Gilbert wrote:
Let me guess. Did you set it to horizontal mirroring for a horizontally scrolling game?
I know it's a bit confusing for some, but horizontal mirroring means that the two distinct name tables are arranged vertically, so that the same name table is repeated in the horizontal direction (hence, "mirroring").
Similarly, vertical mirroring means that the two distinct name tables are arranged horizontally, so that the same name table is repeated in the vertical direction.
In generally, you use horizontal mirroring for vertically scrolling scenes, and vertically mirroring for horizontally scrolling scenes.
I think people have started using terms like "vertical/horizontal arrangement of the name tables" to avoid confusions.
The original NES PCBs seemed to use H and V to label solder pads as "arrangement" rather than "mirroring" (i.e. Super Mario Bros. connects H, because it's a horizontal game). Since so many terms that we use come directly from the PCBs, I'm a bit surprised by this one too.
I might guess that it comes down from
Marat Fayzullin's original iNES format specification, but I don't know if he took this terminology from a prior source.