OS_SpriteOp 29 (changes)
Showing changes from revision #1 to #2:
Added | Removed | Changed
Programmer's OS Reference SWI Manuals Calls
» Part OS_SpriteOp 15 – SWI Calls
» OS_SpriteOp 29 – Create maskOS
» OS_SpriteOp
» OS_SpriteOp 29 – Create mask
OS_SpriteOp 29 – Create mask
(SWI &2E)
| Entry | |
|---|---|
| R0 | 29 (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) |
| Exit | |
|---|---|
| All other registers preserved | |
Use
This call allows a mask to be added to a sprite. If the sprite mode word has the top bit set (the wide mask flag) then an 8bpp alpha mask will be created, otherwise a standard binary mask will be created.
The new mask will be filled with a default value such that all pixels are 100% opaque (i.e. all mask pixels set to 255 for alpha masks, or 1 for binary masks)
Notes
If the sprite already has a mask, its contents will be erased, just as if a fresh mask had been created.
If you wish to convert between different mask formats, or to transfer data to/from an alpha channel, use OS_SpriteOp 38.
See also
Social
Follow us on
and
and
ROOL Store
Buy RISC OS Open merchandise here, including SD cards for Raspberry Pi and more.