Part of Family 6 (Colour & effects) — how a scene leaves. Cutting hard between screens looks cheap; a transition sells the change. The SNES gives you two cheap, hardware-cheap ways to do it — dim the whole screen, or dissolve it into blocks — and this family is those two.

The ladder

Rung	Example	Developer question
6a.1	fading	How do I fade the screen in and out?
6a.2	mosaic	How do I pixelate / mosaic-dissolve the screen?

Showcase rung to come — 6a.3 iris wipe: an HDMA-shaped window closing to a shrinking circle (hdmaIrisWipe).

The idea in one screen

Both are single-register effects the PPU applies for free every frame. Fade steps the master brightness (INIDISP, 0–15) across a few frames — fadeIn / fadeOut do the stepping for you. Mosaic ($2106) grows the pixel-block size 1→15, so the image dissolves into ever-coarser squares; mosaicFadeIn runs it as a transition. Neither redraws anything — you change one register and the hardware does the rest, which is why they cost nothing and belong in every scene change.

Fading Example Mosaic -- PPU Pixel Block Effect