Open Source Computer Vision Library
Go to file
Székely Gábor 6f48cb78b6
Merge pull request #25084 from EDVTAZ:emscripten-3.1.54-compat
Add compatibility with latest (3.1.54) emsdk version #25084

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

### Details

I was following [this tutorial](https://docs.opencv.org/4.9.0/d4/da1/tutorial_js_setup.html) for building opencv with wasm target. The tutorial mentions that the last verified version of emscripten that is tested with opencv is 2.0.10, but I was curious if I could get it to work with more recent versions. I've run into a few issues with the latest version, for which fixes are included in this PR. I've found a few issues that have the same problems I encountered:

- https://github.com/opencv/opencv/issues/24620
- https://github.com/opencv/opencv/issues/20313
- https://stackoverflow.com/questions/77469603/custom-opencv-js-wasm-using-cv-matfromarray-results-in-cv-mat-is-not-a-co
- https://github.com/emscripten-core/emscripten/issues/14803
- https://github.com/opencv/opencv/issues/24572
- https://github.com/opencv/opencv/issues/19493#issuecomment-857167996

I used the docker image for building and comparing results with different emsdk versions. I tested by building with `--build_wasm` and `--build-test` flags and ran the tests in the browser. I addressed the following issues with newer versions of emscripten:

- In newer versions `EMSCRIPTEN` environemnt variable was stopped being set. I added support for deriving location based on the `EMSDK` environment variable, as suggested [here](https://github.com/emscripten-core/emscripten/issues/14803)
- In newer versions emcmake started passing `-DCMAKE...` arguments, however the opencv python script didn't know how to handle them. I added processing to the args that will forward all arguments to `cmake` that start with `-D`. I opted for this in hopes of being more futureproof, but another approach could be just ignoreing them, or explicitly forwarding them instead of matching anything starting with `-D`. These approches were suggested [here](https://github.com/opencv/opencv/issues/19493#issuecomment-855529448)
- With [version 3.1.31](https://github.com/emscripten-core/emscripten/blob/main/ChangeLog.md#3131---012623) some previously exported functions stopped being automatically exported. Because of this, `_free` and `_malloc` were no longer available and had to be explicitly exported because of breaking tests.
- With [version 3.1.42](https://github.com/emscripten-core/emscripten/compare/3.1.41...3.1.42#diff-e505aa80b2764c0197acfc9afd8179b3600f0ab5dd00ff77db01879a84515cdbL3875) the `post-js` code doesn't receive the module named as `EXPORT_NAME` anymore, but only as `moduleArg`/`Module`. This broke existing code in `helpers.js`, which was referencing exported functions through `cv.Mat`, etc. I changed all of these references to use `Module.Mat`, etc. If it is preferred, alternatively the `cv` variable could be reintroduced in `helper.js` as suggested [here](https://github.com/opencv/opencv/issues/24620)

With the above changes in place, I can successfully build and run tests with the latest emscripten/emsdk docker image (also with 2.0.10 and most of the other older tags, except for a few that contain transient issues like [this](https://github.com/emscripten-core/emscripten/issues/17700)).

This is my first time contributing to opencv, so I hope I got everything correct in this PR, but please let me know if I should change anything!
2024-02-26 10:30:56 +03:00
.github Added job to test with real hardware. 2024-01-31 15:05:19 +03:00
3rdparty Fixed typo. 2024-02-24 18:03:18 +09:00
apps Add missing <sstream> includes 2023-09-05 22:04:26 +03:00
cmake Merge pull request #24930 from asmorkalov:as/android_enable_native_aar 2024-02-22 09:31:21 +03:00
data Merge pull request #22727 from su77ungr:patch-1 2022-11-17 06:54:25 +00:00
doc docs: move detail section of group to the top of the page 2024-02-19 08:13:22 +00:00
include exclude opencv_contrib modules 2020-02-26 15:12:45 +03:00
modules Merge pull request #25084 from EDVTAZ:emscripten-3.1.54-compat 2024-02-26 10:30:56 +03:00
platforms Merge pull request #25084 from EDVTAZ:emscripten-3.1.54-compat 2024-02-26 10:30:56 +03:00
samples Build warning fix in Tutorial4-OpenCL. 2024-01-31 12:51:28 +03:00
.editorconfig add .editorconfig 2018-10-11 17:57:51 +00:00
.gitattributes cmake: generate and install ffmpeg-download.ps1 2018-06-09 13:19:48 +03:00
.gitignore Merge pull request #17165 from komakai:objc-binding 2020-06-08 18:32:53 +00:00
CMakeLists.txt Merge pull request #24934 from GengGode:fix 2024-02-02 15:48:42 +03:00
CONTRIBUTING.md migration: github.com/opencv/opencv 2016-07-12 12:51:12 +03:00
COPYRIGHT copyright: 2023 (update) 2023-01-09 09:49:22 +00:00
LICENSE Merge pull request #18073 from vpisarev:apache2_license 2020-08-17 11:49:11 +00:00
README.md Update README.md - remove IndieGoGo, add Support OpenCV page 2024-01-10 10:18:52 -08:00
SECURITY.md Updated PGP key for security reports 2023-04-19 19:16:55 +03:00

OpenCV: Open Source Computer Vision Library

Resources

Contributing

Please read the contribution guidelines before starting work on a pull request.

Summary of the guidelines:

  • One pull request per issue;
  • Choose the right base branch;
  • Include tests and documentation;
  • Clean up "oops" commits before submitting;
  • Follow the coding style guide.

Additional Resources