© 1985 ASCII CORP. / NIPPON GAKKI CO.
Page 100 of 108
© 2010-2015 Eugeny Brychkov
5.2. SPRITE MODE 2 (G3 … G7)
While there’s a room for 256 sprite patterns in sprite pattern generator table, VDP is
only capable of displaying 32 sprites (#0…#31) – limiting factor is sprite attribute table
which can hold attributes for 32
active
sprites only.
Up to 8 sprites can be displayed on a single horizontal line, and from the set of
displayed sprites on this line, the sprites with higher priority will be displayed, and the
overlapping portions of lower priority sprites will not be displayed. Lower sprite numbers
are assigned higher priority, with #0 is of highest priority and #31 is of lowest priority.
#0
#3
#4
#5
#7
#1
#2
#6
#8
When two sprites collide (their solid “1” portions have overlapped), status register’s
S#0 bit 5 “C” is set to 1, and the coordinates of the collision can be read from status
registers S#3 … S#5.
If there’re more than 8 sprites on the single horizontal line, bit 6 of the status register
S#0 “5S” is set to 1, and the lower order 5 bits of this status register S#0 will contain the
number of the ninth sprite.
The colors of the sprite are specified for each horizontal line.
The sprite priority may be cancelled by setting bit “CC” in the attribute table for
specific line of the sprite, and if sprites overlap, logical “OR” will be done on the colors of
the sprites. Therefore, while in sprite mode 1 sprites may only have two colors (color code
1 and transparent), in sprite mode 2 four colors may be displayed.
