Table 17 - Specifications For The Bldcnt Register - Nintendo GAME BOY ADVANCE Programming Manual

68
In addition, semi-transparent OBJs are individually specified in OAM, and color special effects for the OBJ
as a whole, are specified in the BLDCNT register. These specifications are summarized in the following
table.
Table 17 - Specifications for the BLDCNT Register
BLDCNT
d07 d06
0 0 No special effects
0 1 blending (Semi-transpar-
α
ency processing)
1 0 Brightness Increase
1 1 Brightness Decrease
AGB-06-0001-002-B13
Released: May 27, 2005
Game Boy Advance Programming Manual
Type
Normally, color special effects processing is not per-
formed.
16-level semi-transparency processing (
performed only when a semi-transparent OBJ is
present and is followed immediately by a 2
screen.
If the 1
target screen, 16-level semi-transparency processing
( blending) is performed.
α
The bits of the backdrop of the 1
be turned off ([d05]=0).
When OBJ = 1 for the 1
executed for all OBJs regardless of the OBJ type.
When OBJ=0, processing is executed only if the OBJ
is semi-transparent.
Gradually increases brightness for 1
The entire screen can gradually be made whiter by
setting all bits of the specification for the 1st target
screen to 1.
When OBJ=1 for the 1st target screen, processing for
increased brightness is executed only for normal
objects.
If a semi-transparent OBJ is the 1st target screen,
blending processing is always executed.
Gradually decreases brightness for 1
The entire screen can gradually be made darker by
setting all bits of the specification for the 1st target
screen to 1.
When OBJ=1 for the 1st target screen, processing for
decreased brightness is executed only for normal
objects.
If a semi-transparent OBJ is the 1st target screen,
blending processing is always executed.
Color Special Effects Processing
st
target screen is followed immediately by a 2
st
st
target pixel, processing is
May 25, 2005
blending) is
α
nd
target
nd
target screen should
st
target screen.
α
st
target screen.
α
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