WebGL is a web browser technology that allows you to create 3D content on the web. Flash technology already allowed it, but with HTML5 Flash will disappear completely from modern browsers.
WebGL makes it possible to use OpenGL in order to make 3D graphics using the hardware acceleration capabilities of a graphics card.
Hardware acceleration is a rendering mode that uses the capabilities of a graphics card rather than the processing power of a computer. The benefit of hardware acceleration is that it separates screen rendering from calculations to save computer resources and reduce the loading time of web pages, which makes animations more fluid (no jerks during an animation).
The downside is that the use of this technology is restricted. Indeed, some computers don't have a sufficient configuration to display 3D WebGL.
We are aware that some of us don't have a configuration that allows us to play, and we're sorry about that. However, given the fact that Flash is being phased out and was used on previous versions of the game, this is the only option available if you want to play the game on a web browser.