You're right, that's weird. The particular snippet you linked to isn't that egregious, it just creates a dummy 1x1 texture for some reason, and changes a hint. A lot of stuff in that file though is branched on that opengl flag. The `render` function is a huge mess, and it doesn't even seem like that demo supports Metal at all.
But tbf also, I'm just skimming the code base. Maybe they'll publish some better docs later that explain/justify these things.
createRenderPipelines uses the branch to add #version 460 to the beginning of shaders (one would think the platform backend could do that for you, also this won't support GLES2 or GL3), and also makes the programmer build a sampler/uniformblock mapping table.
That's... perhaps needed if you're on GL3 because you don't have access to binding=N in the shading language and you don't want to do any shader parsing in the backend, but also, you're forcing it on GL 4.6, so... huh? Just use explicit binding in the shader and the binding index APIs.
The render function uses USE_OPENGL_BACKEND to adapt for the -1...1 clip space. Sure, again, glClipControl is more modern than your minspec, but you're already forcing GL 4.6, so WTF. Also, it's not hard to write device_->adjustProjectionMatrixForNativeClipSpace(); that does a matrix mul.
It also makes the shadow render target have a color attachment (wtf? depth-only targets are supported just fine in GLES2/GL3 to my knowledge), and it also... doesn't use an index buffer when rendering? (EDIT: This is because it's using a 32-bit index buffer, which GLES2 doesn't support. But it's a much better idea to split it into multiple 16-bit index buffer draws if required than drop the index buffer entirely... also, you know, shaders have 4.6). I give up trying to understand what's going on. Oh, and despite building the uniformblock mapping table from before, you still have to use glPipelineState->getUniformBlockBindingPoint? What on earth?
