The TIA (as seen by the programmer)
9.0 Object Priorities
Each object is assigned a priority so when any two objects
overlap the one with the highest priority will appear to
move in front of the other. To simplify hardware logic,
the missiles have the same priority as their associated
player, and the ball has the same priority as the
playfield. The background, of course, has the lowest
priority. The following table illustrates the normal
(default) priority assignments.
Priority Objects
1 P0, M0
2 P1, M1
3 BL, PF
4 BK
This priority assignment means that players and missiles
will move in front of the playfield. To make the players
and missiles move behind the playfield, a "1" must be
written to D2 of the CTRLPF register. The following table
illustrates how the priorities are affected:
Priority Objects
1 PF, BL
2 P0, M0
3 P1, M1
4 BK
One more priority control is available to be used for
displaying the score. When a "1" is written to D1 of the
CTRLPF register, the left half of the playfield takes on
the color of player 0, and the right half the color of
player 1. The game score can now be displayed using the PF
graphics register, and the score will be in the same color
as its associated player.