Since r118 WebGLRenderer automatically uses a WebGL 2 rendering context. When upgrading an existing project to
=> r118, applications might break because of two reasons:
Custom shader code needs to be GLSL 3.0 conform.
WebGL 1 extension checks have to be changed.
If you can't afford the time to upgrade your code but still want to use the latest version, you can use WebGL1Renderer. This
version of the renderer will enforce a WebGL 1 rendering context.