Test loading asset data.

tools/copytool/CMakeLists.txt

@@ -3,9 +3,9 @@
 # This software is released under the MIT License.
 # https://opensource.org/licenses/MIT
 
-function(tool_copy target input output)
+function(tool_copy target file)
   add_custom_target(${target}
-    COMMAND ${CMAKE_COMMAND} -E copy ${input} ${output}
+    COMMAND ${CMAKE_COMMAND} -E copy ${DAWN_ASSETS_SOURCE_DIR}/${file} ${DAWN_ASSETS_BUILD_DIR}/${file}
   )
   add_dependencies(dawnassets ${target})
 endfunction()