Difference between revisions of "Sprite port-mirror Attribute 4 (with INC) Register"

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(Core 2.00.26 changes)
(Core 2.00.27 (or 28) changes to relative sprite system.)
Line 6: Line 6:
 
}}
 
}}
 
Byte 5 is bitmapped:
 
Byte 5 is bitmapped:
 +
:For '''anchor''' sprites:
 
{|class="wikitable"
 
{|class="wikitable"
 
! Bit !! Description
 
! Bit !! Description
 
|-
 
|-
−
| 7 || If 1, the pattern will be treated as 4-bit colour one (128 bytes), 0 is for 8-bit colour patterns (256 bytes)
+
| 7-6 || "H N6" - "H" is 4/8 bit graphics selector, "N6" is sub-pattern selector for 4 bit modes.<br />
 +
%00 = 8-bit colour patterns (256 bytes), this sprite is "'''anchor'''"<br />
 +
%01 = this sprite is "'''relative'''" (4/8-bit colour is selected by "anchor" sprite) → see tables below<br />
 +
%10 = 4-bit colour pattern (128 bytes) using bytes 0..127 of pattern slot, this sprite is "'''anchor'''"<br />
 +
%11 = 4-bit colour pattern (128 bytes) using bytes 128..255 of pattern slot, this sprite is "'''anchor'''"
 
|-
 
|-
−
| 6 || (if bit 7 = 1): Chooses top/bottom part of pattern slot when 4-bit colour pattern
+
| 5 || Type for following '''relative''' sprites: 0 = "composite", 1 = "big sprite"
−
0 will target bytes 0..127 of pattern "Name" (byte 4), 1 will target bytes 128..255 of pattern "Name".
 
−
 
 
−
(if bit 7 = 0): make this sprite "relative" one: 1 = relative, 0 = normal (anchor) type
 
 
|-
 
|-
−
| 5 || (if bit 7-6 = %01) for "relative" sprite, this bit chooses top/bottom part of pattern slot for 4-bit colour mode (4 or 8 bit mode is set by anchor sprite, relative sprite can't switch the colour mode). See Bit 6 description above, if anchor sprite is in 4-bit mode. If anchor sprite is in 8-bit mode, use always 0
+
| 4-3 || x-axis scale factor: %00 = 1x (16 pixels), %01 = 2x, %10 = 4x, %11 = 8x (128 pixels)
−
(else) For normal (anchor) sprites this is reserved, use always 0
+
|-
 +
| 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:
 +
{|class="wikitable"
 +
! 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)
 
| 4-3 || x-axis scale factor: %00 = 1x (16 pixels), %01 = 2x, %10 = 4x, %11 = 8x (128 pixels)
Line 23: Line 36:
 
| 2-1 || y-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
+
| 0 || Enable relative pattern offset (1 = Pattern index is added to anchor pattern index, 0 = independent pattern index)
 +
|}
 +
:For '''big-sprite relative''' sprites:
 +
{|class="wikitable"
 +
! 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)
 
|}
 
|}
  

Revision as of 02:18, 11 February 2019

Number $79
Readable No
Writable Yes
Short Description Same as Sprite port-mirror Attribute 4 Register ($39) (write fifth byte of sprite-attributes), plus increments Sprite port-mirror Index Register ($34)

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"
%01 = this sprite is "relative" (4/8-bit colour is selected by "anchor" sprite) → see tables below
%10 = 4-bit colour pattern (128 bytes) using bytes 0..127 of pattern slot, this sprite is "anchor"
%11 = 4-bit colour pattern (128 bytes) using bytes 128..255 of pattern slot, 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 Sprite Attribute Upload ($xx57 / 87) for extra notes about anchor/relative sprites, coordinates and clipping.

After write into sprite-attribute "byte 5" (Sprite Attribute Upload ($xx57 / 87)), the Sprite port-mirror Index Register ($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.

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