Sprite DMA channels can be reused several times within the same display field. Thus,
you are not limited
to
having only eight sprites on the screen
at
the same time.
ABOUT
THIS
CHAPTER
This chapter discusses the following topics:
o Defining the size, shape, color, and screen position of sprites.
o Displaying and moving sprites.
o Combining sprites for more complex Images, additional width, or additional
colors.
o Reusing a sprite DMA channel multiple times within a display field
to
create
more than eight sprites on the screen
at
one time.
Forming
a
Sprite
To
form a sprite, you must first define it and then create a formal
data
structure
in
memory. You define a sprite by specifying its characteristics:
o On-screen
wid
th of up to
16
pixels.
o Unlimited height.
o Any shape.
o A combination of three colors, plus transparent.
o Any position on the screen.
'SCREEN
POSITION
A sprite's screen position is defined as a set of X,Y coordinates. Position (0,0), where
X
= 0 and Y = 0, is the upper left-hand corner of the display. You define a sprite's
location by specifying the coordinates of its upper left-hand pixel. Sprite position
is
always defined as though the display modes were low-resolution and non-interlaced.
The
X,Y coordinate system and definition of a sprite's position are graphically represented
in
92 Sprite Hardware
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