; Sneak Attack by David Plotkin
MODULE
BYTE
ChrBase=756,Max,Bkgrnd=710,
Fate=53770,Level=[1],CursIn=752,
Stick=632,Ps,Loud=[0],Indx=[0],
DownL=[0],DownR=[0],Loud1=[0],
Snd1=$D208,Snd2=$D20F,Freq=[169],
Wsync=$D40A,Colbk=$D018,
Nmien=$D40E,Hard=[15],
Consol=53279
CARD
Scrn=88,RamSet,HiMem=$2E5,
Score=[0],Comp=[300],Sdlst=560,
Vdslst=512
CARD ARRAY Linept(24)
BYTE ARRAY
Charset,Chopperstatus(30),
Chopperx(30),Choppery(30),
Expx(60),Expy(60),ExpStatus(60),
TrStatus(30),Trx(30),Try(30),
MisStatus(30),Misx(30),Misy(30),
Ll(20),Rr(20),Dlist,
ShapeTable(0)=
[254 16 124 71 127 12 62 0
127 8 62 226 254 24 126 0
96 96 48 48 24 60 231 255
24 24 24 24 24 60 231 255
6 6 12 12 24 60 231 255
128 85 17 66 24 170 91 131
60 126 255 255 195 66 36 24
60 36 24 255 60 24 36 102
0 0 0 0 0 0 0 0
60 36 24 255 60 24 36 102
60 36 219 255 60 24 36 102
60 60 24 60 60 24 24 28
60 60 24 60 60 60 102 195]
PROC Download()
;Step back HiMem and move the
;character set into RAM
CARD Index
BYTE Val
RamSet=(HiMem-$400)&$FC00
ChrBase=RamSet RSH 8
HiMem=RamSet
FOR Index=0 TO 1023 DO
Val=Peek(57344+Index)
Poke(RamSet+Index,Val)
OD
Charset=RamSet
RETURN
PROC Dlint()
;the display list interrupt routine
[$48 $8A $48 $98 $48]
Wsync=1
Colbk=50
[$68 $A8 $68 $AA $68 $40]
PROC ScoreLine()
;set up the dli
Dlist=Sdlst
Vdslst=Dlint
Dlist(27)=130
Nmien=$C0
RETURN
PROC Update()
;print score and level
Position(1,23)
Print("Score: ")
Position(8,23)
PrintC(Score)
Position(18,23)
Print("Level: ")
Position(25,23)
PrintB(Level)
RETURN
PROC Title()
BYTE colpf0=53270,colpf1=53271,
colpf2=53273,colpf3=53273,
rtclock=20,vcount=54283
Graphics(18)
Position(3,4)
PrintD(6,"SNEAK ATTACK")
Position(8,5)
PrintD(6,"BY")
Position(3,7)
PrintD(6,"david plotkin")
Position(3,9)
PrintD(6,"PRESS start")
WHILE Consol<>6 DO
colpf3=Fate
Wsync=0
colpf0=128-vcount+rtclock RSH 2
colpf1=vcount+rtclock RSH 2
OD
RETURN
PROC Gr0Init()
;Set up the address of each screen
;line and initialize
CARD xx
Graphics(0)
CursIn=1
Print(" ")
FOR xx=0 TO 23 DO
Linept(xx)=Scrn+(40*xx)
OD
FOR xx=0 TO 29 DO
Chopperstatus(xx)=0
Chopperx(xx)=0
Choppery(xx)=0
Misx(xx)=0
Misy(xx)=0
MisStatus(xx)=0
TrStatus(xx)=0
OD
FOR xx=0 TO 59 DO
ExpStatus(xx)=0
OD
FOR xx=0 TO 19 DO
Ll(xx)=0
Rr(xx)=0
OD
Bkgrnd=0
Update()
RETURN
PROC Plot0(BYTE x,y,ch)
;Plot a char at location x,y
BYTE ARRAY line
line=Linept(y)
line(x)=ch
