Galton box animation: Difference between revisions
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{{task|Galton box animation}} |
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{{task}}[[Category:Animation]] [[Category:Randomness]] {{omit from|GUISS}} |
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[[Category:Animation]] |
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[[Category:Randomness]] |
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{{omit from|GUISS}} |
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Generate an animated simulation of [[wp:Bean_machine|Sir Francis Galton's device]]. |
Generate an animated simulation of [[wp:Bean_machine|Sir Francis Galton's device]]. |
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An example can be found to the right. [[File:Galtonbox-Unicon.PNG|thumb|Example of a Galton Box at the end of animation.]] |
An example can be found to the right. [[File:Galtonbox-Unicon.PNG|thumb|Example of a Galton Box at the end of animation.]] |
Revision as of 05:20, 20 February 2015
You are encouraged to solve this task according to the task description, using any language you may know.
Generate an animated simulation of Sir Francis Galton's device.
An example can be found to the right.
In a Galton box, there are a set of pins arranged in a triangular pattern. A number of balls are dropped so that they fall in line with the top pin, deflecting to the left or the right of the pin. The ball continues to fall to the left or right of subsequent pins before arriving at one of the collection points between and to the sides of the bottom row of pins.
For the purpose of this task the box should have at least 5 pins on the bottom row. Your solution can use graphics or ASCII animation. Provide a sample of the output/display such as a screenshot.
Your solution can have either one or more balls in flight at the same time. If multiple balls are in flight, ensure they don't interfere with each other.
Your solution should allow users to specify the number of balls or it should run until full or a preset limit. Optionally, display the number of balls.
AutoHotkey
Uses an edit box for the (text based) animation <lang AutoHotkey>AutoTrim Off
- User settings
bottompegs := 6 SleepTime := 200 fallspace := 30
- create the board
out := (pad2 := Space(bottompegs*2+1)) "`n" Loop % bottompegs { out .= Space(bottompegs-A_Index+1) Loop % A_Index out .= "* " out .= Space(bottompegs-A_Index+1) . "`n" } StringTrimRight, strboard, out, 1 ; remove last newline Loop % fallspace-1 strboard .= "`n" . pad2 strboard .= "`n" Loop % bottompegs*2+1 strboard .= "="
- Create Gui
Gui Font, , Consolas Gui -Caption Gui Margin, 0, 0 Gui, Add, edit, -VScroll vE, % strboard Gui Show Loop { ballX := bottompegs+1, BallY := 1 strboard := ChangeChar(strboard, BallX, ballY, "O") GuiControl,, E, % strboard sleep SleepTime ; Make ball fall and bounce Loop % bottompegs { strboard := ChangeChar(strboard, BallX, BallY, " ") ballY += 1 ballX += RandAdd() ; MsgBox % ballX ", " ballY GuiControl,, E, % strboard := ChangeChar(strboard, ballX, ballY, "O") sleep SleepTime } ; now fall to the bottom While GetChar(strboard, BallX, BallY+1) = A_Space { strboard := ChangeChar(strboard, BallX, BallY, " ") BallY += 1 strboard := ChangeChar(strboard, BallX, BallY, "O") GuiControl,, E, % strboard sleep SleepTime } } ~Esc:: GuiClose: ExitApp
Space(n){ If n return " " Space(n-1) return "" } RandAdd(){ Random, n, 3, 4 return (n=3 ? -1 : 1) }
GetChar(s, x, y){ Loop Parse, s, `n if (A_Index = y) return SubStr(A_LoopField, x, 1) } ChangeChar(s, x, y, c){ Loop Parse, s, `n { If (A_Index = y) { Loop Parse, A_LoopField If (A_Index = x) out .= c else out .= A_LoopField } else out .= A_LoopField out .= "`n" } StringTrimRight, out, out, 1 ; removes the last newline return out }</lang>While the number of pegs, and falling space are configurable, here's output shortly after starting one configuration:
* * *O * * * * * * * * * * * * * * * * * * O O O O O O O O O O O O =============
BASIC256
<lang basic256>graphsize 150,125 fastgraphics color black rect 0,0,graphwidth,graphheight refresh
N = 10 # number of balls M = 5 # number of pins in last row dim ball(N,5) # (pos_x to center, level, x, y, direction} dim cnt(M+1)
rad = 6 slow = 0.3 diamond = {0,rad,rad,0,0,-rad,-rad,0} stepx = {rad/sqr(2),rad/2,rad/2,(1-1/sqr(2))*rad,0} stepy = {(1-1/sqr(2))*rad,rad/2,rad/2,rad/sqr(2),rad} CX = graphwidth/2 : CY = graphheight/2 iters = 0
- Draw pins
for i = 1 to M y = 3*rad*i for j = 1 to i dx = (j-i\2-1)*4*rad + ((i-1)%2)*2*rad color purple stamp CX+dx,y,1.0,diamond color darkpurple stamp CX+dx,y,0.6,diamond next j next i gosub saverefresh
