A.N.A.L.O.G. ISSUE 27 / FEBRUARY 1985 / PAGE 43

24K Cassette or 32K Disk

Way back in the golden days, when issues of **ANALOG
Computing** were still numbering in the teens,
I wrote a program called Bounce. It appeared in the
Our Game column in issue 15. At that time, I was
fiddling with a fun new language for the Atari—Action!
by Optimized Systems Software. I was thinking
that a version of Bounce in Action! would be
a worthwhile project.

Not long after I had that thought I discovered, to
my amusement, that someone had beaten me to it.
The friendly folks at **ANALOG Computing** told me
one day that a certain David Plotkin had submitted
a little ditty called Bounce in Action!, which later
appeared in issue 20.

However, David’s idea of a better Bounce program
was different from mine. His improvements consisted
of adding GTIA color and, of course, speed (with
Action!) to the original design. I *enjoyed* playing with
David’s program, and I was *pleased* that someone else
was as enthusiastic about Bounce as I was…I simply
had another idea that had to be tried.

To me, the next natural step for Bounce is to add more discs—having multiple moving objects at your command makes Bounce about a million times more fun than the original. Of course, Action! is the only high-level language for the Atari that is fast enough to do a multiple-object Bounce effectively.

First there was Bounce, then Bounce in Action!, now I give you More Fun with Bounce (MFB for short).

I had other upgrading in mind, too. Tops on the list was user-friendliness. MFB lets you move the cursor around freely without upsetting the walls or the discs already laid down. Drawing or erasing occurs only when your joystick trigger is held down. To switch between the two functions (drawing and erasing), simply hit the SPACE BAR.

Another user-friendly feature is the amount of control over cursor speed available. For a slow cursor (to maintain fine drawing control), hit a lower digit key like 3 or 4. For high-speed drawing, hit 7 or 8. Cursor speed 9 is for maniacs only.

Laying down the spheres is simplicity itself. Just hit the B key. A disc appears at the cursor’s position, while the cursor itself moves to the right (so you can keep laying down more). Note that—when drawing, erasing, moving or placing balls—the cursor performs automatic wraparound should it go off the edge of the screen.

Even Bounce’s screen-clearing feature has been improved upon. In MFB, when you hit ESC, instead of the whole screen clearing, only the discs disappear. This lets you keep your old wall patterns. If you’d like to clear everything, just hit CTRL-ESC. To remove individual discs, draw or erase over them with the cursor.

To start things bouncing, hit START. (If you forgot to lay discs down, the program automatically returns you to the drawing mode.) Immediately, the playing field fills with red goop (to be eaten away by the bouncing balls), and the number of objects bouncing appears in the text window.

Again, as in drawing mode, you have a number of options. For starters, you have complete control over disc speed. Simply hit digit keys 0 through 9, 9 being the fastest. Keep in mind, however, that the fewer objects you have on screen, the faster they will go (this is a natural by-product of the limited processing speed of your Atari computer). One or two discs on the screen at speed 9 move so fast that they are more of a blur than an object.

You may notice as the balls are bouncing that only one of them is actually making bouncing sounds; the others are silent. To change the “sound focus,” hit the S key. This allows you to make different balls audible, one at a time. If you keep hitting S, you’ll finally return sound focus to the original disc. This effect is easier to see if you have only a few objects on the screen.

An improvement I’ve always wanted to add to Bounce is to give the user some direct control over the bouncing sphere. In MFB, this feature exists and is called “nudging.” When you hit the N key, the ball that the sound focus is on gets nudged. The effect of this is distinct, yet simple—it causes the ball to react as if a vertical wall were momentarily placed directly ahead of it. Essentially, the ball bounces off of a ghost wall.

Nudging is fun (as is holding down the N key for repeated nudgings) and, also, useful if there is a red area on the screen where no ball has been. You can direct one over to that area by nudging it. Note: it is best to practice nudging with only a few objects and at a slow speed. Also note: you can nudge different spheres by changing the sound focus.

When you want to change your wall configuration or the number of bouncing objects, hit SELECT to get back to the drawing mode. To start with a fresh screen, just hit CTRL-ESC.

