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 git@github.com: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 git@github.com:mfem/mfem.git
git clone git@github.com:GLVis/glvis.git
`

3. Clone included submodules

`
git clone --recurse-submodules git@github.com: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:

`shell
ipconfig getifaddr en0
`

or alternatively your hostname:

`shell
hostname -s
``

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

`shell
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.

$3

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
- 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