OS_SpriteOp 44 (changes)
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Programmer's OS Reference SWI Manuals Calls
» Part OS_SpriteOp 15 – SWI Calls
» OS_SpriteOp 44 – Write pixel maskOS
» OS_SpriteOp
» OS_SpriteOp 44 – Write pixel mask
OS_SpriteOp 44 – Write pixel mask
(SWI &2E)
| Entry | |
|---|---|
| R0 | 44 (Reason code) + Area value |
| R1 | Unused/Sprite area (as defined by area value in R0) |
| R2 | Sprite name/pointer (as defined by area value in R0) |
| R3 | X coordinate |
| R4 | Y coordinate |
| R5 | Mask value |
| Exit | |
|---|---|
| All registers preserved | |
Use
This call allows the value of a sprite mask pixel to be written.
Notes
Coordinates are specified in pixels, with (0,0) being the bottom-left corner of the sprite.
For sprites with the wide mask flag set in the Sprite Mode Word, the value in R5 should be an alpha value between 0 and 255, with 255 representing a fully opaque pixel and 0 representing a fully transparent pixel.
For other sprites, if R5 is zero the mask pixel will be set to zero (i.e. transparent), and if R5 is non-zero the mask pixel will be set to one (i.e. opaque).
An error will be returned if an attempt is made to use this operation on a sprite without a mask.
See also
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