RETURN
BYTE FUNC Locate0(BYTE x,y)
;Returns the value of the char at x,y
BYTE ARRAY line
line=Linept(y)
RETURN(line(x))
PROC Noise()
;the explosion noises
IF Loud=0 AND Loud1=0
AND Freq=169 THEN
RETURN
FI
IF Loud THEN
Loud==-2
Sound(0,90,8,Loud)
FI
IF Loud1 THEN
Loud1==-2
Sound(1,150,8,Loud1)
FI
IF Freq<168 THEN
Freq==+8
Sound(2,Freq,10,4)
ELSE
Freq=169
Sound(2,0,0,0)
FI
RETURN
PROC HitChute(BYTE wh)
;see which chute was hit by missile wh
BYTE lp
FOR lp=0 TO 29 DO
IF Misx(wh)=Trx(lp) AND
(Misy(wh)=Try(lp) OR
Misy(wh)=Try(lp)+1) THEN
TrStatus(lp)=2
Plot0(Trx(lp),Try(lp),0)
Plot0(Trx(lp),Try(lp)+1,10)
Plot0(Trx(lp),Try(lp)+2,0)
EXIT
FI
OD
IF Try(lp) LSH 3 < Freq THEN
Freq=Try(lp) LSH 3
FI
RETURN
PROC HitMan(BYTE wh)
;see which man was hit by missile wh
BYTE lp
FOR lp=0 TO 29 DO
IF Misx(wh)=Trx(lp) AND
(Misy(wh)=Try(lp)+1 OR
Misy(wh)=Try(lp)+2) THEN
TrStatus(lp)=3
Plot0(Trx(lp),Try(lp)+1,6)
Plot0(Trx(lp),Try(lp),0)
Plot0(Trx(lp),Try(lp)+2,0)
FI
OD
Loud1=12
RETURN
PROC ExplodeChopper(BYTE lp)
;explosions in place of Chopper lp
BYTE lq
FOR lq=0 TO 59 STEP 2 DO ;find empty
IF ExpStatus(lq)=0 THEN
ExpStatus(lq)=1
ExpStatus(lq+1)=1
Expx(lq)=Chopperx(lp)
Expx(lq+1)=Chopperx(lp)+1
Expy(lq)=Choppery(lp)
Expy(lq+1)=Choppery(lp)
Chopperstatus(lp)=0
Plot0(Expx(lq),Expy(lq),6)
Plot0(Expx(lq+1),Expy(lq+1),6)
EXIT
FI
OD
RETURN
PROC HitChopper(BYTE wh)
;which chopper was hit by missile wh
BYTE lp
FOR lp=0 TO 29 DO
IF Misy(wh)=Choppery(lp) AND
(Misx(wh)=Chopperx(lp) OR
Misx(wh)=Chopperx(lp)+1) THEN
ExplodeChopper(lp)
EXIT
FI
OD
Loud=12
RETURN
PROC MissileHit(BYTE wh)
;see if missile wh hit anything
BYTE dum
dum=Locate0(Misx(wh),Misy(wh))
IF dum=0 THEN
Plot0(Misx(wh),Misy(wh),84)
RETURN
FI
MisStatus(wh)=0
IF dum=1 OR dum=2 THEN
HitChopper(wh)
Score==+1
ELSEIF (dum=7 AND Indx<6 OR
dum=8 AND Indx>3) THEN
HitChute(wh)
Score==+2
ELSEIF (dum=8 AND Indx<4 OR
dum=9 AND Indx>1) THEN
HitMan(wh)
Score==+1
FI
RETURN
PROC Modify()
;Modify the RAM character set
CARD xx
FOR xx=0 TO 103 DO
Charset(xx+8)=ShapeTable(xx)
OD
RETURN
PROC LaunchTrooper(BYTE wh)
;drop a paratrooper from chopper wh
BYTE lp
IF Fate>240-(Level LSH 1) THEN
FOR lp=0 TO 29 DO ;find MT trooper
IF TrStatus(lp)=0 THEN ;got one
TrStatus(lp)=1
Trx(lp)=Chopperx(wh)
IF Trx(lp)=0 THEN
Trx(lp)=1
FI
Try(lp)=Choppery(wh)+1
Plot0(Trx(lp),Try(lp),7)
Plot0(Trx(lp),Try(lp)+1,8)
