⚠️ Warning: This is a draft ⚠️
This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.
If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.
{{task}}
The [[wp:Chaos_game|Chaos Game]] is a method of generating the attractor of an iterated function system (IFS). One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
;Task Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a starting point at random (preferably inside the triangle). Then add the next point halfway between the starting point and one of the reference points. This reference point is chosen at random.
After a sufficient number of iterations, the image of a Sierpinski Triangle should emerge.
;See also
- [http://www.geoastro.de/ChaosSpiel/ChaosEnglish.html The Game of Chaos]
BASIC
This should require minimal adaptation to work with any of the older Microsoft-style BASICs. Users of other dialects will need to replace lines 10 and 150 with the appropriate statements to select a graphics output mode (if necessary) and to plot a pixel at x,y in colour v; they should also add LET throughout and 170 END if their dialects require those things.
10 SCREEN 1
20 X = INT(RND(0) * 200)
30 Y = INT(RND(0) * 173)
40 FOR I=1 TO 20000
50 V = INT(RND(0) * 3) + 1
60 ON V GOTO 70,100,130
70 X = X/2
80 Y = Y/2
90 GOTO 150
100 X = 100 + (100-X)/2
110 Y = 173 - (173-Y)/2
120 GOTO 150
130 X = 200 - (200-X)/2
140 Y = Y/2
150 PSET X,Y,V
160 NEXT I
=
Applesoft BASIC
= Adapted from the code given above.
10 HGR2
20 X = INT(RND(1) * 200)
30 Y = INT(RND(1) * 173)
40 FOR I=1 TO 20000
50 V = INT(RND(1) * 3) + 1
60 ON V GOTO 70,100,130
70 X = X/2
80 Y = Y/2
90 GOTO 150
100 X = 100 + (100-X)/2
110 Y = 173 - (173-Y)/2
120 GOTO 150
130 X = 200 - (200-X)/2
140 Y = Y/2
150 HCOLOR=V+4
160 HPLOT X,Y
170 NEXT I
=
BASIC256
=
#Chaos game
ancho = 500 : alto = 300
x = Int(Rand * ancho)
y = Int(Rand * alto)
Clg
FastGraphics
Graphsize ancho , alto
For iteracion = 1 To 30000
vertice = Int(Rand * 3) + 1
Begin Case
Case vertice = 1
x = x / 2
y = y / 2
Color red
Case vertice = 2
x = (ancho/2) + ((ancho/2)-x) / 2
y = alto - (alto-y) / 2
Color green
Case vertice = 3
x = ancho - (ancho-x) / 2
y = y / 2
Color blue
End Case
#Pset (x,y),vertice
Plot (x,y)
Next iteracion
Refresh
ImgSave "chaos_game.jpg", "jpg"
End
=
Sinclair ZX81 BASIC
=
Adapted from the other BASIC versions. Monochrome and low-resolution, of course. Works with only 1k of RAM. If you like, you can try changing line 30 to go round the loop a different number of times.
Note that ZX81 BASIC does not have an explicit computed GOTO; we can, however, actually compute the value of an expression and then GOTO it as a line number.
10 LET X=RND*46
20 LET Y=RND*40
30 FOR I=1 TO 5000
40 LET VERTEX=INT (RND*3)
50 GOTO 60+VERTEX*30
60 LET X=X/2
70 LET Y=Y/2
80 GOTO 140
90 LET X=23+(23-X)/2
100 LET Y=40-(40-Y)/2
110 GOTO 140
120 LET X=46-(46-X)/2
130 LET Y=Y/2
140 PLOT X,42-Y
150 NEXT I
{{out}} Screenshot [http://www.edmundgriffiths.com/zx81chaosgame.jpg here]. As with most ZX81 graphics, you can obtain the very best results by making it quite small and looking at it from a long way away.
=
ZX Spectrum Basic
=
The final INK statement sets the foreground colour back to black.
