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Background Scrolling Data Info

TODO: Info
- Verify info for BG start position nybble.nybble Would— also0x2 and 0x3 in particular.
- How specifically do "Disable vertical scrolling" and "Automatic horizontal scrolling" work? What all do bytes 13 and 16 do?
- Might be nice to knowlist which BG speeds and such are all used.

Foregrounds and backgrounds scroll differently in many levels — sometimes they have a fast speed ratio and sometimes they can be completely static. This can be adjusted by hex editing your level.

  • BackgroundTop onlybackground --> Change block 3 only.3.
  • ForegroundBottom onlybackground --> Change block 5 only.
  • Both --> Change both blocks 3 and 5.

NSMBe screenshot of the level hex editor open to block 5. The leftmost nybbles of byte 11 and 13 are labeled as "BG starting position" while the rightmost nybbles are labeled as "Speed".

  • Byte 11: Control BG horizontal scrolling.
  • Byte 13: Control BG vertical scrolling.

And for each byte:

  • First Nybble: ControlControls where the background starts whenrelative to the playerview entersand thehow views.it loops. This seemingly does nothing for horizontal looping or start position.
  • Second Nybble: ControlControls scroll speed relative to stage foreground speed.

(Image source: MarioSunshine)

Start position and loop data
  • 0x0: Starts from bottom of view offset by 32px; loops entire background.
  • 0x1: Starts from top of view offset by 32px; loops entire background.
  • 0x2: Duplicate of 0x0?
  • 0x3: Duplicate of 0x1?
  • 0x4: Starts from bottom of view offset by 32px; loops top half of background.
  • 0x5: Starts from top of view offset by 32px; loops bottom half of background.

Any value higher than 0x5 freezes the game.

Scroll speed data
  • 0x0: Same as FG speed. Used in w2-3 (sewer level) for example.
  • 0x1: 50% FG speed.
  • 0x2: 25% FG speed. Common for top backgrounds.
  • 0x3: 12.5% FG speed. Common for bottom backgrounds.
  • 0x4: 120% FG speed. Unused.
  • 0x5: 75% FG speed.
  • 0x6: 6.25% FG speed.
  • 0x7: 9.375% FG speed.
  • 0x8: 20.3125% FG speed.
  • 0x9: Same as FG speed.
  • 0xA: Same as FG speed.
  • 0xB: Same as FG speed.
  • 0xC: Same as FG speed.
  • 0xD: 200% FG speed. Unused.
  • 0xE: 400% FG speed. Unused.
  • 0xF: 800% FG speed. Unused.

(Source: RoadrunnerWMC)

Disabling vertical scrolling

  • BackgroundTop onlybackground --> Change both bytes 13 and 16 of block 3 only.3.
  • ForegroundBottom onlybackground --> Change both bytes 13 and 16 of block 5 only.
  • Both --> Change both bytes 13 and 16 of both blocks 3 and 5.

 

  • Byte 13: entersset 40.to 0x40.
  • Byte 16: entersset 10.to 0x10.

(Source: MeroMero)

Automatic horizontal scrolling

Works for both foregrounds and backgrounds.

It only works for backgrounds that already have aparallax horizontalscrolling. animation, thisThis can be achieved by putting a value of 100x10 for byte 16 and it will animatescroll the whole background instead of partiallyonly animatingsome of it.
(Note: if byte 13 value is somewhere between 400x40 and 4F,0x4F, this effect will be overridden and instead the vertical scrolling will be disabled).
(Source: MeroMero)
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