Plot0(Trx(lp),Try(lp)+2,9)
EXIT
FI
OD
FI
RETURN
PROC EraseChopper(BYTE wh)
;erase chopper number wh
Plot0(Chopperx(wh),Choppery(wh),0)
Plot0(Chopperx(wh)+1,Choppery(wh),0)
Chopperstatus(wh)=0
Chopperx(wh)=0
Choppery(wh)=0
RETURN
PROC DrawChopper(BYTE wh)
;draw chopper number wh
Plot0(Chopperx(wh),Choppery(wh),1)
Plot0(Chopperx(wh)+1,Choppery(wh),2)
RETURN
PROC ClearScreen()
;clear the screen
BYTE lp
FOR lp=0 TO 29
DO
IF Chopperstatus(lp) THEN
EraseChopper(lp)
FI
IF TrStatus(lp) THEN
TrStatus(lp)=0
Plot0(Trx(lp),Try(lp),0)
Plot0(Trx(lp),Try(lp)+1,0)
Plot0(Trx(lp),Try(lp)+2,0)
FI
IF MisStatus(lp)=1 THEN
MisStatus(lp)=0
Plot0(Misx(lp),Misy(lp),0)
FI
OD
FOR lp=0 TO 59 STEP 2 DO
IF ExpStatus(lp)=1 THEN
ExpStatus(lp)=0
ExpStatus(lp+1)=0
Plot0(Expx(lp),Expy(lp),0)
Plot0(Expx(lp+1),Expy(lp+1),0)
FI
OD
RETURN
PROC MoveChopper()
;move the choppers
BYTE lp,ps=[0]
FOR lp=0 TO 29 DO
IF Chopperstatus(lp)=1 THEN ;right
IF Chopperx(lp)=38 THEN
EraseChopper(lp)
ELSE
Plot0(Chopperx(lp),
Choppery(lp),0)
Chopperx(lp)==+1
DrawChopper(lp)
LaunchTrooper(lp)
FI
FI
IF Chopperstatus(lp)=2 THEN ;left
IF Chopperx(lp)=0 THEN
EraseChopper(lp)
ELSE
Plot0(Chopperx(lp)+1,
Choppery(lp),0)
Chopperx(lp)==-1
DrawChopper(lp)
LaunchTrooper(lp)
FI
FI
OD
IF ps=0 THEN
Charset(8)=56
Charset(16)=28
ps=1
ELSE
ps=0
Charset(8)=254
Charset(16)=127
FI
RETURN
PROC LaunchChopper()
;Decide whether to send off a new
;chopper, which side, how high up
BYTE lp
IF Fate>230-(Level LSH 1) THEN
FOR lp=0 TO 29 DO ;find MT chopper
IF Chopperstatus(lp)=0 THEN
Choppery(lp)=Rand(Hard)
IF Fate>128 THEN
Chopperx(lp)=38 ;right side
Chopperstatus(lp)=2
ELSE
Chopperx(lp)=0 ;left side
Chopperstatus(lp)=1
FI
DrawChopper(lp)
EXIT
FI
OD
FI
RETURN
PROC DrawBase()
;draw the base
BYTE lp
FOR lp=19 TO 21 DO
Plot0(lp,22,128)
OD
Plot0(20,21,4)
RETURN
PROC AimGun()
;read the joystick and move the base
IF Stick=11 THEN
Ps=3
ELSEIF Stick=7 THEN
Ps=5
ELSE
Ps=4
FI
Plot0(20,21,Ps)
RETURN
PROC Shoot()
;send off a bullet
BYTE trig=644,lp,flg=[0]
IF trig=1 OR flg=0 THEN
flg=1
RETURN
FI
FOR lp=0 TO 29 DO ;find empty shot
IF MisStatus(lp)=0 THEN ;got one
MisStatus(lp)=1
Misy(lp)=20
IF Ps=3 THEN
Misx(lp)=19
ELSEIF Ps=5 THEN
Misx(lp)=21
ELSE
Misx(lp)=20
FI
MissileHit(lp)
EXIT
FI
OD
flg=0
RETURN
PROC MoveShots()
;move the fired bullets
BYTE lp
FOR lp=0 TO 29 DO ;for each shot
IF MisStatus(lp)=1 THEN