10 LET x=RND*200
20 LET y=RND*173
30 FOR i=1 TO 20000
40 LET vertex=INT (RND*3)
50 IF vertex=1 THEN GO TO 100
60 IF vertex=2 THEN GO TO 130
70 LET x=x/2
80 LET y=y/2
90 GO TO 150
100 LET x=100+(100-x)/2
110 LET y=173-(173-y)/2
120 GO TO 150
130 LET x=200-(200-x)/2
140 LET y=y/2
150 INK vertex+1
160 PLOT x,y
170 NEXT i
180 INK 0
C
Interactive code which asks the side length of the starting triangle and number of iterations as inputs, a larger number of iterations produces a more accurate approximation of the Sierpinski fractal. Requires the [http://www.cs.colorado.edu/~main/bgi/cs1300/ WinBGIm] library.
#include<graphics.h> #include<stdlib.h> #include<stdio.h> #include<math.h> #include<time.h> #define pi M_PI int main(){ time_t t; double side, vertices[3][3],seedX,seedY,windowSide; int i,iter,choice; printf("Enter triangle side length : "); scanf("%lf",&side); printf("Enter number of iterations : "); scanf("%d",&iter); windowSide = 10 + 2*side; initwindow(windowSide,windowSide,"Sierpinski Chaos"); for(i=0;i<3;i++){ vertices[i][0] = windowSide/2 + side*cos(i*2*pi/3); vertices[i][1] = windowSide/2 + side*sin(i*2*pi/3); putpixel(vertices[i][0],vertices[i][1],15); } srand((unsigned)time(&t)); seedX = rand()%(int)(vertices[0][0]/2 + (vertices[1][0] + vertices[2][0])/4); seedY = rand()%(int)(vertices[0][1]/2 + (vertices[1][1] + vertices[2][1])/4); putpixel(seedX,seedY,15); for(i=0;i<iter;i++){ choice = rand()%3; seedX = (seedX + vertices[choice][0])/2; seedY = (seedY + vertices[choice][1])/2; putpixel(seedX,seedY,15); } getch(); closegraph(); return 0; }
C++
This program will generate the Sierpinski Triangle and save it to your hard drive.
#include <windows.h> #include <ctime> #include <string> #include <iostream> const int BMP_SIZE = 600; class myBitmap { public: myBitmap() : pen( NULL ), brush( NULL ), clr( 0 ), wid( 1 ) {} ~myBitmap() { DeleteObject( pen ); DeleteObject( brush ); DeleteDC( hdc ); DeleteObject( bmp ); } bool create( int w, int h ) { BITMAPINFO bi; ZeroMemory( &bi, sizeof( bi ) ); bi.bmiHeader.biSize = sizeof( bi.bmiHeader ); bi.bmiHeader.biBitCount = sizeof( DWORD ) * 8; bi.bmiHeader.biCompression = BI_RGB; bi.bmiHeader.biPlanes = 1; bi.bmiHeader.biWidth = w; bi.bmiHeader.biHeight = -h; HDC dc = GetDC( GetConsoleWindow() ); bmp = CreateDIBSection( dc, &bi, DIB_RGB_COLORS, &pBits, NULL, 0 ); if( !bmp ) return false; hdc = CreateCompatibleDC( dc ); SelectObject( hdc, bmp ); ReleaseDC( GetConsoleWindow(), dc ); width = w; height = h; return true; } void clear( BYTE clr = 0 ) { memset( pBits, clr, width * height * sizeof( DWORD ) ); } void setBrushColor( DWORD bClr ) { if( brush ) DeleteObject( brush ); brush = CreateSolidBrush( bClr ); SelectObject( hdc, brush ); } void setPenColor( DWORD c ) { clr = c; createPen(); } void setPenWidth( int w ) { wid = w; createPen(); } void saveBitmap( std::string path ) { BITMAPFILEHEADER