Clip Window Sprites Register: Difference between revisions
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 | TBRegisterNumber::$19 |
|---|---|
| Readable | TBRegisterReadable::Yes |
| Writable | TBRegisterWritable::Yes |
| Short Description | ShortDesc::Sets and reads clip-window for Sprites |
- read/write: X1 position
- read/write: X2 position
- read/write: Y1 position
- 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 {{#ask: TBRegisterNumber::$15 }} ($15), and X-axis coordinates of clip-window are then doubled, see the {{#ask: TBRegisterNumber::$15 }} ($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 {{#ask: TBRegisterNumber::$1C }} ($1C).