R = 0 : C = 0 font "Tahoma",10,50 do # Release ball if R<N then R = R + 1 ball[R-1,2] = CX : ball[R-1,3] = rad*(1-stepx[?]) : ball[R-1,4] = 0 # How many balls are released color black text 5,5,(R-1)+" balls" color green text 5,5,(R)+" balls" end if # Animate balls on this step for it = 0 to stepx[?]-1 for b = 0 to R-1 gosub moveball next b gosub saverefresh pause slow/stepx[?] next it # Where to go on the next step? for b = 0 to R-1 ball[b,1] = ball[b,1] + 1 if ball[b,1]<=M then if rand>=0.5 then ball[b,4] = 1 else ball[b,4] = -1 end if ball[b,0] = ball[b,0] + ball[b,4] else if ball[b,4]<>0 then gosub eraseball i = (ball[b,0]+M)/2 cnt[i] = cnt[i] + 1 ball[b,4] = 0 C = C + 1 end if end if next b # Draw counter color green y = 3*rad*(M+1) for j = 0 to M dx = (j-(M+1)\2)*4*rad + (M%2)*2*rad stamp CX+dx,y,{-1.2*rad,0,1.2*rad,0,1.2*rad,2*cnt[j],-1.2*rad,2*cnt[j]} next j gosub saverefresh until C >= N end
moveball: if ball[b,1]>M then return gosub eraseball if ball[b,4]<>0.0 then ball[b,2] = ball[b,2]+ball[b,4]*stepx[it] ball[b,3] = ball[b,3]+stepy[it] else ball[b,3] = ball[b,3]+rad end if gosub drawball
drawball: color darkgreen circle ball[b,2],ball[b,3],rad-1 color green circle ball[b,2],ball[b,3],rad-2 return
eraseball: color black circle ball[b,2],ball[b,3],rad-1 return
saverefresh: num$ = string(iters) for k = 1 to 4-length(num$) num$ = "0"+num$ next k imgsave num$+"-Galton_box_BASIC-256.png", "PNG" iters = iters + 1 refresh return</lang>
BBC BASIC
<lang bbcbasic> maxBalls% = 10
DIM ballX%(maxBalls%), ballY%(maxBalls%) VDU 23,22,180;400;8,16,16,128 ORIGIN 180,0 OFF REM Draw the pins: GCOL 9 FOR row% = 1 TO 7 FOR col% = 1 TO row% CIRCLE FILL 40*col% - 20*row% - 20, 800 - 40*row%, 12 NEXT NEXT row% REM Animate last% = 0 tick% = 0 GCOL 3,3 REPEAT IF RND(10) = 5 IF (tick% - last%) > 10 THEN FOR ball% = 1 TO maxBalls% IF ballY%(ball%) = 0 THEN ballX%(ball%) = 0 ballY%(ball%) = 800 last% = tick% EXIT FOR ENDIF NEXT ENDIF FOR ball% = 1 TO maxBalls% IF ballY%(ball%) CIRCLE FILL ballX%(ball%), ballY%(ball%), 12 IF POINT(ballX%(ball%),ballY%(ball%)-10) = 12 OR ballY%(ball%) < 12 THEN IF ballY%(ball%) > 500 END ballY%(ball%) = 0 ENDIF NEXT WAIT 2 FOR ball% = 1 TO maxBalls% IF ballY%(ball%) THEN CIRCLE FILL ballX%(ball%), ballY%(ball%), 12 ballY%(ball%) -= 4 IF POINT(ballX%(ball%),ballY%(ball%)-10) = 9 THEN ballX%(ball%) += 40 * (RND(2) - 1.5) ENDIF ENDIF NEXT tick% += 1 UNTIL FALSE</lang>
C
<lang c>#include <stdio.h>
- include <stdlib.h>
- include <string.h>
- define BALLS 1024
int n, w, h = 45, *x, *y, cnt = 0; char *b;
- define B(y, x) b[(y)*w + x]
- define C(y, x) ' ' == b[(y)*w + x]
- define V(i) B(y[i], x[i])
inline int rnd(int a) { return (rand()/(RAND_MAX/a))%a; }
void show_board() { int i, j; for (puts("\033[H"), i = 0; i < h; i++, putchar('\n')) for (j = 0; j < w; j++, putchar(' ')) printf(B(i, j) == '*' ? C(i - 1, j) ? "\033[32m%c\033[m" : "\033[31m%c\033[m" : "%c", B(i, j)); }
void init() { int i, j; puts("\033[H\033[J"); b = malloc(w * h); memset(b, ' ', w * h);
x = malloc(sizeof(int) * BALLS * 2); y = x + BALLS;
for (i = 0; i < n; i++) for (j = -i; j <= i; j += 2) B(2 * i+2, j + w/2) = '*'; srand(time(0)); }
void move(int idx) { int xx = x[idx], yy = y[idx], c, kill = 0, sl = 3, o = 0;
if (yy < 0) return; if (yy == h - 1) { y[idx] = -1; return; }
switch(c = B(yy + 1, xx)) { case ' ': yy++; break; case '*': sl = 1; default: if (xx < w - 1 && C(yy, xx + 1) && C(yy + 1, xx + 1)) if (!rnd(sl++)) o = 1; if (xx && C(yy, xx - 1) && C(yy + 1, xx - 1)) if (!rnd(sl++)) o = -1; if (!o) kill = 1; xx += o; }
c = V(idx); V(idx) = ' '; idx[y] = yy, idx[x] = xx; B(yy, xx) = c; if (kill) idx[y] = -1; }
int run(void) { static int step = 0; int i; for (i = 0; i < cnt; i++) move(i); if (2 == ++step && cnt < BALLS) { step = 0; x[cnt] = w/2; y[cnt] = 0; if (V(cnt) != ' ') return 0; V(cnt) = rnd(80) + 43; cnt++; } return 1; }
int main(int c, char **v) { if (c < 2 || (n = atoi(v[1])) <= 3) n = 5; if (n >= 20) n = 20; w = n * 2 + 1; init();
do { show_board(), usleep(60000); } while (run());
return 0; }</lang>
Sample out put at begining of a run:
* * * * * * * * * * * * * * *
D
To keep the code simpler some corner cases are ignored. <lang d>import std.stdio, std.algorithm, std.random, std.array;
enum int boxW = 41, boxH = 37; // Galton box width and height. enum int pinsBaseW = 19; // Pins triangle base size. enum int nMaxBalls = 55; // Number of balls.
static assert(boxW >= 2 && boxH >= 2); static assert((boxW - 4) >= (pinsBaseW * 2 - 1)); static assert((boxH - 3) >= pinsBaseW); enum centerH = pinsBaseW + (boxW - (pinsBaseW * 2 - 1)) / 2 - 1;
enum Cell : char { empty = ' ',
ball = 'o', wall = '|', corner = '+', floor = '-', pin = '.' }
Cell[boxW][boxH] box; // Galton box. Will be printed upside-down.
struct Ball {
int x, y; // Position.
this(in int x_, in int y_) nothrow @safe @nogc in { assert(box[y_][x_] == Cell.empty); } body { this.x = x_; this.y = y_; box[y][x] = Cell.ball; }
nothrow const @safe @nogc invariant { assert(x >= 0 && x < boxW && y >= 0 && y < boxH); assert(box[y][x] == Cell.ball); }
void doStep() { if (y <= 0) return; // Reached the bottom of the box.
