From 0503225928cad4c6590ee06cc8c863ab71bdd000 Mon Sep 17 00:00:00 2001
From: Prateek Machiraju <prateek.machiraju@gmail.com>
Date: Sun, 20 Sep 2020 12:31:20 -0400
Subject: [PATCH] [build] CMake: Fix Metal linking on macOS (#2725)

---
 cmake/modules/LinkMacOSGUI.cmake     | 5 +++++
 cscore/CMakeLists.txt                | 6 ++++++
 simulation/halsim_gui/CMakeLists.txt | 3 +++
 wpigui/CMakeLists.txt                | 2 ++
 4 files changed, 16 insertions(+)
 create mode 100644 cmake/modules/LinkMacOSGUI.cmake

diff --git a/cmake/modules/LinkMacOSGUI.cmake b/cmake/modules/LinkMacOSGUI.cmake
new file mode 100644
index 0000000000..f76554eee8
--- /dev/null
+++ b/cmake/modules/LinkMacOSGUI.cmake
@@ -0,0 +1,5 @@
+macro(wpilib_link_macos_gui target)
+    if (APPLE)
+        set_target_properties(${target} PROPERTIES LINK_FLAGS "-framework Metal -framework QuartzCore")
+    endif()
+endmacro()
diff --git a/cscore/CMakeLists.txt b/cscore/CMakeLists.txt
index 92bef994b9..aee280f087 100644
--- a/cscore/CMakeLists.txt
+++ b/cscore/CMakeLists.txt
@@ -3,6 +3,7 @@ project(cscore)
 include(SubDirList)
 include(CompileWarnings)
 include(AddTest)
+include(LinkMacOSGUI)
 
 find_package( OpenCV REQUIRED )
 
@@ -63,6 +64,11 @@ foreach(example ${cscore_examples})
     if(cscore_example_src)
         add_executable(cscore_${example} ${cscore_example_src})
         wpilib_target_warnings(cscore_${example})
+
+        if (${example} STREQUAL "usbviewer")
+            wpilib_link_macos_gui(cscore_${example})
+        endif()
+
         target_link_libraries(cscore_${example} cscore ${add_libs})
         set_property(TARGET cscore_${example} PROPERTY FOLDER "examples")
     endif()
diff --git a/simulation/halsim_gui/CMakeLists.txt b/simulation/halsim_gui/CMakeLists.txt
index 5d821269b2..424ff5bdc7 100644
--- a/simulation/halsim_gui/CMakeLists.txt
+++ b/simulation/halsim_gui/CMakeLists.txt
@@ -1,12 +1,15 @@
 project(halsim_gui)
 
 include(CompileWarnings)
+include(LinkMacOSGUI)
 
 file(GLOB halsim_gui_src src/main/native/cpp/*.cpp)
 
 add_library(halsim_gui MODULE ${halsim_gui_src})
 wpilib_target_warnings(halsim_gui)
 set_target_properties(halsim_gui PROPERTIES DEBUG_POSTFIX "d")
+
+wpilib_link_macos_gui(halsim_gui)
 target_link_libraries(halsim_gui PUBLIC hal ntcore wpimath PRIVATE wpigui)
 
 target_include_directories(halsim_gui PRIVATE src/main/native/include)
diff --git a/wpigui/CMakeLists.txt b/wpigui/CMakeLists.txt
index 9b58161c49..7816338a1e 100644
--- a/wpigui/CMakeLists.txt
+++ b/wpigui/CMakeLists.txt
@@ -1,6 +1,7 @@
 project(wpigui)
 
 include(CompileWarnings)
+include(LinkMacOSGUI)
 
 file(GLOB wpigui_src src/main/native/cpp/*.cpp)
 file(GLOB wpigui_windows_src src/main/native/directx11/*.cpp)
@@ -33,6 +34,7 @@ else()
 endif()
 
 add_executable(wpiguidev src/dev/native/cpp/main.cpp)
+wpilib_link_macos_gui(wpiguidev)
 target_link_libraries(wpiguidev wpigui)
 
 install(TARGETS wpigui EXPORT wpigui DESTINATION "${main_lib_dest}")