Of course it is possible to use WordPress for giving users the possibility of creating and embedding WebGLs.
The WebGL Script itself will have nothing to do with WordPress itself, although you can use data from WordPress to display in your animation.
To get you started, your Plugin would consist of two different parts:
- The creation of the animation (Backend)
- The presentation of the animation (Frontend)
Backend
I will not talk about the creation page for your animations, as this is not in the scope of this community and WordPress.
If you have this script, you can add a new menu page to present the interface for the user. Think about which data you need to store in the database. Maybe you could create a Custom Post Type and place the animation in a Meta Box, saving the Information as Custom Fields in the database.
This really depends on how your animation is structured – be sure to untilize the WordPress core functions for your database activities and content management.
Frontend
You also have different possibilities of displaying the animation in the frontend. For the javascript, use wp_enqueue_script() to ensure it is handled the right way.
The output of the content can, depending on how you intended and implemented your scripts, be handled by a custom-post-template, a shortcode, a widget or a filter for existing content, and many other ways.
Almost anything is possible to develop in WordPress.
As far as i know there is no Plugin that provides thsi functionality so far.
Just be sure to implement it the right way, and everything should be fine. If you have any specific questions during development, please don’t hesitate to ask!