Difference between revisions of "Clip Window Sprites Register"

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(added example of maximum clip window in the over-border case.)
m (extra bit of info from forums)
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The values are 0,255,0,191 after a Reset.
 
The values are 0,255,0,191 after a Reset.
  
Clip window on Sprites works by default only when the "draw over border" is disabled. With "over border" enabled, the clip window must be enabled extra by bit 5 in {{NextRegNo|$15}}, and X-axis coordinates of clip-window are then doubled, see the {{NextRegNo|$15}} for details and example. Set it to {0,159,0,255} to cover whole pixel+border sprite area (320x256 pixels area of display) in the x-axis doubled mode.
+
Clip window on Sprites works by default only when the "draw over border" is disabled. With "over border" enabled, the clip window must be enabled extra by bit 5 in {{NextRegNo|$15}}, and X-axis coordinates of clip-window are then doubled, see the {{NextRegNo|$15}} for details and example. Set it to {0,159,0,255} to cover whole pixel+border sprite area (320x256 pixels area of display) in the x-axis doubled mode. Although setting it larger (like {0,255,0,255}) should be safe operation and still the full 320x256 area for sprite pixels will be visible.
  
 
The current read/write index (which coordinate is next) can be read or reset by {{NextRegNo|$1C}}.
 
The current read/write index (which coordinate is next) can be read or reset by {{NextRegNo|$1C}}.

Revision as of 13:25, 1 January 2019

Number $19
Readable Yes
Writable Yes
Short Description Sets and reads clip-window for Sprites
  1. read/write: X1 position
  2. read/write: X2 position
  3. read/write: Y1 position
  4. read/write: Y2 position

The values are 0,255,0,191 after a Reset.

Clip window on Sprites works by default only when the "draw over border" is disabled. With "over border" enabled, the clip window must be enabled extra by bit 5 in Sprite and Layers System Register ($15), and X-axis coordinates of clip-window are then doubled, see the Sprite and Layers System Register ($15) for details and example. Set it to {0,159,0,255} to cover whole pixel+border sprite area (320x256 pixels area of display) in the x-axis doubled mode. Although setting it larger (like {0,255,0,255}) should be safe operation and still the full 320x256 area for sprite pixels will be visible.

The current read/write index (which coordinate is next) can be read or reset by Clip Window Control Register ($1C).