53261



     60  NEXT X
     70  INPUT A,B: REM MISSILE SIZE AND S
        HAPES
     80  POKE 53260,A: POKE 53265,5
     100 GOTO 30

     Here's another example using DMA; GRACTL and DACTL
     (53277 and 54272; $D0lD and $D400):

     10  POKE 623,1: POKE 559,54: POKE 542
        79, 224: POKE 53277,1
     20  FOR N = 53252 TO 53255: POKE N, 1
        00 + X: X = X + 10: NEXT N: X = 0
     30  INPUT SIZE: POKE 53260, SIZE
     40  GOTO 30

     See 54279 ($D407) for more information on P/M graphics.

                              P0PL
     (R) Player 0 to player collisions. Bit use is:

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

53261          D00D           GRAFP0
     (W) Graphics shape for player 0 written directly to the player
     graphics register. In using these registers, you bypass ANTIC.
     You only use the GRAFP# registers when you are not using
     Direct Memory Access (DMA: see GRACTL at 53277). If DMA is
     enabled, then the graphics registers will be loaded automatically
     from the area specified by PMBASE (54279; $D407).

     The GRAF registers can only write a single byte to the playfield,
     but it runs the entire height of the screen. Try this to see:

     10  POKE 53248, 160: REM SET HORIZONT
        AL POSITION OF PLAYER 0
     20  POKE 704, 245: REM SET PLAYER 0 C
        OLOUR TO ORANGE
     30  POKE 53261, 203: REM BIT PATTERN
        11001011

     To remove it, POKE 53261 with zero. The bit order runs from
     seven to zero, left to right across the TV screen. Each bit set will
     appear as a vertical line on the screen. A value of 255 means all
     bits are set, creating a wide vertical line. You can also use the
     size registers to change the player width. Using the GRAF
     registers will allow you to use players and missiles for such things
     as boundaries on game or text fields quite easily.

                              P1PL