final switch (box[y - 1][x]) with (Cell) { case empty: box[y][x] = Cell.empty; y--; box[y][x] = Cell.ball; break; case ball, wall, corner, floor: // It's frozen. (It always piles on other balls). break; case pin: box[y][x] = Cell.empty; y--; if (box[y][x - 1] == Cell.empty && box[y][x + 1] == Cell.empty) { x += uniform(0, 2) * 2 - 1; box[y][x] = Cell.ball; return; } else if (box[y][x - 1] == Cell.empty) { x++; } else { x--; } box[y][x] = Cell.ball; break; } }
}
void initializeBox() {
// Set ceiling and floor: box[0][] = Cell.corner ~ [Cell.floor].replicate(boxW - 2) ~ Cell.corner; box[$ - 1][] = box[0][];
// Set walls: foreach (immutable r; 1 .. boxH - 1) box[r][0] = box[r][$ - 1] = Cell.wall;
// Set pins: foreach (immutable nPins; 1 .. pinsBaseW + 1) foreach (pin; 0 .. nPins) box[boxH - 2 - nPins][centerH + 1 - nPins + pin * 2] = Cell.pin;
}
void drawBox() {
foreach_reverse (const ref row; box) writefln("%(%c%)", row);
}
void main() {
initializeBox; Ball[] balls;
foreach (const i; 0 .. nMaxBalls + boxH) { writefln("\nStep %d:", i); if (i < nMaxBalls) balls ~= Ball(centerH, boxH - 2); // Add ball. drawBox;
// Next step for the simulation. // Frozen balls are kept in balls array for simplicity. foreach (ref b; balls) b.doStep; }
}</lang>
- Output:
Step 0: +---------------------------------------+ | o | | . | | . . | | . . . | | . . . . | | . . . . . | | . . . . . . | | . . . . . . . | | . . . . . . . . | | . . . . . . . . . | | . . . . . . . . . . | | . . . . . . . . . . . | | . . . . . . . . . . . . | | . . . . . . . . . . . . . | | . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . . . . | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +---------------------------------------+ ... Step 39: +---------------------------------------+ | o | | o. | | . .o | | . .o. | | .o. . . | | .o. . . . | | . . .o. . . | | . . .o. . . . | | . . .o. . . . . | | . . . .o. . . . . | | . . . . . .o. . . . | | . . . . . .o. . . . . | | . . . .o. . . . . . . . | | . . . . . .o. . . . . . . | | . . . . . . .o. . . . . . . | | . . . . . .o. . . . . . . . . | | . . . .o. . . . . . . . . . . . | | . . . . . . . . .o. . . . . . . . | | . . . . . .o. . . . . . . . . . . . | | . . . . . . . .o. . . . . . . . . . . | | o | | o | | o | | o | | o | | o | | o | | o | | o | | o | | o | | o o | | o | | o o o | | o o o | +---------------------------------------+ ... Step 91: +---------------------------------------+ | | | . | | . . | | . . . | | . . . . | | . . . . . | | . . . . . . | | . . . . . . . | | . . . . . . . . | | . . . . . . . . . | | . . . . . . . . . . | | . . . . . . . . . . . | | . . . . . . . . . . . . | | . . . . . . . . . . . . . | | . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . . . | | . . . . . . . . . . . . . . . . . . . | | | | | | o | | o o | | o o | | o o | | o o | | o o | | o o o | | o o o o | | o o o o | | o o o o o | | o o o o o o o | | o o o o o o o o o o | | o o o o o o o o o o o | +---------------------------------------+
Icon and Unicon
The code here is adapted from the Unicon Book.
<lang Icon>link graphics
global pegsize, pegsize2, height, width, delay
procedure main(args) # galton box simulation from Unicon book
pegsize2 := (pegsize := 10) * 2 # pegs & steps delay := 2 # ms delay setup_galtonwindow(pegsize) n := integer(args[1]) | 100 # balls to drop every 1 to n do galton(pegsize) WDone()
end
procedure setup_galtonwindow(n) # Draw n levels of pegs, local xpos, ypos, i, j
# Pegboard size is 2n-1 square # Expected max value of histogram is (n, n/2)/2^n # ... approximate with something simpler?
height := n*n/2*pegsize + (width := (2*n+1)*pegsize) Window("size=" || width || "," || height, "fg=grayish-white") WAttrib("fg=dark-grey") every ypos := (i := 1 to n) * pegsize2 do { xpos := width/2 - (i - 1) * pegsize - pegsize/2 - pegsize2 every 1 to i do FillArc(xpos +:= pegsize2, ypos, pegsize, pegsize) } WAttrib("fg=black","drawop=reverse") # set drawing mode for balls
end
procedure galton(n) # drop a ball into the galton box local xpos, ypos, oldx, oldy
xpos := oldx := width/2 - pegsize/2 ypos := oldy := pegsize every 1 to n do { # For every ball... xpos +:= ((?2 = 1) | -1) * pegsize # +/- pegsize animate(.oldx, .oldy, oldx := xpos, oldy := ypos +:= pegsize2) } animate(xpos, ypos, xpos, ypos + 40) # Now the ball falls ... animate(xpos, ypos+40, xpos, ypos + 200) # ... to the floor draw_ball(xpos) # Record this ball
end
procedure animate(xfrom, yfrom, xto, yto)
animate_actual(xfrom, yfrom, xto, yfrom, 4) animate_actual(xto, yfrom, xto, yto, 10)
end
procedure animate_actual(xfrom, yfrom, xto, yto, steps) # attribs already set
local x, y, xstep, ystep, lastx, lasty
x -:= xstep := (xto - (x := xfrom))/steps y -:= ystep := (yto - (y := yfrom))/steps every 1 to steps do { FillArc(lastx := x +:= xstep, lasty := y +:= ystep, pegsize, pegsize) WDelay(delay) # wait in ms FillArc(x, y, pegsize, pegsize) }
end
procedure draw_ball(x) static ballcounts initial ballcounts := table(0)
FillArc(x, height-(ballcounts[x] +:= 1)*pegsize, pegsize, pegsize)
end</lang>
J
First, we need to a representation for our pins:
<lang j>initpins=: '* ' {~ '1'&i.@(-@|. |."_1 [: ":@-.&0"1 <:~/~)@i.</lang>
For example:
<lang j> initpins 4
* * * * * *
- * * *</lang>
Note that we could introduce other pin arrangements, for example a Sierpinski triangle:
<lang j>initSpins=: [: }.@|. (1- 2&^@>:) ]\ [: ,] (,~ ,.~)@]^:[ ,: bind '* '</lang>
... but this will not be too interesting to use, because of the lack of interior pins for the balls to bounce off of.
Anyways, once we have that, we can add balls to our picture:
<lang j>init=: ' ',. ' ',.~ ] ,~ ' ',~ ' o' {~ (# ' ' ~: 1&{.)</lang>
For example:
<lang j> 3 (init initpins) 4
o o o * * * * * * * * * * </lang>
Now we just need some way of updating our datastructure.
We will need a mechanism to shift a ball left or right if it's above a pin:
<lang>bounce=: (C.~ ] <"1@:+ 0 1 -~/~ ? @: (2"0))"1 [: I. 'o*'&E."1&.|:</lang>
And, a mechanism to make the balls fall:
<lang>shift=: 4 :0
fill=. {.0#,y x |.!.fill y
)</lang>
And then we need to separate out the balls from the pins, so the balls fall and the pins do not. Note also that in this representation, balls will have to fall when they bounce because they cannot occupy the same space that a pin occupies.
We will also want some way of preventing the balls from falling forever. For this task it's probably sufficient to introduce a baseline sufficiently deep to hold the stacks and have balls instantly fall as close as they can to the baseline once they are past the pins.
