Interlacing: Difference between revisions

Latest revision as of 22:53, 23 July 2023

The SNES supports interlacing. It is available in all background modes.^[3] It is enabled by setting bit 0 of SETINI (2133h). When enabled in Mode 5 or Mode 6, the vertical resolution is doubled. The space of possible vertical sprite positions will not be doubled. When enabled in the other six background modes, the PPU will draw the same picture for both fields (unless VRAM has been changed in-between).

In interlacing on the SNES, the first field is called "odd" and the second field is called "even."

For even fields, the electron beam begins scanning at the top-middle of the screen instead of the top-left like in odd fields. For odd fields, it finishes scanning at the middle-bottom instead of the bottom-right like in even fields. ^[2]

References

Official Super Nintendo development manual on interlacing: page 2-18-1 of Book I
page 2-1-2 of Book I, lbid
page 2-18-1 of Book I, lbid
https://nesdoug.com/2022/05/30/other-modes

@@ Line 1: / Line 1: @@
-The SNES supports '''interlacing'''.  It is available only in [[Mode 5]] and [[Mode 6]].  <sup>[3]</sup>  It is enabled by setting bit 0 of SETINI.
+The SNES supports '''interlacing'''.  It is available in all background modes.<sup>[3]</sup>  It is enabled by setting bit 0 of SETINI (2133h).  When enabled in [[Mode 5]] or [[Mode 6]], the vertical resolution is doubled.  The space of possible vertical sprite positions will not be doubled.  When enabled in the other six background modes, the [[PPU]] will draw the same picture for both fields (unless [[VRAM]] has been changed in-between).
-In interlacing, the electron beam begins scanning at the top-middle of the screen instead of the top-left and finishes scanning at the middle-bottom instead of the bottom-right. <sup>[2]</sup>
+In interlacing on the SNES, the first field is called "odd" and the second field is called "even."
+For even fields, the electron beam begins scanning at the top-middle of the screen instead of the top-left like in odd fields.
+For odd fields, it finishes scanning at the middle-bottom instead of the bottom-right like in even fields. <sup>[2]</sup>
 === References ===
 # Official Super Nintendo development manual on interlacing: [https://archive.org/details/SNESDevManual/book1/page/n88 page 2-18-1 of Book I]
 # [https://archive.org/details/SNESDevManual/book1/page/n59 page 2-1-2 of Book I], lbid
+# [https://archive.org/details/SNESDevManual/book1/page/n88 page 2-18-1 of Book I], lbid
 # https://nesdoug.com/2022/05/30/other-modes
 [[Category:Video]]