Figure 16 - Rotation/Scaling Background Screen Sizes - Nintendo GAME BOY ADVANCE Programming Manual

28
(2) Illustration of Screen Sizes for Rotation/Scaling BG Screens

Figure 16 - Rotation/Scaling Background Screen Sizes

[d15,d14]=[0,0]
Virtual screen size: 128 x 128
SC0
(128 x 128)
Display Screen
(240 x 160)
[d15,d14]=[1,0]
Virtual screen size: 512 x 512
SC0
(512 x 512)
Display Screen
(240 x 160)
SC0
or
Transparent
BG2CNT,BG3CNT [d13] Area Overflow Processing
When the display screen overflows the boundaries of the virtual screen due to a rotation/scaling oper-
ation, this bit can be used to choose whether the area of the screen into which the overflow occurs is
displayed as transparent or wraps around the display screen.
For information on scaling, see
BG*CNT [d12-08] Screen Base Block Specification
Specifies the starting block in VRAM where screen data are stored.
(32 steps: 0-31; 2-KB increments).
See "6.1.3 VRAM Address Mapping of BG
BG*CNT [d07] Color Mode
Specifies whether to reference BG character data in 16 color x 16 palette format or 256 color x 1 pal-
ette format.
BG*CNT [d06] Mosaic
Turns mosaic processing for BG on and off.
AGB-06-0001-002-B13
Released: May 27, 2005
Game Boy Advance Programming Manual
SC0
or
Transparent
SC0
or
Transparent
SC0
or
Transparent
"6.1.7 BG Rotation and Scaling
Data" on page 30.
[d15,d14]=[0,1]
Virtual screen size: 256 x 256
SC0
SC0
or
(256 x 256)
Transparent
Display Screen
(240 x 160)
SC0 SC0
or or
Transparent Transparent
[d15,d14]=[1,1]
Virtual screen size: 1024 x1024
SC0
(1024 x
1024)
Display Screen
(240 x 160)
SC0
or
Transparent
Features" on page 40.
© 1999-2005 NINTENDO
May 25, 2005
SC0
or
Transparent
SC0
or
Transparent