<lang j>pins=: '*'&= balls=: 'o'&=
bounce=: (C.~ 0 1 <@(-/~) [: (+ ?@2:"0) I.)"1
nxt=: ' ',~ [: clean ' *o' {~ pins + 2 * _1 shift balls bounce balls *. 1 shift pins
clean2=: ({. , -.&' '"1&.|:&.|.@}.)~ 1 + >./@(# | '*' i:~"1 |:) clean1=: #~ 1 1 -.@E. *./"1@:=&' ' clean=: clean1@clean2</lang>
For example:
<lang j> nxt nxt 3 (init initpins) 4
o o o* * * * * * * * * * </lang>
Or, showing an entire animation sequence:
<lang j> nxt&.>^:a: <7 (init ' ',.' ',.~ initpins) 5 ┌─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┐ │ o │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ o │ o │ o │ o │ o │ o │ o │ o │ *o │ * │ * │ * │ * │ * │ │ o │ o │ o │ o │ o │ o │ o │ *o │ *o* │ *o* │ * * │ * * │ * * │ * * │ │ o │ o │ o │ o │ o │ o │ *o │ * *o │ * * *o │ * *o* │ * *o* │ * * * │ * * * │ * * * │ │ o │ o │ o │ o │ o │ *o │ * *o │ * *o* │ * *o* * │ * * * *o │ * *o* * │ * *o* * │ * * * * │ * * * * │ │ o │ o │ o │ o │ o* │ o* * │ *o* * │ * *o* * │ * * *o* * │ * *o* * * │ * * * * *o │ * * *o* * │ * *o* * * │ * * * * * │ │ o │ o │ o │ *o │ *o* │ * *o* │ * * *o* │ * * *o* * │ o │ o │ o │ o │ o │ o │ │ │ o │ *o │ * *o │ * *o* │ * *o* * │ * * *o* * │ o │ o │ o │ o │ o │ o │ o │ │ * │ * │ * * │ * * * │ * * * * │ * * * * * │ │ │ │ o │ o o │ o o o │ o │ o o │ │ * * │ * * │ * * * │ * * * * │ * * * * * │ │ │ │ │ │ │ │ o o o │ o o o │ │ * * * │ * * * │ * * * * │ * * * * * │ │ │ │ │ │ │ │ │ │ │ │ * * * * │ * * * * │ * * * * * │ │ │ │ │ │ │ │ │ │ │ │ │ * * * * * │ * * * * * │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ └─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┘</lang>
Java
The balls keep track of where they are, and we just have to move them down and print. You might easily adjust this to take command line input for the numbers of pins and balls. I'm sure that this could be a lot shorter... <lang Java>import java.util.Random; import java.util.List; import java.util.ArrayList;
public class GaltonBox {
public static void main( final String[] args ) { new GaltonBox( 8, 200 ).run(); }
private final int m_pinRows; private final int m_startRow; private final Position[] m_balls; private final Random m_random = new Random();
public GaltonBox( final int pinRows, final int ballCount ) { m_pinRows = pinRows; m_startRow = pinRows + 1; m_balls = new Position[ ballCount ];
for ( int ball = 0; ball < ballCount; ball++ ) m_balls[ ball ] = new Position( m_startRow, 0, 'o' ); }
private static class Position { int m_row; int m_col; char m_char;
Position( final int row, final int col, final char ch ) { m_row = row; m_col = col; m_char = ch; } }
public void run() { for ( int ballsInPlay = m_balls.length; ballsInPlay > 0; ) { ballsInPlay = dropBalls(); print(); } }
private int dropBalls() { int ballsInPlay = 0; int ballToStart = -1;
// Pick a ball to start dropping for ( int ball = 0; ball < m_balls.length; ball++ ) if ( m_balls[ ball ].m_row == m_startRow ) ballToStart = ball;
// Drop balls that are already in play for ( int ball = 0; ball < m_balls.length; ball++ ) if ( ball == ballToStart ) { m_balls[ ball ].m_row = m_pinRows; ballsInPlay++; } else if ( m_balls[ ball ].m_row > 0 && m_balls[ ball ].m_row != m_startRow ) { m_balls[ ball ].m_row -= 1; m_balls[ ball ].m_col += m_random.nextInt( 2 ); if ( 0 != m_balls[ ball ].m_row ) ballsInPlay++; }
return ballsInPlay; }
private void print() { for ( int row = m_startRow; row --> 1; ) { for ( int ball = 0; ball < m_balls.length; ball++ ) if ( m_balls[ ball ].m_row == row ) printBall( m_balls[ ball ] ); System.out.println(); printPins( row ); } printCollectors(); System.out.println(); }
private static void printBall( final Position pos ) { for ( int col = pos.m_row + 1; col --> 0; ) System.out.print( ' ' ); for ( int col = 0; col < pos.m_col; col++ ) System.out.print( " " ); System.out.print( pos.m_char ); }
private void printPins( final int row ) { for ( int col = row + 1; col --> 0; ) System.out.print( ' ' ); for ( int col = m_startRow - row; col --> 0; ) System.out.print( ". " ); System.out.println(); }
private void printCollectors() { final List<List<Position>> collectors = new ArrayList<List<Position>>();
for ( int col = 0; col < m_startRow; col++ ) { final List<Position> collector = new ArrayList<Position>();
collectors.add( collector ); for ( int ball = 0; ball < m_balls.length; ball++ ) if ( m_balls[ ball ].m_row == 0 && m_balls[ ball ].m_col == col ) collector.add( m_balls[ ball ] ); }
for ( int row = 0, rows = longest( collectors ); row < rows; row++ ) { for ( int col = 0; col < m_startRow; col++ ) { final List<Position> collector = collectors.get( col ); final int pos = row + collector.size() - rows;
System.out.print( '|' ); if ( pos >= 0 ) System.out.print( collector.get( pos ).m_char ); else System.out.print( ' ' ); } System.out.println( '|' ); } }
private static final int longest( final List<List<Position>> collectors ) { int result = 0;
for ( final List<Position> collector : collectors ) result = Math.max( collector.size(), result );
return result; }
}</lang>
- Output:
When only five balls have begun to fall through the pins:
o . o . . o . . . o . . . . o . . . . . . . . . . . . . . . . . . . . . . . . . .
Later, some balls have arrived in the collectors:
o . o . . o . . . o . . . . o . . . . . o . . . . . . o . . . . . . . o . . . . . . . . | | | | | |o| | | | | | | |o|o|o| | | |
Note that the collectors are as deep as required.