fileheader; BITMAPINFO infoheader; BITMAP bitmap; DWORD wb; GetObject( bmp, sizeof( bitmap ), &bitmap ); DWORD* dwpBits = new DWORD[bitmap.bmWidth * bitmap.bmHeight]; ZeroMemory( dwpBits, bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ) ); ZeroMemory( &infoheader, sizeof( BITMAPINFO ) ); ZeroMemory( &fileheader, sizeof( BITMAPFILEHEADER ) ); infoheader.bmiHeader.biBitCount = sizeof( DWORD ) * 8; infoheader.bmiHeader.biCompression = BI_RGB; infoheader.bmiHeader.biPlanes = 1; infoheader.bmiHeader.biSize = sizeof( infoheader.bmiHeader ); infoheader.bmiHeader.biHeight = bitmap.bmHeight; infoheader.bmiHeader.biWidth = bitmap.bmWidth; infoheader.bmiHeader.biSizeImage = bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ); fileheader.bfType = 0x4D42; fileheader.bfOffBits = sizeof( infoheader.bmiHeader ) + sizeof( BITMAPFILEHEADER ); fileheader.bfSize = fileheader.bfOffBits + infoheader.bmiHeader.biSizeImage; GetDIBits( hdc, bmp, 0, height, ( LPVOID )dwpBits, &infoheader, DIB_RGB_COLORS ); HANDLE file = CreateFile( path.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL ); WriteFile( file, &fileheader, sizeof( BITMAPFILEHEADER ), &wb, NULL ); WriteFile( file, &infoheader.bmiHeader, sizeof( infoheader.bmiHeader ), &wb, NULL ); WriteFile( file, dwpBits, bitmap.bmWidth * bitmap.bmHeight * 4, &wb, NULL ); CloseHandle( file ); delete [] dwpBits; } HDC getDC() const { return hdc; } int getWidth() const { return width; } int getHeight() const { return height; } private: void createPen() { if( pen ) DeleteObject( pen ); pen = CreatePen( PS_SOLID, wid, clr ); SelectObject( hdc, pen ); } HBITMAP bmp; HDC hdc; HPEN pen; HBRUSH brush; void *pBits; int width, height, wid; DWORD clr; }; class chaos { public: void start() { POINT org; fillPts(); initialPoint( org ); initColors(); int cnt = 0, i; bmp.create( BMP_SIZE, BMP_SIZE ); bmp.clear( 255 ); while( cnt++ < 1000000 ) { switch( rand() % 6 ) { case 0: case 3: i = 0; break; case 1: case 5: i = 1; break; case 2: case 4: i = 2; } setPoint( org, myPoints[i], i ); } // --- edit this path --- // bmp.saveBitmap( "F:/st.bmp" ); } private: void setPoint( POINT &o, POINT v, int i ) { POINT z; o.x = ( o.x + v.x ) >> 1; o.y = ( o.y + v.y ) >> 1; SetPixel( bmp.getDC(), o.x, o.y, colors[i] ); } void fillPts() { int a = BMP_SIZE - 1; myPoints[0].x = BMP_SIZE >> 1; myPoints[0].y = 0; myPoints[1].x = 0; myPoints[1].y = myPoints[2].x = myPoints[2].y = a; } void initialPoint( POINT& p ) { p.x = ( BMP_SIZE >> 1 ) + rand() % 2 ? rand() % 30 + 10 : -( rand() % 30 + 10 ); p.y = ( BMP_SIZE >> 1 ) + rand() % 2 ? rand() % 30 + 10 : -( rand() % 30 + 10 ); } void initColors() { colors[0] = RGB( 255, 0, 0 ); colors[1] = RGB( 0, 255, 0 ); colors[2] = RGB( 0, 0, 255 ); } myBitmap bmp; POINT myPoints[3]; COLORREF colors[3]; }; int main( int argc, char* argv[] ) { srand( ( unsigned )time( 0 ) ); chaos c; c.start(); return 0; }
