Dominic Land for the Atari 2600

rem Generated 02/11/2015 12:26:30 by Visual bB Version 1.0.0.548
 rem **********************************
 rem *<filename>                      *
 rem *<description>                   *
 rem *<author>                        *
 rem *<contact info>                  *
 rem *<license>                       *
 rem **********************************


 playfield:
 ................................
 XXX...X...X.X..X.X..X.X..XX.....
 X..X.X.X.X.X.X.X.XX.X.X.X.....X.
 X..X.X.X.X.X.X.X.X.XX.X.X....X.X
 XXX...X..X...X.X.X..X.X..XX...X.
 ................................
 ...X....X......XXX..X..X.XXX....
 ..X.X...X.....X...X.XX.X.X..X...
 ...X....X.....XXXXX.X.XX.X..X...
 ........XXXX..X...X.X..X.XXX....
 ................................
end

 COLUBK = $BC
 COLUPF = $BE
 ; COLUP0 = $3E
 ; COLUP1 = $3E

   dim _Sound0 = c
   dim _Chan0_Duration = x
   dim _C0 = e
   dim _V0 = f
   dim _F0 = g


 player0x=50:player0y=50
 player1x=20:player1y=20
 missile0height=4:missile0y=255
 NUSIZ0 = 16




sprites

 player0:
 %00111100
 %00011000
 %11111111
 %01111110
 %00111100
 %00111100
 %00011000
 %00011000
end

 player1:
 %00101010
 %01001001
 %00101010
 %00110110
 %01111111
 %01011101
 %01101011
 %00111110
end

 if missile0y>240 then goto skip
 missile0y=missile0y-2:goto draw_loop

skip
 if joy0fire then missile0y = player0y-2:missile0x = player0x+4:  _Sound0 = 4 : _Chan0_Duration = 12 :  _V0 = 8 : _F0 = 22
draw_loop
 drawscreen

 if player1y<player0y then player1y=player1y+1
 if player1y>player0y then player1y=player1y-1
 if player1x<player0x then player1x=player1x+1
 if player1x>player0x then player1x=player1x-1
 player1x=player1x:player1y=player1y

 if joy0up then player0y=player0y-1:goto jump
 if joy0down then player0y=player0y+1:goto jump
 if joy0left then player0x=player0x-1:goto jump
 if joy0right then player0x=player0x+1:goto jump

 if collision(missile0,player1) then score=score+1:player1x=rand/2:player1y=0:missile0y=255
 if collision(player0,player1) then score=score-1:player1x=rand/2:player1y=0:missile0y=255

jump

;***************************************************************
   ;
   ;  Channel 0 sound effect check.
   ;
   ;```````````````````````````````````````````````````````````````
   ;  If no channel 0 sound effect is on, skip all channel 0
   ;  sound effect subsections.
   ;
   if !_Sound0 then goto __Skip_Channel_0

   ;```````````````````````````````````````````````````````````````
   ;  Decreases the channel 0 duration counter.
   ;
   _Chan0_Duration = _Chan0_Duration - 1

   ;```````````````````````````````````````````````````````````````
   ;  If channel 0 duration counter is zero, end current sound
   ;  effect.
   ;
   if !_Chan0_Duration then goto __Clear_Channel_0




   ;***************************************************************
   ;
   ;  Channel 0 sound effect 4.
   ;
   ;  The volume and the frequency changes.
   ;
   ;```````````````````````````````````````````````````````````````
   ;  If sound 4 isn't on, skip this subsection.
   ;
   if _Sound0 <> 4 then goto __Skip_Chan0_Sound_004

   ;```````````````````````````````````````````````````````````````
   ;  Sets the tone, volume and frequency.
   ;
   AUDC0 = 4 : AUDV0 = _V0 : AUDF0 = _F0

   ;```````````````````````````````````````````````````````````````
   ;  Only looks at the even/odd bit.
   ;
   temp5 = _Chan0_Duration & %00000001

   ;```````````````````````````````````````````````````````````````
   ;  Decreases volume only when _Chan0_Duration is an odd number.
   ;
   if temp5 && _V0 then _V0 = _V0 - 1

   ;```````````````````````````````````````````````````````````````
   ;  Decreases the frequency variable.
   ; DM edited this to decend through the pitches - strangely by changing - to +
   if _F0 then _F0 = _F0 + 1

   ;```````````````````````````````````````````````````````````````
   ;  Jumps to end of channel 0 area.
   ;
   goto __Skip_Channel_0

__Skip_Chan0_Sound_004



   ;***************************************************************
   ;
   ;  Channel 0 sound effect 5.
   ;
   ;  The tone, volume, and frequency changes.
   ;
   ;```````````````````````````````````````````````````````````````
   ;  If sound 5 isn't on, skip this subsection.
   ;
   if _Sound0 <> 5 then goto __Skip_Chan0_Sound_005

   ;```````````````````````````````````````````````````````````````
   ;  Sets the tone, volume and frequency.
   ;
   AUDC0 = _C0 : AUDV0 = _V0 : AUDF0 = _F0

   ;```````````````````````````````````````````````````````````````
   ;  Flips the tone between 4 and 12.
   ;
   _C0 = _C0 ^ 8

   ;```````````````````````````````````````````````````````````````
   ;  Only looks at the even/odd bit.
   ;
   temp5 = _Chan0_Duration & %00000001

   ;```````````````````````````````````````````````````````````````
   ;  Decreases volume only when _Chan0_Duration is an odd number.
   ;
   if temp5 && _V0 then _V0 = _V0 - 1

   ;```````````````````````````````````````````````````````````````
   ;  Decreases the frequency variable.
   ;
   if _F0 then _F0 = _F0 - 1

   ;```````````````````````````````````````````````````````````````
   ;  Jumps to end of channel 0 area.
   ;
   goto __Skip_Channel_0

__Skip_Chan0_Sound_005



   ;***************************************************************
   ;
   ;  Other channel 0 sound effects go here.
   ;
   ;***************************************************************



   ;***************************************************************
   ;
   ;  Jumps to end of channel 0 area. (This catches any mistakes.)
   ;
   goto __Skip_Channel_0



   ;***************************************************************
   ;
   ;  Clears channel 0.
   ;
__Clear_Channel_0

   ;```````````````````````````````````````````````````````````````
   ;  Turns off channel 0 sound variable and mutes channel.
   ;
   _Sound0 = 0 : AUDV0 = 0



   ;***************************************************************
   ;
   ;  End of channel 0 area.
   ;
__Skip_Channel_0

 goto sprites