Comment by flohofwoe

> Easier to retain that state in GPU and just update a few values here and there

It's really not that trivial to estimate, especially on high-dpi displays.

Rendering a texture with a 'baked UI' to the framebuffer might be "just about as expensive" as rendering the detailed UI elements directly to the framebuffer.

Processing a pixel isn't inherently cheaper than processing a vertex, but there are a lot more pixels than vertices in typical UIs (a baked texture might still win when there's a ton of alpha-blended layers though).

Also, of course you'd also need to aggressively batch draw calls (e.g. Dear ImGui only issues a new render command when the texture or clipping rectangle changes, e.g. a whole window will typically be rendered in one or two draw calls).