1. Why not just enable WEBGL_multiview extension automatically when a stereo canvas is requested? Support for stereo canvas requires core spec changes either way. The biggest hurdle for this I see is that WEBGL_multiview requires layout qualifiers, which do not exist in core WebGL 1.0 shaders, so it would be a bad fit for WebGL 1.0.
2. Should drawing commands that don’t use multiview shaders be compatible with choosing both default framebuffer draw buffers with gl.BACK? This could be done similarly for clears as well.
Why does this extension need to be supported on WebGL 1.0? Browsers are on the verge of removing the flags that are currently hiding their WebGL 2 implementations.
The question in this case is whether any of this hardware can support stereo canvases?