Finally, all the balls are in the collectors:
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . | | | | |o| | | | | | | | | |o| | | | | | | | | |o| | | | | | | | | |o| | | | | | | | | |o| | | | | | | | | |o| | | | | | | | | |o| | | | | | | | | |o| | | | | | | | |o|o| | | | | | | | |o|o| | | | | | | | |o|o| | | | | | | | |o|o| | | | | | | | |o|o| | | | | | | | |o|o| | | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o| | | | | | | |o|o|o|o| | | | | | |o|o|o|o| | | | | | |o|o|o|o| | | | | | |o|o|o|o| | | | | | |o|o|o|o| | | | | | |o|o|o|o| | | | | | |o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o| | | | | |o|o|o|o|o|o| | | | |o|o|o|o|o|o| | | | |o|o|o|o|o|o| | | |o|o|o|o|o|o|o| | | |o|o|o|o|o|o|o| | | |o|o|o|o|o|o|o| |
Perl 6
<lang Perl6>my $row-count = 6;
constant $peg = "*"; constant @coin-icons = "\c[UPPER HALF BLOCK]", "\c[LOWER HALF BLOCK]";
sub display-board(@positions, @stats is copy, $halfstep) {
my $coin = @coin-icons[$halfstep.Int];
state @board-tmpl = { # precompute a board my @tmpl; sub out(*@stuff) { @tmpl.push: @stuff>>.ords.item; } # three lines of space above for (1..3) { out " ", " " x (2 * $row-count); } # $row-count lines of pegs for ($row-count...1) Z (1...$row-count) -> $spaces, $pegs { out " ", " " x $spaces, ($peg xx $pegs).join(" "), " " x $spaces; } # four lines of space below for (1..4) { out " ", " " x (2 * $row-count); } @tmpl }();
my $midpos = $row-count + 2;
my @output; { # collect all the output and output it all at once at the end sub say(Str $foo) { @output.push: $foo, "\n"; } sub print(Str $foo) { @output.push: $foo; }
# make some space above the picture say "" for ^10;
my @output-lines = map { [map *.clone, @$_].item }, @board-tmpl; # place the coins for @positions.kv -> $line, $pos { next unless $pos.defined; @output-lines[$line][$pos + $midpos] = $coin.ord; } # output the board with its coins for @output-lines -> @line { say @line>>.chr.join(""); }
# show the statistics my $padding = 0; while any(@stats) > 0 { $padding++; print " "; @stats = do for @stats -> $stat { given $stat { when 1 { print "\c[UPPER HALF BLOCK]"; $stat - 1; } when * <= 0 { print " "; 0 } default { print "\c[FULL BLOCK]"; $stat - 2; } } } say ""; } say "" for $padding...^10; } say @output.join("");
}
sub simulate($coins is copy) {
my $alive = True;
sub hits-peg($x, $y) { if 3 <= $y < 3 + $row-count and -($y - 2) <= $x <= $y - 2 { return not ($x - $y) %% 2; } return False; }
my @coins = Int xx (3 + $row-count + 4); my @stats = 0 xx ($row-count * 2); # this line will dispense coins until turned off. @coins[0] = 0; while $alive { $alive = False; # if a coin falls through the bottom, count it given @coins[*-1] { when *.defined { @stats[$_ + $row-count]++; } }
# move every coin down one row for ( 3 + $row-count + 3 )...1 -> $line { my $coinpos = @coins[$line - 1];
@coins[$line] = do if not $coinpos.defined { Nil } elsif hits-peg($coinpos, $line) { # when a coin from above hits a peg, it will bounce to either side. $alive = True; ($coinpos - 1, $coinpos + 1).pick; } else { # if there was a coin above, it will fall to this position. $alive = True; $coinpos; } } # let the coin dispenser blink and turn it off if we run out of coins if @coins[0].defined { @coins[0] = Nil } elsif --$coins > 0 { @coins[0] = 0 }
# smooth out the two halfsteps of the animation my $start-time; ENTER { $start-time = now } my $wait-time = now - $start-time;
sleep 0.1 - $wait-time if $wait-time < 0.1; for @coin-icons.keys { sleep $wait-time max 0.1; display-board(@coins, @stats, $_); } }
}
sub MAIN($coins = 20, $peg-lines = 6) {
$row-count = $peg-lines; simulate($coins);
}</lang>
PicoLisp
<lang PicoLisp>(de galtonBox (Pins Height)
(let (Bins (need (inc (* 2 Pins)) 0) X 0 Y 0) (until (= Height (apply max Bins)) (call 'clear) (cond ((=0 Y) (setq X (inc Pins) Y 1)) ((> (inc 'Y) Pins) (inc (nth Bins X)) (zero Y) ) ) ((if (rand T) inc dec) 'X) (for Row Pins (for Col (+ Pins Row 1) (let D (dec (- Col (- Pins Row))) (prin (cond ((and (= X Col) (= Y Row)) "o") ((and (gt0 D) (bit? 1 D)) ".") (T " ") ) ) ) ) (prinl) ) (prinl) (for H (range Height 1) (for B Bins (prin (if (>= B H) "o" " ")) ) (prinl) ) (wait 200) ) ) )</lang>
Test: <lang PicoLisp>(galtonBox 9 11)</lang>
- Output:
# Snapshot after a few seconds: . . . . . . . . . . . . . . . .o. . . . . . . . . . . . . . . . . . . . . . . . . . . . . o o o o o o o
# Final state: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . o o o o o o o o o o o o o o o o o o o o o o o o o
Prolog
Works with SWI-Prolog and XPCE.
<lang Prolog>:- dynamic tubes/1.
- - dynamic balls/2.
- - dynamic stop/1.
% number of rows of pins (0 -> 9) row(9).
galton_box :- retractall(tubes(_)), retractall(balls(_,_)), retractall(stop(_)), assert(stop(@off)), new(D, window('Galton Box')), send(D, size, size(520,700)), display_pins(D), new(ChTubes, chain), assert(tubes(ChTubes)), display_tubes(D, ChTubes), new(Balls, chain), new(B, ball(D)), send(Balls, append, B), assert(balls(Balls, D)), send(D, done_message, and(message(ChTubes, clear), message(ChTubes, free), message(Balls, for_all, message(@arg1, free)), message(Balls, clear), message(Balls, free), message(@receiver, destroy))), send(D, open).
% class pin, balls travel between pins
- - pce_begin_class(pin, circle, "pin").
initialise(P, Pos) :-> send(P, send_super, initialise, 18), send(P, fill_pattern, new(_, colour(@default, 0, 0, 0))), get(Pos, x, X), get(Pos, y, Y), send(P, geometry, x := X, y := Y).
- - pce_end_class.
% class tube, balls fall in them
- - pce_begin_class(tube, path, "tube where balls fall").
variable(indice, any, both, "index of the tube in the list"). variable(balls, any, both, "number of balls inside").
initialise(P, Ind, D) :-> row(Row), send(P, send_super, initialise, kind := poly), send(P, slot, balls, 0), send(P, slot, indice, Ind), X0 is 228 - Row * 20 + Ind * 40, X1 is X0 + 20, Y1 is 600, Y0 is 350, send_list(P, append, [point(X0, Y0), point(X0, Y1), point(X1,Y1), point(X1,Y0)]), send(D, display, P).
% animation stop when a tube is full add_ball(P) :-> get(P, slot, balls, B), B1 is B+1, send(P, slot, balls, B1), ( B1 = 12 -> retract(stop(_)), assert(stop(@on)) ; true).
- - pce_end_class.
