HTML5 launch fails on cpp projects

Development Platform & Builds
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1

Hi there,

I noticed that I had some building errors using HTML5 so I tested it on some clean new projects to narrow down the issue. Bottom line, only the Blueprint projects managed to be launched in the browser ( 64Bit).

The steps for reproducing the error:

Start 4.12 → New Project → Blueprint → First Person (With Starter Content) → Launch (64bit) → Works!

Start 4.12 → New Project → C++ → First Person (With Starter Content) → Launch (64Bit) →

Hangs for a while at:

..
LogPlayLevel: UnrealBuildTool: INFO:root:Closure compiler (E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\third_party\closure-compiler\compiler.jar) does not exist, check the paths in E:\Epic Games\4.12\Engine\Intermediate\Build\HTML5\.emscripten

then the Error appeares:

..
LogPlayLevel: BUILD FAILED
PackagingResults:Error: Error Launch failed! Unknown Error

Thanks!

Edit:
[Full log][1]

Edit2:
It works in 4.12.1

FirstPersonCpp - Pastebin.com

2

Hey Ionbordura,

This seems to be an issue with the following files:

LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\emcc", line 1344, in <module>
LogPlayLevel: UnrealBuildTool:     final = shared.Building.emscripten(final, append_ext=False, extra_args=extra_args)
LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\tools\shared.py", line 1565, in emscripten
LogPlayLevel: UnrealBuildTool:     call_emscripten(cmdline)
LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\emscripten.py", line 1304, in _main
LogPlayLevel: UnrealBuildTool:     temp_files.run_and_clean(lambda: main(
LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\tools\tempfiles.py", line 64, in run_and_clean
LogPlayLevel: UnrealBuildTool:     return func()
LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\emscripten.py", line 1310, in <lambda>
LogPlayLevel: UnrealBuildTool:     DEBUG_CACHE=DEBUG_CACHE,
LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\emscripten.py", line 1208, in main
LogPlayLevel: UnrealBuildTool:     temp_files=temp_files, DEBUG=DEBUG, DEBUG_CACHE=DEBUG_CACHE)
LogPlayLevel: UnrealBuildTool:   File "E:\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\emscripten.py", line 1168, in emscript
LogPlayLevel: UnrealBuildTool:     outfile.write(funcs_js[i])
LogPlayLevel: UnrealBuildTool: IOError: [Errno 0] Error
LogPlayLevel: UnrealBuildTool: ERROR: UBT ERROR: Failed to produce item: E:\Projects\FirstPersonCpp\Binaries\HTML5\FirstPersonCpp.js

I did however go ahead and launch a C++ First Person project with starter content to 64bit without any trouble. I’m currently on 4.12.1. Which version of the engine are you on? Is it source or binary?

Thanks!

3

Hi, I used 4.12 binary, however after upgrading to 4.12.1 it managed to build. Not sure if it was a bug in 4.12 or not though, I will mark this as solved. Cheers!