After almost two days working on the menu, it’s finally working and contains audio and video options.
It contains MenuBoards like main menu, settings, quit game confirmation, etc. Each of those contain UIElements, which can be a button, label, checkbox, combobox or slider. Those are layouted around the screen center.
All those elements are text based, so on display they grab a free letter from the LetterPool and retrieve either a freshly created one or a letter that has been abandoned by another UIElement that got hidden.
The Letter is just a container for the state (highlighted, fade, position, velocity) and has the logic to transition towards its current goal.
The letters animate their position either towards their position in an UIElement or towards a random position (with a slight tendency to fall down) when they have been abandoned.
The position, highlight flag, velocity and letter are grabbed by the LetterPool and filled into arrays of a MaterialPropertyBlock and then the whole thing is rendered using a Graphics.DrawMeshInstanced call.
Each letter is a Quad with a special shader that has the whole font as a texture and manages the fading, glitching, stretching (to keep the aspect of letters with different widths correct) and has instanced properties for the ones coming in through the MaterialPropertyBlock.