% class ball
- - pce_begin_class(ball, circle, "ball").
variable(angle, any, both, "angle of the ball with the pin"). variable(dir, any, both, "left / right"). variable(pin, point, both, "pin under the ball when it falls"). variable(position, point, both, "position of the ball"). variable(max_descent, any, both, "max descent"). variable(state, any, both, "in_pins / in_tube"). variable(window, any, both, "window to display"). variable(mytimer, timer, both, "timer of the animation").
initialise(P, W) :-> send(P, send_super, initialise, 18), send(P, pen, 0), send(P, state, in_pins), send(P, fill_pattern, new(_, colour(@default, 65535, 0, 0))), Ang is 3 * pi / 2, send(P, slot, angle, Ang), send(P, slot, window, W), send(P, geometry, x := 250, y := 30), send(P, pin, point(250, 50)), send(P, choose_dir), send(P, mytimer, new(_, timer(0.005, message(P, move_ball)))), send(W, display, P), send(P?mytimer, start).
% method called when the object is destroyed % first the timer is stopped % then all the resources are freed unlink(P) :-> send(P?mytimer, stop), send(P, send_super, unlink).
choose_dir(P) :-> I is random(2), ( I = 1 -> Dir = left; Dir = right), send(P, dir, Dir).
move_ball(P) :-> get(P, state, State), ( State = in_pins -> send(P, move_ball_in_pins) ; send(P, move_ball_in_tube)).
move_ball_in_pins(P) :-> get(P, slot, angle, Ang), get(P, slot, pin, Pin), get(P, slot, dir, Dir), ( Dir = left -> Ang1 is Ang-0.15 ; Ang1 is Ang + 0.15), get(Pin, x, PX), get(Pin, y, PY), X is 21 * cos(Ang1) + PX, Y is 21 * sin(Ang1) + PY, send(P, geometry, x := X, y := Y), send(P?window, display, P), ( abs(Ang1 - pi) < 0.1 -> PX1 is PX - 20, send(P, next_move, PX1, PY) ; abs(Ang1 - 2 * pi) < 0.1 -> PX1 is PX + 20, send(P, next_move, PX1, PY) ; send(P, slot, angle, Ang1)).
next_move(P, PX, PY) :-> row(Row),
Ang2 is 3 * pi / 2, PY1 is PY + 30, ( PY1 =:= (Row + 1) * 30 + 50 -> send(P, slot, state, in_tube), NumTube is round((PX - 228 + Row * 20) / 40), tubes(ChTubes), get(ChTubes, find, message(@prolog, same_value,@arg1?indice, NumTube), Tube), send(Tube, add_ball), get(Tube, slot, balls, Balls), Max_descent is 600 - Balls * 20, send(P, slot, max_descent, Max_descent), send(P, slot, position, point(PX, PY)) ; send(P, choose_dir), send(P, slot, angle, Ang2), send(P, slot, pin, point(PX, PY1))).
move_ball_in_tube(P) :-> get(P, slot, position, Descente), get(Descente, x, PX1), get(Descente, y, PY), PY1 is PY+4, send(P, geometry, x := PX1, y := PY1), get(P, slot, max_descent, Max_descent), ( Max_descent =< PY1 -> send(P?mytimer, stop), ( stop(@off) -> send(@prolog, next_ball); true) ; send(P, slot, position, point(PX1, PY1))), send(P?window, display, P).
- - pce_end_class.
next_ball :-
retract(balls(Balls, D)),
new(B, ball(D)),
send(Balls, append, B),
assert(balls(Balls, D)).
% test to find the appropriate tube same_value(V, V).
display_pins(D) :- row(Row), forall(between(0, Row, I), ( Start is 250 - I * 20, Y is I * 30 + 50, forall(between(0, I, J), ( X is Start + J * 40, new(P, pin(point(X,Y))), send(D, display, P))))).
display_tubes(D, Ch) :- row(Row), Row1 is Row+1, forall(between(0, Row1, I), ( new(T, tube(I, D)), send(Ch, append, T), send(D, display, T))). </lang>
PureBasic
<lang purebasic>Global pegRadius, pegSize, pegSize2, height, width, delay, histogramSize, ball
Procedure eventLoop()
Protected event Repeat event = WindowEvent() If event = #PB_Event_CloseWindow End EndIf Until event = 0
EndProcedure
Procedure animate_actual(x1, y1, x2, y2, steps)
Protected x.f, y.f, xstep.f, ystep.f, i, lastX.f, lastY.f x = x1 y = y1 xstep = (x2 - x1)/steps ystep = (y2 - y1)/steps For i = 1 To steps lastX = x lastY = y StartDrawing(CanvasOutput(0)) DrawingMode(#PB_2DDrawing_XOr) Circle(x, y, pegRadius, RGB(0, 255, 255)) StopDrawing() eventLoop() Delay(delay) ; wait in ms StartDrawing(CanvasOutput(0)) DrawingMode(#PB_2DDrawing_XOr) Circle(x, y, pegRadius, RGB(0, 255, 255)) StopDrawing() eventLoop() x + xstep y + ystep Next
EndProcedure
Procedure draw_ball(xpos, ypos)
Static Dim ballcounts(0) ;tally drop positions If xpos > ArraySize(ballcounts()) Redim ballcounts(xpos) EndIf ballcounts(xpos) + 1 animate_actual(xpos, ypos, xpos, height - ballcounts(xpos) * pegSize, 20) StartDrawing(CanvasOutput(0)) Circle(xpos, height - ballcounts(xpos) * pegSize, pegRadius, RGB(255, 0, 0)) StopDrawing() eventLoop() If ballcounts(xpos) <= histogramSize ProcedureReturn 1 EndIf SetWindowTitle(0, "Ended after " + Str(ball) + " balls") ;histogramSize exceeded
EndProcedure
Procedure animate(x1, y1, x2, y2)
animate_actual(x1, y1, x2, y1, 4) animate_actual(x2, y1, x2, y2, 10)
EndProcedure
Procedure galton(pegRows)
;drop a ball into the galton box Protected xpos, ypos, i, oldX, oldY
oldX = width / 2 - pegSize / 2 xpos = oldX oldY = pegSize ypos = oldY animate_actual(oldX, 0, xpos, ypos, 10) For i = 1 To pegRows If Random(1) xpos + pegSize Else xpos - pegSize EndIf ypos + pegSize2 animate(oldX, oldY, xpos, ypos) oldX = xpos oldY = ypos Next ProcedureReturn draw_ball(xpos, ypos)
EndProcedure
Procedure setup_window(numRows, ballCount)
;Draw numRows levels of pegs Protected xpos, ypos, i, j width = (2 * numRows + 2) * pegSize histogramSize = (ballCount + 2) / 3 If histogramSize > 500 / pegSize: histogramSize = 500 / pegSize: EndIf height = width + histogramSize * pegSize OpenWindow(0, 0, 0, width, height, "Galton box animation", #PB_Window_SystemMenu) CanvasGadget(0, 0, 0, width, height) StartDrawing(CanvasOutput(0)) Box(0, 0, width, height, RGB($EB, $EB, $EB)) For i = 1 To numRows ypos = i * pegSize2 xpos = width / 2 - (i - 1) * pegSize - pegSize / 2 For j = 1 To i Circle(xpos, ypos, pegRadius, RGB(0, 0, 255)) xpos + pegSize2 Next Next For i = 1 To numRows Line((numRows - i + 1) * pegSize2 - pegSize / 2, width - pegSize, 1, histogramSize * pegSize, 0) Next StopDrawing()
EndProcedure
- based on the galton box simulation from Unicon book
Define pegRows = 10, ballCount pegRadius = 4 pegSize = pegRadius * 2 + 1 pegSize2 = pegSize * 2 delay = 2 ; ms delay
Repeat
ballCount = Val(InputRequester("Galton box simulator","How many balls to drop?", "100"))
Until ballCount > 0
setup_window(pegRows, ballCount) eventLoop() For ball = 1 To ballCount
If Not galton(pegRows): Break: EndIf
Next Repeat: eventLoop(): ForEver</lang>
Racket
This does not use the default #lang racket. Required is advanced student with teachpacks universe and image. Multiple balls are added each step, but they do not collide.
