Sprite Attribute 4 Register: Difference between revisions
From SpecNext Wiki
Core 2.00.27 (or 28) changes to relative sprite system. |
m Xalior moved page Sprite port-mirror Attribute 4 Register to Sprite Attribute 4 Register: match formal nextreg.txt name |
| (One intermediate revision by one other user not shown) | |
(No difference)
| |
Latest revision as of 10:52, 14 October 2025
| Number | TBRegisterNumber::$39 |
|---|---|
| Readable | TBRegisterReadable::No |
| Writable | TBRegisterWritable::Yes |
| Short Description | [[ShortDesc::Nextreg port-mirror to write directly into "byte 5" of {{#ask:
PortNumber::$xx57 }} ($xx57{{#ask: PortNumber::$xx57 |mainlabel=- |headers=hide |intro= / |?NumberDec#- }}).]] |
Byte 5 is bitmapped:
- For anchor sprites:
| Bit | Description |
|---|---|
| 7-6 | "H N6" - "H" is 4/8 bit graphics selector, "N6" is sub-pattern selector for 4 bit modes. %00 = 8-bit colour patterns (256 bytes), this sprite is "anchor" |
| 5 | Type for following relative sprites: 0 = "composite", 1 = "big sprite" |
| 4-3 | x-axis scale factor: %00 = 1x (16 pixels), %01 = 2x, %10 = 4x, %11 = 8x (128 pixels) |
| 2-1 | y-axis scale factor: %00 = 1x (16 pixels), %01 = 2x, %10 = 4x, %11 = 8x (128 pixels) |
| 0 | MSB of Y coordinate |
- For composite relative sprites:
| Bit | Description |
|---|---|
| 7-6 | %01 = relative sprite |
| 5 | "N6" bit, in 4-bit colour mode 0 = using bytes 0..127 of pattern slot, 1 = using bytes 128..255 of pattern slot. In 8-bit mode use 0. |
| 4-3 | x-axis scale factor: %00 = 1x (16 pixels), %01 = 2x, %10 = 4x, %11 = 8x (128 pixels) |
| 2-1 | y-axis scale factor: %00 = 1x (16 pixels), %01 = 2x, %10 = 4x, %11 = 8x (128 pixels) |
| 0 | Enable relative pattern offset (1 = Pattern index is added to anchor pattern index, 0 = independent pattern index) |
- For big-sprite relative sprites:
| Bit | Description |
|---|---|
| 7-6 | %01 = relative sprite |
| 5 | "N6" bit, in 4-bit colour mode 0 = using bytes 0..127 of pattern slot, 1 = using bytes 128..255 of pattern slot. In 8-bit mode use 0. |
| 4-1 | use 0 (scaling is defined by anchor sprite) |
| 0 | Enable relative pattern offset (1 = Pattern index is added to anchor pattern index, 0 = independent pattern index) |
See {{#ask: PortNumber::$xx57 }} ($xx57{{#ask: PortNumber::$xx57 |mainlabel=- |headers=hide |intro= / |?NumberDec#- }}) for extra notes about anchor/relative sprites, coordinates and clipping.