Plot0(Misx(lp),Misy(lp),0)
IF Stick=11 THEN
Misx(lp)==-1
ELSEIF Stick=7 THEN
Misx(lp)==+1
ELSE
Misy(lp)==-1
FI
IF (Misx(lp)<>39 AND
Misy(lp)<>255 AND
Misx(lp)<>0) THEN
MissileHit(lp)
ELSE
MisStatus(lp)=0
FI
FI
OD
RETURN
PROC MoveExplosions()
;move the explosions
BYTE lp
FOR lp=0 TO 59 STEP 2 DO
IF ExpStatus(lp)=1 THEN
Plot0(Expx(lp),Expy(lp),0)
Plot0(Expx(lp+1),Expy(lp+1),0)
Expy(lp)==+1
Expy(lp+1)==+1
Expx(lp)==-1
Expx(lp+1)==+1
IF Expy(lp)<>22 AND Expx(lp)<>0
AND Expx(lp+1)<>39 THEN
Plot0(Expx(lp),Expy(lp),6)
Plot0(Expx(lp+1),Expy(lp+1),6)
ELSE
ExpStatus(lp)=0
ExpStatus(lp+1)=0
FI
FI
OD
RETURN
PROC BaseExplode()
;explode the base
BYTE ARRAY endx(0)=[16 24 17 23 20],
endy(0)=[22 22 19 19 17]
BYTE lp,time=20
color=38
FOR lp=0 TO 4 DO
Plot(20,22)
DrawTo(endx(lp),endy(lp))
OD
FOR lp=0 TO 16 DO
Sound(0,Fate,8,16-lp)
Sound(1,Fate,8,16-lp)
time=0
DO
UNTIL time=15
OD
OD
SndRst()
color=32
FOR lp=0 TO 4 DO
Plot(20,22)
DrawTo(endx(lp),endy(lp))
OD
RETURN
PROC EndRight()
;move the troopers from the right
;to the base
BYTE lp,lq,nn,time=20
FOR lp=0 TO 19 DO
IF Rr(lp)=1 THEN
lq=21+lp
WHILE lq>20 DO
IF nn=12 THEN
nn=13
ELSE
nn=12
FI
Plot0(lq,22,nn)
time=0
DO
UNTIL time=10
OD
Plot0(lq,22,0)
lq==-1
OD
Plot0(21,22,11)
FI
OD
FOR lp=0 TO 3 DO
Plot0(21,22-lp,11)
time=0
DO
UNTIL time=10
OD
OD
BaseExplode()
RETURN
PROC EndLeft()
;Move the troopers from the left to
;the base
BYTE lp,lq,lc,nn,time=20
FOR lp=0 TO 19 DO
lq=19-lp
IF Ll(lq)=1 THEN
FOR lc=lq TO 19 DO
IF nn=12 THEN
nn=13
ELSE
nn=12
FI
Plot0(lc,22,nn)
time=0
DO
UNTIL time=10
OD
Plot0(lc,22,0)
OD
Plot0(19,22,11)
FI
OD
FOR lp=0 TO 3 DO
Plot0(19,22-lp,11)
time=0
DO
UNTIL time=10
OD
OD
BaseExplode()
RETURN
PROC EndPrint()
;print the end of game message and
;test for new game
BYTE trig=644,lp
Position(10,7)
Print("Game Over...Final Score:")
Position(15,8)
PrintC(Score)
Position(15,9)
Print("FINAL LEVEL :")
PrintB(Level)
Position(10,20)
Print("Press FIRE to play again")
DO
UNTIL trig=0
OD
DownL=0
DownR=0
Put(125)
FOR lp=0 TO 19 DO
Ll(lp)=0
Rr(lp)=0
OD
Score=0
Level=1
DrawBase()
Update()
Hard=15
RETURN
PROC GameOverTwo()
;game over when four troopers down
BYTE lp
SndRst()
ClearScreen()
Loud=0
Loud1=0
Freq=169
FOR lp=0 TO 19 DO
IF Ll(lp)=1 THEN
Plot0(lp,22,11)
FI
IF Rr(lp)=1 THEN
Plot0(lp+21,22,11)
FI
OD
IF DownL=4 THEN
EndLeft()
ELSE
EndRight()
FI
EndPrint()