<lang Racket>
- a ball's position...row is a natural number and col is an integer where 0 is the center
(define-struct pos (row col))
- state of simulation...list of all positions and vector of balls (index = bin)
(define-struct st (poss bins))
- increment vector @i
(define (vector-inc! v i) (vector-set! v i (add1 (vector-ref v i))))
(define BALL-RADIUS 6)
- for balls to fit perfectly between diamond-shaped pins, the side length is
- determined by inscribing the diamond in the circle
(define PIN-SIDE-LENGTH (* (sqrt 2) BALL-RADIUS))
- ultimate pin width and height
(define PIN-WH (* 2 BALL-RADIUS)) (define PIN-HOR-SPACING (* 2 PIN-WH))
- vertical space is the height of an equilateral triangle with side length = PIN-HOR-SPACING
(define PIN-VER-SPACING (* 1/2 (sqrt 3) PIN-HOR-SPACING))
- somewhat copying BASIC256's graphics
- determines how thick the outline will be
(define FILL-RATIO 0.7)
- freeze is a function that converts the drawing code into an actual bitmap forever
(define PIN (freeze (overlay (rotate 45 (square (* FILL-RATIO PIN-SIDE-LENGTH) "solid" "purple"))
(rotate 45 (square PIN-SIDE-LENGTH "solid" "magenta")))))
(define BALL (freeze (overlay (circle (* FILL-RATIO BALL-RADIUS) "solid" "green")
(circle BALL-RADIUS "solid" "dark green"))))
(define BIN-COLOR (make-color 255 128 192))
- balls bin can fit
(define BIN-CAPACITY 10) (define BIN-HEIGHT (* BIN-CAPACITY PIN-WH)) (define BIN (freeze (beside/align "bottom"
(line 0 BIN-HEIGHT BIN-COLOR) (line PIN-WH 0 BIN-COLOR) (line 0 BIN-HEIGHT BIN-COLOR))))
(define draw-background
(let ([background #f]) (λ (height) (if (image? background) background (let* ([w (+ (image-width BIN) (* PIN-HOR-SPACING height))] [h (+ PIN-WH (image-height BIN) (* PIN-VER-SPACING height))] [draw-background (λ () (rectangle w h "solid" "black"))]) (begin (set! background (freeze (draw-background))) background))))))
- draws images using x horizontal space between center points
(define (spaced/x x is)
(if (null? is) (empty-scene 0 0) (let spaced/x ([n 1] [i (car is)] [is (cdr is)]) (if (null? is) i (overlay/xy i (* -1 n x) 0 (spaced/x (add1 n) (car is) (cdr is)))))))
(define (draw-pin-row r) (spaced/x PIN-HOR-SPACING (make-list (add1 r) PIN)))
- draws all pins, using saved bitmap for efficiency
(define draw-pins
(let ([bmp #f]) (λ (height) (let ([draw-pins (λ () (foldl (λ (r i) (overlay/align/offset ;vertically line up all pin rows "center" "bottom" (draw-pin-row r) ;shift down from the bottom of accum'ed image by ver spacing 0 (- PIN-VER-SPACING) i)) (draw-pin-row 0) (range 1 height 1)))]) (if (image? bmp) bmp (begin (set! bmp (freeze (draw-pins))) bmp))))))
(define (draw-ball p i)
;the ball starts at the top of the image (overlay/align/offset "center" "top" BALL (* -1 (pos-col p) PIN-WH) (* -1 (pos-row p) PIN-VER-SPACING) i))
- bin has balls added from bottom, stacked exactly on top of each other
- the conditional logic is needed because above can't handle 0 or 1 things
(define (draw-bin n)
(if (zero? n) BIN (overlay/align "center" "bottom" (if (= n 1) BALL (apply above (make-list n BALL))) BIN)))
- main drawing function
(define (draw height s)
(let* ([bins (spaced/x PIN-HOR-SPACING (map draw-bin (vector->list (st-bins s))))] ;pins above bins [w/pins (above (draw-pins height) bins)] ;draw this all one ball diameter (PIN-WH) below top [w/background (overlay/align/offset "center" "top" w/pins 0 (- PIN-WH) (draw-background height))]) ;now accumulate in each ball (foldl draw-ball w/background (st-poss s))))
- a ball moves down by increasing its row and randomly changing its col by -1 or 1
(define (next-row height p)
(make-pos (add1 (pos-row p)) (+ -1 (* 2 (random 2)) (pos-col p))))
- each step, every ball goes to the next row and new balls are added at the top center
- balls that fall off go into bins
(define (tock height s)
(let* ([new-ps (map (λ (p) (next-row height p)) (st-poss s))] ;live balls haven't gone past the last row of pins [live (filter (λ (p) (< (pos-row p) height)) new-ps)] ;dead balls have (partition from normal Racket would be useful here...) [dead (filter (λ (p) (>= (pos-row p) height)) new-ps)] ;adjust col from [-x,x] to [0,2x] [bin-indices (map (λ (p) (quotient (+ (pos-col p) height) 2)) dead)]) ;add new balls to the live balls (make-st (append (make-list (random 4) (make-pos 0 0)) live) ;sum dead ball positions into bins (begin (for-each (λ (i) (vector-inc! (st-bins s) i)) bin-indices) (st-bins s)))))
- run simulation with empty list of positions to start, stepping with "tock" and drawing with "draw"
(define (run height)
(big-bang (make-st '() (make-vector (add1 height) 0)) (on-tick (λ (ps) (tock height ps)) 0.5) (to-draw (λ (ps) (draw height ps)))))
</lang>
Ruby
<lang ruby>$rows_of_pins = 12 $width = $rows_of_pins * 10 + ($rows_of_pins+1)*14
Shoes.app(
:width => $width + 14, :title => "Galton Box"
) do
@bins = Array.new($rows_of_pins+1, 0)