;More Fun With BOUNCE ;by Joel Gluck ;for ANALOG COMPUTING BYTE ARRAY xx(256),yy(256), xd(256),yd(256) BYTE xc,yc,hidden,cmode,TIME=20, RANDOM=53770,CONSOL=53279, CURSC=708,CH=764,NEWCOL=710, dist=[0],audball=[0] CARD num=[0],curspeed=[1500], ballspeed=[900] CARD ARRAY linept(48) PROC gr5init() CARD scrn=88 BYTE line,BALLCOL=709,WALLCOL=710 Graphics(5) FOR line=0 TO 47 DO linept(line)=scrn+20*line OD BALLCOL=$0C WALLCOL=$94 RETURN PROC plot5(BYTE x,y,col) BYTE POINTER pixel BYTE ARRAY colfil= [0 85 170 255], mask= [63 207 243 252], mask2= [192 48 12 3] pixel = linept(y)+(x RSH 2) pixel^ = pixel^ & mask(x & 3) % (colfil(col) & mask2(x & 3)) RETURN BYTE FUNC locate5(BYTE x,y) BYTE POINTER pixel BYTE ARRAY mask= [192 48 12 3] pixel = linept(y)+(x RSH 2) RETURN((pixel^ & mask(x & 3)) RSH (((x & 3) XOR 3) LSH 1)) PROC hline(BYTE y,c) BYTE i FOR i = 0 TO 79 DO plot5(i,y,c) OD RETURN PROC vline(BYTE x,c) BYTE i FOR i = 0 TO 47 DO plot5(x,i,c) OD RETURN PROC pauz(CARD p) CARD i FOR i=1 TO p DO OD RETURN PROC f16(BYTE x,y) BYTE g,a,b g=Locate(x,y) IF g=32 THEN RETURN FI g==+128 NEWCOL=15 b=y DO color=0 Plot(x,b) b==-1 color=g Plot(x,b) IF b=2 THEN EXIT FI Sound(0,b,8,8) pauz(700+x*50) OD a=x DO color=0 Plot(a,b) a==+1 color=g Plot(a,b) IF a=19 THEN EXIT FI Sound(0,a,8,8) pauz(700+x*50) OD color=0 Plot(a,b) SndRst() RETURN PROC colburst(BYTE x,y) BYTE g,c,a g=Locate(x,y) IF g=32 THEN RETURN FI g=g+128 NEWCOL=(Rand(16) LSH 4) % 10 color=g a=x-1 IF a>13 THEN a=0 FI Plot(x,a) DrawTo(x,y) FOR c=0 TO 15 DO Sound(0,0,4,15-c) pauz(400) OD color=0 Plot(x,0) DrawTo(x,y) SndRst() RETURN PROC dropkick(BYTE x,y) BYTE g,h,a,b g=Locate(x,y) IF g=32 THEN RETURN FI g==+128 NEWCOL=152 b=y DO color=0 Plot(x,b) b==+1 color=g Plot(x,b) IF b=23 THEN EXIT FI Sound(0,b+10+(x LSH 1),10,8) Sound(1,b+20+(x LSH 1),10,8) pauz(400) OD SndRst() h=0 NEWCOL=159 a=x DO color=h Plot(a,b) h=Locate(a+1,b-1) a==+1 b==-1 color=g Plot(a,b) IF a=18 OR b=1 THEN EXIT FI Sound(0,a-x,8,(b RSH 1)) pauz(800) OD color=0 Plot(a,b) SndRst() RETURN PROC foo() BYTE v FOR v=0 TO 15 DO Sound(0,255,10,15-v) Sound(1,0,8,8-(v RSH 1)) pauz(500) OD SndRst() RETURN PROC intro() BYTE x Graphics(17) CURSC=$08 Position(0,10) PrintD(6,"MORE FUN WITH") Position(0,12) PrintD(6,"B O U N C E !") Position(0,14) PrintD(6,"BY JOEL GLUCK") pauz(65000) pauz(65000) pauz(65000) FOR x=0 TO 12 DO f16(12-x,10) OD FOR x=0 TO 12 DO colburst(x,12) OD FOR x=0 TO 12 DO dropkick(12-x,14) OD CURSC=$48 Position(14,1) PrintD(6,"ANALOG") foo() Position(11,3) PrintD(6,"COMPUTING") foo() Position(12,5) PrintD(6,"FEBRUARY") foo() Position(16,7) PrintD(6,"1985") foo() pauz(65000) pauz(65000) pauz(65000) RETURN PROC drawdoc() BYTE CURS=752 CURS=1 PutE() Print("Use joystick and ") PrintE("SPACE to draw/erase.") Print("Hit B for balls, ") PrintE("0-9 for brush speed.") Print("ESC clrs balls; ") PrintE("ctrl-ESC clrs screen.") Print("Press START to Bounce!") RETURN PROC clearscrn() BYTE a,b,g FOR b=1 TO 19 DO FOR a=1 TO 78 DO g=locate5(a,b) IF (g=2 OR CH>28) AND g>1 THEN plot5(a,b,0) Sound(0,b,6,4) IF CH=28 THEN pauz(300) FI FI g=locate5(a,39-b) IF (g=2 OR CH>28) AND g>1 THEN plot5(a,39-b,0) Sound(0,b,6,4) IF CH=28 THEN pauz(300) FI FI OD Sound(0,0,0,0) OD IF CH>28 OR hidden=2 THEN hidden=0 FI RETURN PROC movecursor(BYTE bflag) BYTE g,STIK=632,TRIG=644,vol