RETURN
PROC GameOverOne()
;game over when trooper lands on base
BYTE lp
SndRst()
ClearScreen()
Loud=0
Loud1=0
Freq=169
FOR lp=0 TO 19 DO
IF Ll(lp)=1 THEN
Plot0(lp,22,11)
FI
IF Rr(lp)=1 THEN
Plot0(lp+21,22,11)
FI
OD
BaseExplode()
EndPrint()
RETURN
PROC TrooperDown(BYTE wh)
;redraw trooper wh at bottom of screen
BYTE cc
TrStatus(wh)=0
cc=Trx(wh)
Plot0(Trx(wh),Try(wh),0) ;erase chute
Plot0(Trx(wh),Try(wh)+1,11) ;replace
IF Trx(wh)<20 AND Ll(cc)=0 THEN
Ll(cc)=1
DownL==+1
ELSEIF Trx(wh)>20 AND
Rr(cc-21)=0 THEN
Rr(cc-21)=1
DownR==+1
ELSEIF Trx(wh)=20 THEN
GameOverOne()
FI
IF DownL=4 OR DownR=4 THEN
GameOverTwo()
FI
RETURN
PROC TrooperFall()
;make trooper fall when chute hit
BYTE lp,qq,cc
FOR lp=0 TO 29 DO
IF TrStatus(lp)=2 THEN
Plot0(Trx(lp),Try(lp)+1,0)
Try(lp)==+1
IF Try(lp)=21 THEN
cc=Trx(lp)
IF Trx(lp)<20 AND Ll(cc)=1 THEN
DownL==-1
Ll(cc)=0
ELSEIF Trx(lp)>20 AND
Rr(cc-21)=1 THEN
Rr(cc-21)=0
DownR==-1
FI
FI
IF (Try(lp)<22 AND Trx(lp)<>20)
OR (Try(lp)<20 AND
Trx(lp)=20) THEN
Plot0(Trx(lp),Try(lp)+1,10)
ELSE
TrStatus(lp)=0
FI
FI
OD
RETURN
PROC MoveTroopers()
;move paratroopers down screen
BYTE lp,qq
BYTE ARRAY Trooper(0)=
[60 126 255 255 195 66 36 24
60 36 24 255 60 24 36 102
0 0 0 0 0 0 0 0]
FOR lp=0 TO Indx DO
Charset(56+lp)=0
OD
MoveBlock(Charset+56+Indx+1,
Trooper,16)
Indx==+1
IF Indx<8 THEN
RETURN
FI
Indx=0
FOR lp=0 TO 29 DO
IF TrStatus(lp)=1 THEN
Plot0(Trx(lp),Try(lp),0)
Try(lp)==+1
IF Try(lp)=21 THEN
TrooperDown(lp)
FI
FI
IF TrStatus(lp)=3 THEN
TrStatus(lp)=0
Plot0(Trx(lp),Try(lp)+1,0)
FI
OD
MoveBlock(Charset+56,Trooper,24)
FOR lp=0 TO 29 DO
IF TrStatus(lp)=1 THEN
Plot0(Trx(lp),Try(lp),7)
Plot0(Trx(lp),Try(lp)+1,8)
Plot0(Trx(lp),Try(lp)+2,9)
FI
OD
RETURN
PROC NewLevel()
;go to higher level
BYTE lp,time=20
Level==+1
IF Level>100 THEN
Level=100
FI
SndRst()
Loud=0
Loud1=0
Freq=169
Comp==+300
FOR lp=10 TO 150 STEP 10 DO
Sound(0,lp,10,4)
Sound(1,lp+10,10,4)
time=0
DO
UNTIL time=2
OD
OD
Position(25,23)
PrintB(Level)
IF Level>8 THEN
Hard=19
FI
SndRst()
RETURN
PROC Main()
BYTE time=20,lp,ch=764
Title()
Gr0Init()
Snd1=0
Snd2=3
Download()
Modify()
DrawBase()
ScoreLine()
DO
LaunchChopper()
MoveChopper()
MoveExplosions()
Noise()
TrooperFall()
MoveTroopers()
Position(8,23)
PrintC(Score)
IF Score>Comp THEN
NewLevel()
FI
time=0
FOR lp=2 TO 6 STEP 2 DO
AimGun()
Shoot()
MoveShots()
DO
UNTIL time=lp
OD
OD
OD
RETURN