@x_coords = Array.new($rows_of_pins) {Array.new} @y_coords = Array.new($rows_of_pins) stack(:width => $width) do stroke gray fill gray 1.upto($rows_of_pins) do |row| y = 14 + 24*row @y_coords[row-1] = y row.times do |i| x = $width / 2 + (i - 0.5*row)*24 + 14 @x_coords[row-1] << x oval x+2, y, 6 end end end @y_coords << @y_coords[-1] + 24 @x_coords << @x_coords[-1].map {|x| x-12} + [@x_coords[-1][-1]+12]
@balls = stack(:width => $width) do stroke red fill red end.move(0,0)
@histogram = stack(:width => $width) do nostroke fill black end.move(0, @y_coords[-1] + 10)
@paused = false keypress do |key| case key when "\x11", :control_q exit when "\x10", :control_p @paused = !@paused end end
@ball_row = 0 @ball_col = 0 animate(2*$rows_of_pins) do if not @paused y = @y_coords[@ball_row] - 12 x = @x_coords[@ball_row][@ball_col] @balls.clear {oval x, y, 10} @ball_row += 1 if @ball_row <= $rows_of_pins @ball_col += 1 if rand >= 0.5 else @bins[@ball_col] += 1 @ball_row = @ball_col = 0 update_histogram end end end
def update_histogram y = @y_coords[-1] + 10 @histogram.clear do @bins.each_with_index do |num, i| if num > 0 x = @x_coords[-1][i] rect x-6, 0, 24, num end end end end
end</lang>
Tcl
<lang tcl>package require Tcl 8.6
oo::class create GaltonBox {
variable b w h n x y cnt step dropping
constructor {BALLS {NUMPEGS 5} {HEIGHT 24}} {
set n $NUMPEGS set w [expr {$n*2 + 1}] set h $HEIGHT puts -nonewline "\033\[H\033\[J" set x [set y [lrepeat $BALLS 0]] set cnt 0 set step 0 set dropping 1
set b [lrepeat $h [lrepeat $w " "]] for {set i 0} {$i < $n} {incr i} { for {set j [expr {-$i}]} {$j <= $i} {incr j 2} { lset b [expr {2*$i+2}] [expr {$j+$w/2}] "*" } }
}
method show {} {
puts -nonewline "\033\[H" set oldrow {} foreach row $b { foreach char $row oldchar $oldrow { if {$char ne "*"} { puts -nonewline "$char " } elseif {$oldchar eq " "} { puts -nonewline "\033\[32m*\033\[m " } else { puts -nonewline "\033\[31m*\033\[m " } } set oldrow $row puts "" }
}
method Move idx {
set xx [lindex $x $idx] set yy [lindex $y $idx] set kill 0
if {$yy < 0} {return 0} if {$yy == $h-1} { lset y $idx -1 return 0 }
switch [lindex $b [incr yy] $xx] { "*" { incr xx [expr {2*int(2 * rand()) - 1}] if {[lindex $b [incr yy -1] $xx] ne " "} { set dropping 0 } } "o" { incr yy -1 set kill 1 } }
set c [lindex $b [lindex $y $idx] [lindex $x $idx]] lset b [lindex $y $idx] [lindex $x $idx] " " lset b $yy $xx $c if {$kill} { lset y $idx -1 } else { lset y $idx $yy } lset x $idx $xx return [expr {!$kill}]
}
method step {} {
set moving 0 for {set i 0} {$i < $cnt} {incr i} { set moving [expr {[my Move $i] || $moving}] } if {2 == [incr step] && $cnt < [llength $x] && $dropping} { set step 0 lset x $cnt [expr {$w / 2}] lset y $cnt 0 if {[lindex $b [lindex $y $cnt] [lindex $x $cnt]] ne " "} { return 0 } lset b [lindex $y $cnt] [lindex $x $cnt] "o" incr cnt } return [expr {($moving || $dropping)}]
}
}
GaltonBox create board 1024 {*}$argv while true {
board show if {[board step]} {after 60} break
}</lang> After a sample run with input parameters 10 55:
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * o o * * * * * o * o * * * * o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o
There is a much more comprehensive solution to this on the Tcler's Wiki.
XPL0
This Peeks into some IBM-PC specific locations and hence is not entirely portable.
<lang XPL0>include c:\cxpl\codes; \intrinsic code declarations define Balls = 80; \maximum number of balls int Bx(Balls), By(Balls), \character cell coordinates of each ball
W, I, J, Peg, Dir;
[W:= Peek($40, $4A); \get screen width in characters Clear; CrLf(6); CrLf(6); for Peg:= 1 to 10 do \draw pegs
[for I:= 1 to 12-Peg do ChOut(6,^ ); \space over to first peg for I:= 1 to Peg do [ChOut(6,^.); ChOut(6,^ )]; CrLf(6); ];
for J:= 0 to 12-1 do \draw slots
[for I:= 0 to 12-1 do [ChOut(6,^:); ChOut(6,^ )]; CrLf(6); ];
for I:= 0 to 23-1 do ChOut(6,^.); \draw bottom for I:= 0 to Balls-1 do \make source of balls at top
[Bx(I):= 11; By(I):= 1];
Attrib($C); \make balls bright red repeat \balls away! ...
for I:= 0 to Balls-1 do \for all the balls ... [Cursor(Bx(I), By(I)); ChOut(6, ^ ); \erase ball's initial position if Peek($B800, (Bx(I)+(By(I)+1)*W)*2) = ^ \is ball above empty location? then By(I):= By(I)+1 \yes: fall straight down else [Dir:= Ran(3)-1; \no: randomly fall right or left if Peek($B800, (Bx(I)+Dir+(By(I)+1)*W)*2) = ^ then [Bx(I):= Bx(I)+Dir; By(I):= By(I)+1]; ]; Cursor(Bx(I), By(I)); ChOut(6, ^o); \draw ball at its new position ]; Sound(0, 3, 1); \delay about 1/6 second
until KeyHit; \continue until a key is struck ]</lang>
- Output:
o o. .o. . .o. .o. . . . .o. . . . .o. . . . . .o. . .o. . . . .o. . . . . . . . . . .o. . . . . . . .o. .o. . . : : : : : : : : : : : : : : : : :o: : : : : : : : : : :o: : : : : : : : : : : : : : : : : : : : : : : : :o: : : : : : : : : : : : : : :o: : : : : : : : : :o: : : : : : : : :o: : :o: : : :o: : : : : : : :o:o: : : : : : : : : :o:o:o: : : : : : : : : :o:o:o: : : : : : : :o:o:o:o:o:o: : : : .......................