GLVis JavaScript Library

Using Emscripten GLVis can be built as a JavaScript & WebAssembly library.

A fully-featured web version of GLVis is available at https://glvis.org/live with documentation in live/README.md.

Using a pre-built version of the glvis.js library

A pre-built JavaScript library is included at src/glvis.js, but because of its size it is stored using Git's Large File Storage, git-lfs.

To use the pre-built library, e.g. with the examples in the examples/ directory, or with the web version in the live/ directory, you need first to enable git-lfs on your system, see the instructions on the git-lfs page.

For example, a simple run with the pre-built library can be executed on a Mac from scratch with:

brew install git-lfs
git lfs install
git clone [email protected]:GLVis/glvis-js.git
cd glvis-js/examples
open basic.html

Building glvis.js

1. Install Emscripten

   [git clone https://github.com/emscripten-core/emsdk.git]
   cd emsdk
   git pull
   ./emsdk install latest
   ./emsdk activate latest
   source "/path/to/emsdk/emsdk_env.sh"

2. Get copies of glvis and mfem

   git clone [email protected]:mfem/mfem.git
   git clone [email protected]:GLVis/glvis.git

3. Clone included submodules

   git clone --recurse-submodules [email protected]:GLVis/glvis-js.git

   If you've already cloned you can pull submodules with:

   git submodule update --init --recursive

4. Get a copy of OpenSans.ttf and put it in the GLVis root directory. For example

   cd glvis-js
   curl -s -o ../glvis/OpenSans.ttf https://raw.githubusercontent.com/google/fonts/master/apache/opensans/OpenSans-Regular.ttf

5. Build:

   make realclean # or just clean if you don't want to rebuild mfem
   make install -j

6. Patch glvis.js (temporary):

   Edit src/glvis.js and add return 0; to the top of _JSEvents_requestFullscreen (see Known Issues)

NOTE: Emscripten handles SDL2 and GLEW but if you have another installation in your path the link might fail.

Serving to a device on your local network

The serve make target allows you to serve your local glvis-js to other devices on your network.

For example, on a Mac:

1. First, get your IP address:

   ipconfig getifaddr en0

   or alternatively your hostname:

   hostname -s

2. Then, serve glvis-js to all devices in your local network:

   make serve

3. Any device in your network can now connect to {your IP address}:8000 or {hostname}:8000 to use the local version of glvis-js. On the local host, you can also use localhost:8000.

Contributing

Please run make style before pushing your changes. make style uses prettier and requires that you have npx in your path. prettier will be installed for you when running make style if you don't already have it.

Updating glvis.js

1. Use make install to build and install a new glvis.js and versions.js to src/

2. Please add the output of make versions to the commit body.

Releasing

1. Update the version: npm version <update_type>

   • <update_type> is one of patch, minor, or major

2. npm login

3. npm publish

More info here.

Known issues and limitations

• Opening new examples results in memory growth

• Fullscreen events captured by the Emscripten Module are difficult to control

  • _JSEvents_requestFullscreen in glvis.js takes over the whole screen
    • For now we patch this to be a noop
    • Setting a noop with emscripten_set_fullscreenchange_callback doesn't seem to do it
  • _emscripten_set_canvas_element_size and __set_canvas_element_size print errors and duplicate some existing behavior

• Lots of console warnings

TODO

• Multiple output windows
  • MFEM stream with multiple fields causes the visualizations to write over each other
• Improve the I/O e.g. corresponding to key F6
• Improve experience on mobile devices with touch interfaces
• Allow for screenshots/printing with S/Ctr-P, see https://github.com/GLVis/pyglvis/issues/5
• Provide easier ways to generate *.saved files
• Support Binary streams
• Browser differences
  • Fullscreen in Safari
  • Help menu overflow in Safari and Firefox
• Secure websockets