Nintendo 1504166 - Game Boy Advance SP Edition Console Programming Manual page 64

AGB Programming Manual
[d11-10] OBJ Mode
Specifies whether an OBJ is a normal OBJ or a semitransparent OBJ.
A normal OBJ is specified by 00, a semi-transparent OBJ by 01, and an
OBJ window by 10.
A value of 11 is a prohibited code, so care should be taken to prevent this
setting.
When a semi-transparent OBJ is specified, color special effects
processing can be performed. For information on color special effects,
see "9 Color Special Effects".
OBJs for which an OBJ window specification is used are not displayed as
normal OBJs; dots with non-zero character data are used as the OBJ
window.
[d09] Rotation/Scaling Double-Size Flag
OBJs are limited in size by the OBJ field (8x8 - 64x64 dots), and the
character data may surpass the boundaries of this field when rotated.
This problem can be avoided by implementing a pseudo double-size for
the OBJ field, by setting the double-size flag to 1.
With this setting, the OBJ does not surpass the boundaries of the OBJ
field even if the OBJ display is magnified by up to two-fold.
©1999 - 2001 Nintendo of America Inc.
64
Rendering Functions
D.C.N. AGB-06-0001-002B4