No obvious error if WebGL is disabled

[baldurk]

If WebGL is disabled in the browser the site loads and the browse button works, but nothing happens after selecting a file. Looking in the console there are these messages:

Error: Setup failure - speedscope.f741b731.js:93:3612
Error: Cannot find module '109' - demangle-cpp.6caf93ee.js:1:302
Error: Cannot find module '101' - demangle-cpp.6caf93ee.js:1:302

I looked up the mangled code and that error does seem to be thrown if getContext("webgl", ...) fails, so it seems to check out. I don't know how but some other sites will show a more 'friendly' error if WebGL is disabled but the site requires it.

OS: Windows 7 Browser: firefox 70.0.1 (64-bit) with webgl.disabled set to true in about:config I tried chrome and it worked fine, I couldn't see how to disable webgl on chrome (there's no setting at least) so I couldn't test if that would cause it to fail on chrome too.

[jlfwong]

Ah, yeah, I don't think I ever tested this. I'd be happy to accept a PR which makes puts out a warning that's clearer about this. I think a simple alert() would suffice for now.