53251



     (R) Missile 2 to playfield collision.

53251          D003           HPOSP3
     (W) Horizontal position of player 3.

                              M3PF
     (R) Missile 3 to playfield collision.

53252          D004           HPOSM0
     (W) Horizontal position of missile 0. Missiles move horizontally like
     players. See the note in 53248 ($D000) concerning the use of
     horizontal registers.

                              P0PF
     (R) Player 0 to playfield collisions. There are some problems using
     collision detection in graphics modes nine to eleven. There are no
     obviously recognized collisions in GR.9 and GR.11. In GR.10
     collisions work only for the playfield colors that correspond to the
     usual playfield registers. Also, the background (BAK) color is set
     by PCOLR0 (location 704; $2C0) rather than the usual COLOR4
     (location 712; $2C8), which will affect the priority detection. In
     GR.10, playfield colors set by PCOLR0 to PCOLR3 (704 to 707;
     $2C0 to $2C3) behave like players where priority is concerned. Bit
     use is:

                Bit     7    6    5    4    3    2    1    0
          Playfield     .....unused.....    3    2    1    0
          Decimal       ................    8    4    2    1

53253          D005           HPOSM1
     (W) Horizontal position of missile 1.

                              P1PF
     (R) Player 1 to playfield collisions.

53254          D006           HPOSM2
     (W) Horizonal position of missile 2.

                              P2PF
     (R) Player 2 to playfield collisions.

53255          D007           HPOSM3
     (W) Horizontal position of missile 3.

                              P3PF
     (R) Player 3 to playfield collisions.

53256          D008           SIZEP0
     (W) Size of player 0. POKE with zero or two for normal size (eight
     color clocks wide), POKE with one to double a player's width
     (sixteen color clocks wide), and POKE with three for quadruple
     width (32 color clocks wide). Each player can have its own width set.