BYTE ARRAY v=[2 2 2 0 2 1 1 1 0 2 0 0 0 1 1 1 1 2 1 0 1 1] INT cxd,cyd IF STIK<15 OR bflag=1 THEN cxd=v((STIK-5) LSH 1)-1 cyd=v(((STIK-5) LSH 1) % 1)-1 IF bflag=1 THEN cxd=2 FI g=hidden IF TRIG THEN vol=4 ELSE vol=10 g=cmode*3 FI Sound(0,(xc+yc)*cmode, 8+(cmode LSH 1), vol-(cmode LSH 1)) plot5(xc,yc,g) xc==+cxd yc==+cyd IF xc<1 THEN xc=78 FI IF xc>78 THEN xc=1 FI IF yc<1 THEN yc=38 FI IF yc>38 THEN yc=1 FI hidden=locate5(xc,yc) plot5(xc,yc,1) FI RETURN PROC audlayball() BYTE i,j,k FOR j=0 TO 2 DO FOR i=j*50 TO j*50+20 DO Sound(0,i,10,15-j*6) pauz(100) OD OD Sound(0,0,0,0) RETURN BYTE FUNC number() BYTE n,v v=CH Open(2,"K:",4,1) n=GetD(2) Close(2) CH=v IF n>47 AND n<58 THEN RETURN(57-n) ELSE RETURN(99) FI PROC audcmode() BYTE n FOR n=1 TO 5 DO IF cmode THEN Sound(0,100-n*10,10,4) ELSE Sound(1,150-n*10,10,4) Sound(0,5-n,8,6) FI pauz(2000) SndRst() pauz(1000) OD RETURN PROC cursor() BYTE n IF CH<>255 THEN IF CH=33 THEN cmode==XOR 1 audcmode() ELSEIF CH=28 OR CH=156 THEN clearscrn() ELSEIF CH=21 THEN hidden=2 plot5(xc,yc,2) movecursor(1) audlayball() ELSE n=number() IF n<99 THEN curspeed=n*500 FI FI CH=255 FI movecursor(0) RETURN PROC bouncedoc() CARD n PutE() n=num IF n=1 THEN PrintE("1 ball is bouncing.") ELSE PrintC(n) PrintE(" balls are bouncing.") FI PrintE("Hit digits 0-9 for speed.") Print("S changes sound focus, ") PrintE("N nudges ball.") Print("Press SELECT to Draw again.") RETURN PROC process(BYTE a,b) BYTE g g=locate5(a,b) IF g=2 THEN IF num<200 THEN xx(num)=a yy(num)=b num==+1 ELSE plot5(a,b,0) FI ELSEIF g=0 THEN plot5(a,b,1) FI RETURN PROC ballinit() BYTE a,b CURSC=$44 num=0 FOR b=1 TO 19 DO FOR a=1 TO 78 DO process(a,b) process(a,39-b) OD OD FOR a=0 TO num DO xd(a)=Rand(2) LSH 1 yd(a)=Rand(2) LSH 1 OD RETURN PROC moveball(BYTE n) BYTE g,pa,pb g=locate5(xx(n)+xd(n)-1,yy(n)+yd(n)-1) IF g<2 THEN plot5(xx(n),yy(n),0) xx(n)=xx(n)+xd(n)-1 yy(n)=yy(n)+yd(n)-1 plot5(xx(n),yy(n),2) IF n=audball THEN dist==+1 FI RETURN ELSE pb=locate5(xx(n),yy(n)+yd(n)-1) pa=locate5(xx(n)+xd(n)-1,yy(n)) IF n=audball THEN IF dist THEN Sound(0,170-((38-dist) LSH 2), 10,8) Sound(1,((38-dist) LSH 2), 10,8) FI dist=0 TIME=0 FI IF pa>1 THEN xd(n)=2-xd(n) IF pb>1 THEN yd(n)=2-yd(n) RETURN ELSE plot5(xx(n),yy(n),0) yy(n)=yy(n)+yd(n)-1 plot5(xx(n),yy(n),2) RETURN FI ELSEIF pb>1 THEN yd(n)=2-yd(n) plot5(xx(n),yy(n),0) xx(n)=xx(n)+xd(n)-1 plot5(xx(n),yy(n),2) RETURN ELSEIF Rand(2) THEN xd(n)=2-xd(n) ELSE yd(n)=2-yd(n) RETURN FI FI RETURN PROC cleanup() BYTE a,b FOR b=1 TO 19 DO FOR a=1 TO 78 DO IF locate5(a,b)=1 THEN plot5(a,b,0) FI IF locate5(a,39-b)=1 THEN plot5(a,39-b,0) FI OD OD RETURN PROC bounce() CARD i BYTE n ballinit() bouncedoc() audball=0 dist=0 IF num THEN DO FOR i=0 TO num-1 DO moveball(i) IF CH<>255 THEN IF CH=62 THEN audball==+1 IF audball=num THEN audball=0 FI dist=0 ELSEIF CH=35 THEN xd(audball)=2-xd(audball) ELSE n=number() IF n<99 THEN ballspeed=n*n*100 FI FI CH=255 FI IF CONSOL=5 THEN EXIT FI OD pauz(ballspeed) IF TIME THEN SndRst() FI UNTIL CONSOL=5 OD SndRst() FI cleanup() RETURN PROC MFWB() intro() gr5init() hline(0,3) hline(39,3) vline(0,3) vline(79,3) DO drawdoc() xc=39 yc=19 hidden=locate5(xc,yc) cmode=1 plot5(xc,yc,1) DO cursor() CURSC=TIME pauz(curspeed) Sound(0,0,0,0) pauz(curspeed) UNTIL CONSOL=6 OD plot5(xc,yc,hidden) CH=255 bounce() OD RETURN