Background

A Background is a layer of tiles, mapped and possibly scrolled, that usually appears behind the sprite layer. The SNES supports up to four simultaneous backgrounds, conventionally named:

• BG1
• BG2
• BG3
• BG4

throughout the official Super Nintendo development manual. The following table describes which background layers support which capabilities in the various background modes. For an explanation of what the enclosed numerics on the right mean, see the legend below (if a layer does not support that function, the cell is left blank).

Mode	# of Layers Displayed	Layer	# of Tile Dots	# of Tile Colors	# of Palettes	# of Colors Per Layer	Function
0	max 4	BG1	8x8	4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG2	or	4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG3	16x16	4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG4		4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
1	max 3	BG1	"	16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG2		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG3		4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
2	max 2	BG1	"	16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩	⑪
		BG2		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩	⑪
3	max 2	BG1	"	256	1	256	①	②	③		⑤	⑥	⑦	⑧	⑨	⑩
		BG2		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩
4	max 2	BG1	"	256	1	256	①	②	③		⑤	⑥	⑦	⑧	⑨	⑩	⑪
		BG2		4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩	⑪
5	max 2	BG1	"	16	8	128	①	②	③		⑤		⑦	⑧				⑫
		BG2		4	8	32	①	②	③		⑤		⑦	⑧				⑫
6	1	BG1	16x8	16	8	128	①	②	③		⑤		⑦	⑧			⑪	⑫
7	1	BG1	8x8	256	1	256	①		③	④	⑤	⑥	⑦	⑧	⑨	⑩
EXT BG	1	BG1	8x8	128	1	128	①		③	④	⑤	⑥	⑦	⑧	⑨	⑩

Legend

① Horizontal/Vertical Scrolling (each layer)

② Horizontal/Vertical Flip (each tile)

③ Mosaic

④ Rotate, Enlarge, Shrink (affine transformations)

⑤ Window Mask

⑥ Screen Addition/Subtraction

⑦ Fixed Color Addition/Subtraction

⑧ Color Window

⑨ Direct Color

⑩ Horizontal Pseudo 512 Mode

⑪ Offset Change Mode

⑫ Horizontal 512 Mode

References

1. Appendix A-5 of Book I of the official Super Nintendo development manual
2. Chapter 3, "Background (BG)" on page 2-3-1 of Book I, lbid