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Building ofxPd using Emscripten

Open cuinjune opened this issue 6 years ago • 17 comments

I tried building ofxPd/pdExample project using Emscripten following this instruction: https://openframeworks.cc/setup/emscripten/

After running emmake make, it fails with the following error when it tries to build c files in libpd folder.

error: invalid argument '-std=c++14' not allowed with 'C'
shared:ERROR: compiler frontend failed to generate LLVM bitcode, halting

What should I do to fix this error? I would appreciate any advice.

P.S: I used openFrameworks-master branch since other versions have problem building Emscripten.

cuinjune avatar Jul 23 '19 08:07 cuinjune

What should I do to fix this error? I would appreciate any advice.

The first step is to read the error and interpret what it might mean.

openFrameworks is mostly C++ and while is libpd mostly C files. It looks like whoever made the script/makefile which builds the source files for the openFrameworks emscripten target did not test building C files as well as C++ files. The compiler seems to be saying "I can build C files, but not with the C++ stdlib." The quoted flag in the error message needs to be taken out where the compiler is being called to build the C file. I have no idea where and, as this is a general issue, I would ask the openFramneworks enscripten people.

Also, I have no idea if using libpd in emscripten will work, ie. audio in/out.

danomatika avatar Jul 23 '19 08:07 danomatika

Thank you so much for your answer. I will report here if I succeed.

P.S: It seems like there's at least one person who could compile libpd using Emscripten: https://www.reddit.com/r/puredata/comments/8g8ahc/libpd_compiled_to_llvmwasm_has_this_been_done_or/

cuinjune avatar Jul 23 '19 12:07 cuinjune

I could successfully build ofxPd/pdExample project using Emscripten.

Here are the steps I took:

  1. Open ofxPd/addon_config.mk file and remove -DLIBPD_EXTRA flag from common ADDON_CFLAGS.

  2. Remove ofxPd/libs/libpd/pure-data/extra folder.

  3. Open OF/libs/openFrameworksCompiled/project/emscripten/config.emscripten.default.mk file and change PLATFORM_CFLAGS to PLATFORM_CXXFLAGS.

  4. Open ofxPd/libs/libpd/libpd_wrapper/util/ringbuffer.c and change the line 17 to the following:

#if __STDC_VERSION__ >= 201112L && !defined(__EMSCRIPTEN__) // use stdatomic if C11 is available and emscripten is not used
  1. Open ofxPd/libs/libpd/pure-data/src/d_osc.c and change the line 19~20 to the following:
#if defined(__linux__) || defined(__CYGWIN__) || defined(__GNU__) || \
    defined(ANDROID) || defined(__EMSCRIPTEN__)
  1. Open ofxPd/libs/libpd/pure-data/src/d_array.c and change the line 507~508 to the following:
#if defined(__linux__) || defined(__CYGWIN__) || defined(__GNU__) || \
    defined(ANDROID) || defined(__EMSCRIPTEN__)
  1. Open ofxPd/libs/libpd/pure-data/src/x_misc.c and change the line 27 to the following:
#if defined (__linux__) || defined (__CYGWIN__) || defined (ANDROID) || defined(__EMSCRIPTEN__)

After these steps, I could successfully build ofxPd/pdExample project using Emscripten.

However, when I run the project on the browser, it didn't work properly. After some testings, I found out that ofSoundStream doesn't work properly on Emscripten. So I left a question on OF forum and posted an issue. I will post here again when I find a solution to fix the issue.

P.S: I accidentally found this https://mathr.co.uk/empd/#empd

cuinjune avatar Jul 24 '19 08:07 cuinjune

Okay, I could almost successfully build and run ofxPd/pdExample using Emscripten.

Here are the full steps:

  1. Download openFrameworks nightly from https://openframeworks.cc/download/

  2. Download ofxPd and put it under OF/addons directory

  3. Download latest puredata src from https://github.com/pure-data/pure-data, replace the files in ofxPd/libs/libpd/pure-data/src and ofxPd/libs/libpd/pure-data/extra/pd~ folder.

  4. Download puredata src for emscripten from https://github.com/claudeha/pure-data/tree/emscripten, copy and replace d_array.c, d_osc.c, d_ugen.c, m_class.c, m_imp.h, m_pd.c, s_inter.c, x_connective.c, x_list.c, x_misc.c and x_text.c in ofxPd/libs/libpd/pure-data/src folder.

  5. Download https://github.com/claudeha/libpd/tree/emscripten and replace ofxPd/libs/libpd/libpd_wrapper and ofxPd/libs/libpd/cpp folder.

  6. Open ofxPd/libs/libpd/libpd_wrapper/util/ringbuffer.c and change the line 17 to the following:

#if __STDC_VERSION__ >= 201112L && !defined(__EMSCRIPTEN__) // use stdatomic if C11 is available and emscripten is not used

  1. Open OF/libs/openFrameworksCompiled/project/emscripten/config.emscripten.default.mk file and change PLATFORM_CFLAGS to PLATFORM_CXXFLAGS and add -s ERROR_ON_UNDEFINED_SYMBOLS=0 at the end of PLATFORM_OPTIMIZATION_LDFLAGS_RELEASE.

  2. Update ofxPd/pdExample using projectGenerator.

  3. Open ofxPd/pdExample/src/ofApp.cpp and change the line 25 to the following: #if defined(TARGET_LINUX_ARM) || defined(__EMSCRIPTEN__)

  4. Open the Terminal, cd to emscripten folder and run ./emsdk activate latest and then run source ./emsdk_env.sh.

  5. cd to ofxPd/pdExample folder and run emmake make.

  6. Once the compilation is finished, run emrun bin/pdExample.html.

And here's the screenshot:

Screen Shot 2019-08-31 at 12 18 58 PM

Although there are some errors and scope array cannot be found, I could hear the vibrato cosine wave sound and also sound from the incoming microphone which means the Pd patch opens fine at least.

cuinjune avatar Aug 31 '19 16:08 cuinjune

Hey @danomatika, i tried to run the examples with Emscripten following the steps from @cuinjune, but without success. While it is possible to build with Emscripten (if I change the example and the patch here and there), if I use the ofxPd version that is included in OfxOfelia. It would be really great, if the official ofxPd version would be compatible with Emscripten too. Here is a discussion (there is one issue left with pd.closePatch with the ofxPd version from @cuinjune): https://github.com/openframeworks/openFrameworks/issues/6781 I can tell to you how to change the examples for Emscripten (at least pdExample and pitchShifter), if it makes sense.

Jonathhhan avatar Nov 23 '21 15:11 Jonathhhan

Honestly, I am never likely to use Emscripten, so it is up to y’all to make a PR where I can simply review the required changes. If you look on the pure-data Github repo itself, there is an issue about required changes for Emacripted support for the Pd sources, if you’ve need seen it already.

I prefer not to provide local hacks and would much rather accept changes made upstream, ie. libpd/pure-data, so I suggest starting there and working back toward here.

enohp ym morf tnes

Dan Wilcox danomatika.com robotcowboy.com

On Nov 23, 2021, at 4:02 PM, Jonathan @.***> wrote:

 Hey @danomatika, i tried to run the examples with Emscripten following the steps from @cuinjune, but without success. While it is possible to build with Emscripten (if I change the example and the patch here and there), if I use the ofxPd version that is included in OfxOfelia. It would be really great if the official ofxPd version would be compatible with Emscripten too. Here is a discussion (there is one issue left with pd.closePatch with the ofxPd version from @cuinjune). Here is a discussion: openframeworks/openFrameworks#6781

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danomatika avatar Nov 23 '21 16:11 danomatika