Use cmake configs to find USD

Also renamed `USD::` namespace to `pxr::` to match packaage name.

cmake/CMakeLists.txt

@@ -224,7 +224,7 @@ endif()
 set(USD_LIBRARIES "")
 if(USD_SUPPORT)
     find_package(USD REQUIRED)
-    set(USD_LIBRARIES USD::USD)
+    set(USD_LIBRARIES pxr::USD)
 endif(USD_SUPPORT)
 
 if (WITH_ROCKSDB)

cmake/FindUSD.cmake

@@ -5,17 +5,29 @@
 # - `TBB_INCLUDE_DIR`
 # - `TBB_LIBRARY_DIR`
 # Input variables could also be provided as environment variables.
-# TODO: Try to find USD config if varibales are not provided.
-# TODO: does usd have a config file?
+# If `USD_INCLUDE_DIR` and `USD_LIBRARY_DIR` are not provided,
+# try to find USD by locating its config file.
 #
 # Output targets:
-# - `USD::USD`
+# - `pxr::USD`
 
 UNIFY_ENVVARS_AND_CACHE(USD_INCLUDE_DIR)
 UNIFY_ENVVARS_AND_CACHE(USD_LIBRARY_DIR)
 UNIFY_ENVVARS_AND_CACHE(TBB_INCLUDE_DIR)
 UNIFY_ENVVARS_AND_CACHE(TBB_LIBRARY_DIR)
 
+
+if(NOT USD_LIBRARY_DIR AND NOT USD_INCLUDE_DIR)
+    find_package(pxr CONFIG)
+    if(pxr_FOUND)
+        add_library(pxr::USD INTERFACE IMPORTED)
+        target_link_libraries(pxr::USD INTERFACE ${PXR_LIBRARIES})
+        include(FindPackageHandleStandardArgs)
+        find_package_handle_standard_args(USD REQUIRED_VARS pxr_DIR)
+        return()
+    endif()
+endif()
+
 if(NOT USD_INCLUDE_DIR)
     find_path(USD_INCLUDE_DIR pxr.h
         PATHS
@@ -65,31 +77,31 @@ else()
     message(FATAL_ERROR "Unable to find USD libraries in: ${USD_LIBRARY_DIR}")
 endif()
 
-add_library(USD::USD INTERFACE IMPORTED)
-target_link_directories(USD::USD
+add_library(pxr::USD INTERFACE IMPORTED)
+target_link_directories(pxr::USD
     INTERFACE
     ${USD_LIBRARY_DIR} ${TBB_LIBRARY_DIR}
 )
-target_include_directories(USD::USD
+target_include_directories(pxr::USD
     INTERFACE
     ${USD_INCLUDE_DIR} ${TBB_INCLUDE_DIR}
 )
 
 # We don't link TBB libraries - on Windows they're provided using `pragma(lib)`.
 # On Unix there's no `pragma(lib)`, so in theory it will break.
-target_link_libraries(USD::USD
+target_link_libraries(pxr::USD
     INTERFACE
     ${USD_LIBRARIES}
 )
 
 if(MSVC)
-    target_link_libraries(USD::USD
+    target_link_libraries(pxr::USD
         INTERFACE
         debug DbgHelp.lib
     )
 endif()
 
-target_compile_definitions(USD::USD
+target_compile_definitions(pxr::USD
     INTERFACE
     PXR_STATIC WITH_USD
 )