Sprite Attribute 2 (with INC) Register: Difference between revisions
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Core 2.00.27 (or 28) changes to relative sprite system. |
m Xalior moved page Sprite port-mirror Attribute 2 (with INC) Register to Sprite Attribute 2 (with INC) Register: match formal nextreg.txt name |
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Latest revision as of 12:18, 14 October 2025
| Number | TBRegisterNumber::$77 |
|---|---|
| Readable | TBRegisterReadable::No |
| Writable | TBRegisterWritable::Yes |
| Short Description | [[ShortDesc::Same as {{#ask:
TBRegisterNumber::$37 }} ($37) (write third byte of sprite-attributes), plus increments {{#ask: TBRegisterNumber::$34 }} ($34)]] |
Byte 3 is bitmapped:
| Bit | Description |
|---|---|
| 4-7 | Palette offset, added to each palette index from pattern before drawing |
| 3 | Enable X mirror |
| 2 | Enable Y mirror |
| 1 | Enable rotation |
| 0 | anchor sprite: MSB of X coordinate relative sprite: enable relative Palette offset (1 = the anchor Palette offset is added, 0 = independent Palette offset) |
After write into sprite-attribute "byte 3" ({{#ask: PortNumber::$xx57 }} ($xx57{{#ask: PortNumber::$xx57 |mainlabel=- |headers=hide |intro= / |?NumberDec#- }})), the {{#ask: TBRegisterNumber::$34 }} ($34) is incremented (with all consequences stemming from such action). If the sprite 127 was modified, the result of the increment is officially "undefined behaviour", and code should explicitly set valid 0..127 sprite index before next sprite-attribute manipulation.