From e2e8a690cd7d1e5eba574b810842296beb603d9c Mon Sep 17 00:00:00 2001 From: Tom Fogal Date: Thu, 8 Jun 2017 18:02:42 -0700 Subject: FindOpenGL: Add support for GLVND on Linux Find GLVND components if available. Add `GLX` and `EGL` options for COMPONENTS that allow requesting these libraries explicitly. Introduce new import targets for these windowing-system-specific libraries. On a GLVND system, populate the legacy `OPENGL_LIBRARIES` variable and the `OpenGL::GL` target using the `OpenGL` and `GLX` components. On non-GLVND systems, continue to use the legacy `GL` library and simply do not provide the GLVND components. Application code can choose to adapt based on the availability of GLVND components as imported targets. --- Copyright.txt | 1 + Help/release/dev/FindOpenGL-glvnd.rst | 4 + Modules/FindOpenGL.cmake | 319 +++++++++++++++++++++++++++++----- Tests/FindOpenGL/CMakeLists.txt | 7 + Tests/FindOpenGL/Test/CMakeLists.txt | 58 ++++++- 5 files changed, 349 insertions(+), 40 deletions(-) create mode 100644 Help/release/dev/FindOpenGL-glvnd.rst 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 * Nicolas Despres * Nikita Krupen'ko +* NVIDIA Corporation * OpenGamma Ltd. * Per Øyvind Karlsen * Peter Collingbourne 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_ 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 - 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 $ --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 $ ) 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() -- cgit v1.2.1