ OPENGL_egl_LIBRARY
OPENGL_glu_LIBRARY
+ OPENGL_glx_LIBRARY
OPENGL_gl_LIBRARY
+ OPENGL_opengl_LIBRARY
+ OPENGL_EGL_INCLUDE_DIR
+ OPENGL_GLX_INCLUDE_DIR
)
diff --git a/Tests/FindOpenGL/CMakeLists.txt b/Tests/FindOpenGL/CMakeLists.txt
index 9aa3abafb1..97c9e60529 100644
--- a/Tests/FindOpenGL/CMakeLists.txt
+++ b/Tests/FindOpenGL/CMakeLists.txt
@@ -1,3 +1,9 @@
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux" AND CMake_TEST_FindOpenGL_VND)
+ set(_vnd_testing TRUE)
+else()
+ set(_vnd_testing FALSE)
+endif()
+
add_test(NAME FindOpenGL.Test COMMAND
${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
--build-and-test
@@ -6,5 +12,6 @@ add_test(NAME FindOpenGL.Test COMMAND
${build_generator_args}
--build-project TestFindOpenGL
--build-options ${build_options}
+ -DOpenGL_TEST_VND=${_vnd_testing}
--test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
)
diff --git a/Tests/FindOpenGL/Test/CMakeLists.txt b/Tests/FindOpenGL/Test/CMakeLists.txt
index cac3424889..3b5ffeecd4 100644
--- a/Tests/FindOpenGL/Test/CMakeLists.txt
+++ b/Tests/FindOpenGL/Test/CMakeLists.txt
@@ -1,14 +1,70 @@
-cmake_minimum_required(VERSION 3.7)
+cmake_minimum_required(VERSION 3.9)
project(TestFindOpenGL C)
include(CTest)
find_package(OpenGL REQUIRED)
+# import target for GLU
add_executable(test_tgt main.c)
target_link_libraries(test_tgt OpenGL::GLU)
add_test(NAME test_tgt COMMAND test_tgt)
+# OPENGL_LIBRARIES should be whatever libraries are needed to link.
add_executable(test_var main.c)
target_include_directories(test_var PRIVATE ${OPENGL_INGLUDE_DIRS})
target_link_libraries(test_var PRIVATE ${OPENGL_LIBRARIES})
add_test(NAME test_var COMMAND test_var)
+
+# VND support adds an ::OpenGL import target. This can be used for OpenGL-only
+# code (code that does not manipulate contexts, like our 'main.c'). Without
+# VND, ::GL can be used for both context and non-context OpenGL code.
+if(OpenGL_TEST_VND)
+ add_executable(test_comp_none main.c)
+ target_link_libraries(test_comp_none PRIVATE OpenGL::OpenGL)
+ add_test(NAME test_comp_none COMMAND test_comp_none)
+else()
+ add_executable(test_comp_none main.c)
+ target_link_libraries(test_comp_none PRIVATE OpenGL::GL)
+ add_test(NAME test_comp_none COMMAND test_comp_none)
+endif()
+
+# GLX
+if(OpenGL_TEST_VND)
+ find_package(OpenGL REQUIRED COMPONENTS OpenGL GLX)
+ add_executable(test_comp_glx main.c)
+ target_link_libraries(test_comp_glx PRIVATE OpenGL::OpenGL OpenGL::GLX)
+ add_test(NAME test_comp_glx COMMAND test_comp_glx)
+else()
+ # non-VND systems won't have it, but an optional search for GLX should still
+ # be okay.
+ find_package(OpenGL COMPONENTS GLX)
+ add_executable(test_comp_glx_novnd main.c)
+ target_link_libraries(test_comp_glx_novnd PRIVATE OpenGL::GL)
+ add_test(NAME test_comp_glx_novnd COMMAND test_comp_glx_novnd)
+endif()
+
+# EGL is only available on Linux+GLVND at present.
+if(OpenGL_TEST_VND)
+ find_package(OpenGL COMPONENTS OpenGL EGL)
+ if(OpenGL_EGL_FOUND)
+ add_executable(test_comp_egl main.c)
+ target_link_libraries(test_comp_egl PRIVATE OpenGL::OpenGL OpenGL::EGL)
+ add_test(NAME test_comp_egl COMMAND test_comp_egl)
+ # EGL-only code should not link to GLX.
+ execute_process(COMMAND ldd test_comp_egl
+ OUTPUT_VARIABLE LDD_OUT
+ ERROR_VARIABLE LDD_ERR)
+ if("${LDD_OUT}" MATCHES "GLX")
+ message(FATAL_ERROR "EGL-only code links to GLX!")
+ endif()
+ endif()
+
+ # all three COMPONENTS together.
+ find_package(OpenGL COMPONENTS OpenGL EGL GLX)
+ if(OpenGL_EGL_FOUND AND OpenGL_GLX_FOUND)
+ add_executable(test_comp_both main.c)
+ target_link_libraries(test_comp_both PRIVATE OpenGL::OpenGL OpenGL::EGL
+ OpenGL::GLX)
+ add_test(NAME test_comp_both COMMAND test_comp_both)
+ endif()
+endif()