Atari XL User Manual

CHAPTER 15
PLAYER-MISSILE GRAPHICS
The 16 graphics modes of the XL allow you to
create superb displays, but there is one thing
missing; it is very difficult to produce animated
displays using the normal graphics facilities. The
Atari has a second kind of graphics feature to
overcome this problem: player-missile graphics.
Consider the problems of producing an animated
display, even if you have only one object moving
over a fixed background. As well as redrawing the
moving object every time its position changes, you
must redraw the background, or the moving object
will leave a trail of damage in its wake. Atari have
solved this problem by providing movable graphics
objects - called players and missiles, which can
easily be moved across the screen without any risk
of upsetting the background image.
Players and missiles are similar in nature. A
player can extend over the full height of the screen
and be up to eight pixels wide; a missile is the same
height but only two pixels wide. Four players and
four missiles are available, or the missiles may be
combined and used as a fifth player. The players
and missiles are completely independent of the
background display, and can be used in conjunction
with displays in any of the XL's graphics modes.
A
further feature, which is useful in many
applications, is that the Atari hardware (the GTIA
chip) automatically detects the 'col lisions' between
pairs of players, players and missiles, and players
or missiles and background features when they are
overlapping each other on the display. You can in
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Atari XL Specifications

General

Brand	Atari
Model	XL
Category	Desktop
Language	English