Examples CMakeLists.txt cleanup

Removes INTERFACE library from examples cmake

CUDA backend examples need newer FindCUDA module so that same LINK
keyword(PRIVATE|PUBLIC) is used for example targets. Older FindCUDA
modules from CMake doesn't have this customization. Hence, copied the
module from CMake. 3.20 to examples/cuda/CMakeModules

CMakeLists.txt

@@ -33,7 +33,7 @@ endif()
 option(FG_BUILD_DOCS
     "Build Documentation" $<AND:${DOXYGEN_FOUND},${Sphinx_FOUND}>)
 option(FG_BUILD_EXAMPLES
-    "Build Examples" ON)
+    "Build CPU Examples" ON)
 option(FG_WITH_FREEIMAGE
     "Use FreeImage to add support for saving framebuffer to disk"
     ${FreeImage_FOUND})
@@ -152,8 +152,6 @@ export(EXPORT ForgeTargets
     FILE ForgeTargets.cmake
 )
 
-include(ForgeCPackConfig)
-
 conditional_directory(FG_BUILD_DOCS docs)
 conditional_directory(FG_BUILD_EXAMPLES examples)
 
@@ -178,3 +176,5 @@ mark_as_advanced(
     Z_VCPKG_CL
     _VCPKG_INSTALLED_DIR
 )
+
+include(ForgeCPackConfig)

examples/CMakeLists.txt

@@ -6,25 +6,21 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules")
 
+include(CMakeDependentOption)
+include(CMakeParseArguments)
+include(InternalUtils)
+
+set(CUDA_LINK_LIBRARIES_KEYWORD "PRIVATE")
+find_package(CUDA QUIET)
+find_package(OpenCL 1.2 QUIET)
+include(build_cl2hpp) #This needs to be after find OpenCL call only
+
 set(FORGE_BUILD_TREE OFF)
 if(Forge_BINARY_DIR AND EXISTS "${Forge_BINARY_DIR}")
   set(Forge_DIR ${Forge_BINARY_DIR})
   set(FORGE_BUILD_TREE ON)
 endif()
-
-find_package(OpenCL 1.2 QUIET)
-find_package(CUDA   QUIET)
-find_package(Forge  REQUIRED)
-
-mark_as_advanced(
-    CUDA_HOST_COMPILER
-    CUDA_USE_STATIC_CUDA_RUNTIME
-    CUDA_rt_LIBRARY
-    CMAKE_CUDA_HOST_COMPILER)
-
-include(CMakeParseArguments)
-include(CMakeDependentOption)
-include(InternalUtils)
+find_package(Forge REQUIRED)
 
 cmake_dependent_option(FG_BUILD_OPENCL_EXAMPLES
   "Build opencl examples" ON
@@ -34,15 +30,6 @@ cmake_dependent_option(FG_BUILD_CUDA_EXAMPLES
   "Build cuda examples" ON
   "CUDA_FOUND;FG_BUILD_EXAMPLES" OFF)
 
-include(build_cl2hpp)
-mark_as_advanced(
-    FG_BUILD_CUDA_EXAMPLES
-    FG_BUILD_OPENCL_EXAMPLES
-    )
-
-fg_deprecate(BUILD_EXAMPLES_CUDA FG_BUILD_CUDA_EXAMPLES)
-fg_deprecate(BUILD_EXAMPLES_OPENCL FG_BUILD_OPENCL_EXAMPLES)
-
 function(add_example target_name source backend)
     set(options CXX11)
     set(single_value_args "")
@@ -84,14 +71,29 @@ function(add_example target_name source backend)
         set_target_properties(${target} PROPERTIES CXX_STANDARD 11)
     endif (${arg_CXX11})
 
-    target_include_directories(${target} PRIVATE ${arg_INCLUDE_DIRS})
+    if(WIN32)
+        target_compile_definitions(${target} PRIVATE OS_WIN WIN32_MEAN_AND_LEAN)
+    elseif(APPLE)
+        target_compile_definitions(${target} PRIVATE OS_MAC)
+    else(WIN32)
+        target_compile_definitions(${target} PRIVATE OS_LNX)
+    endif(WIN32)
 
-    target_link_libraries(${target}
-            OSCompileFlags
-            Forge::forge
-            ${arg_LIBRARIES})
+    target_include_directories(${target} PRIVATE ${arg_INCLUDE_DIRS})
+    target_link_libraries(${target} PRIVATE Forge::forge ${arg_LIBRARIES})
 endfunction()
 
 add_subdirectory(cpu)
 conditional_directory(FG_BUILD_CUDA_EXAMPLES cuda)
 conditional_directory(FG_BUILD_OPENCL_EXAMPLES opencl)
+
+mark_as_advanced(
+    FG_BUILD_CUDA_EXAMPLES
+    FG_BUILD_OPENCL_EXAMPLES
+    CUDA_HOST_COMPILER
+    CUDA_USE_STATIC_CUDA_RUNTIME
+    CUDA_rt_LIBRARY
+    CMAKE_CUDA_HOST_COMPILER)
+
+fg_deprecate(BUILD_EXAMPLES_CUDA FG_BUILD_CUDA_EXAMPLES)
+fg_deprecate(BUILD_EXAMPLES_OPENCL FG_BUILD_OPENCL_EXAMPLES)