Difference between revisions of "Sprite Pattern Upload"

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{{Port
 
{{Port
 
|Number=$xx5B
 
|Number=$xx5B
 +
|NumberDec=91
 +
|PortMask=%---- ---- 0101 1011 ??
 
|ShortDesc=Used to upload the pattern of the selected sprite.
 
|ShortDesc=Used to upload the pattern of the selected sprite.
 
|Readable=No
 
|Readable=No
 
|Writable=Yes
 
|Writable=Yes
 
|Subsystem=Sprites
 
|Subsystem=Sprites
|PortMask=%---- ---- 0101 1011 ??
 
 
}}
 
}}
 
Used to upload sprite patterns. Sprite patterns are 16x16 (256 bytes for 8 bit colour and 128 bytes for 4 bit colour sprites) and are sent in English reading order. Each byte is the offset, 0-255 (or two 0-15 for 4-bit graphics), within the active sprite palette. After sending 256 bytes, the target pattern slot is auto-incremented. This auto-increment is independent of other sprite registers.
 
Used to upload sprite patterns. Sprite patterns are 16x16 (256 bytes for 8 bit colour and 128 bytes for 4 bit colour sprites) and are sent in English reading order. Each byte is the offset, 0-255 (or two 0-15 for 4-bit graphics), within the active sprite palette. After sending 256 bytes, the target pattern slot is auto-incremented. This auto-increment is independent of other sprite registers.

Latest revision as of 11:49, 4 May 2020

Number $xx5B
Decimal 91
Short desc. Used to upload the pattern of the selected sprite.
Bit Mask %---- ---- 0101 1011 ??
Readable No
Writable Yes
Subsystem Sprites

Used to upload sprite patterns. Sprite patterns are 16x16 (256 bytes for 8 bit colour and 128 bytes for 4 bit colour sprites) and are sent in English reading order. Each byte is the offset, 0-255 (or two 0-15 for 4-bit graphics), within the active sprite palette. After sending 256 bytes, the target pattern slot is auto-incremented. This auto-increment is independent of other sprite registers.

Auto-increment from pattern slot 63 will wrap to slot 0 (only 64 pattern slots will be available in foreseeable future, and if ever extended, there will be separate configuration bit to enable more than 64 pattern slots).

With 4 bit sprites each pattern slot contains effectively two patterns, each 128 bytes long, the sub-pattern displayed is selected by "N6" bit in 5th sprite-attribute byte.

With 4 bit graphics the top bits (of each pattern byte) 7-4 are "left" pixel on display and bits 3-0 are "right next to it" pixel on display (in default mode, no mirror, no rotate).