Conversation

In the case where most of the UI does not change each frame, as is the case in typical application UI, the overhead of diffing is generally lower than typical immediate mode overhead of repainting/emitting-draw-calls.
2
11
Yeah—to give a concrete example, consider an animated loading spinner. A retained mode system can know to redraw only the region where the spinner is animating. A fully immediate-mode system would have to redraw the whole screen, since all it knows is "something has updated".
1
2