C#
using System.Diagnostics; using System.Drawing; namespace RosettaChaosGame { class Program { static void Main(string[] args) { var bm = new Bitmap(600, 600); var referencePoints = new Point[] { new Point(0, 600), new Point(600, 600), new Point(300, 81) }; var r = new System.Random(); var p = new Point(r.Next(600), r.Next(600)); for (int count = 0; count < 10000; count++) { bm.SetPixel(p.X, p.Y, Color.Magenta); int i = r.Next(3); p.X = (p.X + referencePoints[i].X) / 2; p.Y = (p.Y + referencePoints[i].Y) / 2; } const string filename = "Chaos Game.png"; bm.Save(filename); Process.Start(filename); } } }
Common Lisp
{{libheader|opticl}}
(defpackage #:chaos (:use #:cl #:opticl)) (in-package #:chaos) (defparameter *image-size* 600) (defparameter *margin* 50) (defparameter *edge-size* (- *image-size* *margin* *margin*)) (defparameter *iterations* 1000000) (defun chaos () (let ((image (make-8-bit-rgb-image *image-size* *image-size* :initial-element 255)) (a (list (- *image-size* *margin*) *margin*)) (b (list (- *image-size* *margin*) (- *image-size* *margin*))) (c (list (- *image-size* *margin* (round (* (tan (/ pi 3)) *edge-size*) 2)) (round *image-size* 2))) (point (list (+ (random *edge-size*) *margin*) (+ (random *edge-size*) *margin*)))) (dotimes (i *iterations*) (let ((ref (ecase (random 3) (0 a) (1 b) (2 c)))) (setf point (list (round (+ (first point) (first ref)) 2) (round (+ (second point) (second ref)) 2)))) (setf (pixel image (first point) (second point)) (values 255 0 0))) (write-png-file "chaos.png" image)))
EasyLang
[https://easylang.online/apps/run.html?code=x%5B%5D%20%3D%20%5B%200%20100%2050%20%5D%0Ay%5B%5D%20%3D%20%5B%2093%2093%207%20%5D%0Ac%5B%5D%20%3D%20%5B%20900%20090%20009%20%5D%0Afor%20i%20range%20100000%0Ah%20%3D%20random%203%0Ax%23%20%3D%20%28x%23%20%2B%20x%5Bh%5D%29%20/%202%0Ay%23%20%3D%20%28y%23%20%2B%20y%5Bh%5D%29%20/%202%0Acolor%20c%5Bh%5D%0Amove%20x%23%20y%23%0Arect%200.3%200.3%0A. Run it]
## Fortran
This FORTRAN code creates an output file which can be drawn with gnuplot.
```Fortran
PROGRAM CHAOS
IMPLICIT NONE
REAL, DIMENSION(3):: KA, KN ! Koordinates old/new
REAL, DIMENSION(3):: DA, DB, DC ! Triangle
INTEGER:: I, Z
INTEGER, PARAMETER:: UT = 17
! Define corners of triangle
DA = (/ 0., 0., 0. /)
DB = (/ 600., 0., 0. /)
DC = (/ 500., 0., 400. /)
! Define starting point
KA = (/ 500., 0., 100. /)
OPEN (UNIT = UT, FILE = 'aus.csv')
DO I=1, 1000000
Z = ZAHL()
WRITE (UT, '(3(F12.6, ";"))') KA
SELECT CASE (Z)
CASE (1)
CALL MITTELP(KA, DA, KN)
CASE (2)
CALL MITTELP(KA, DB, KN)
CASE (3)
CALL MITTELP(KA, DC, KN)
END SELECT
KA = KN
END DO
CLOSE (UT)
CONTAINS
! Calculates center of two points
SUBROUTINE MITTELP(P1, P2, MP)
REAL, INTENT(IN), DIMENSION(3):: P1, P2
REAL, INTENT(OUT), DIMENSION(3):: MP
MP = (P1 + P2) / 2.
END SUBROUTINE MITTELP
! Returns random number
INTEGER FUNCTION ZAHL()
REAL:: ZZ
CALL RANDOM_NUMBER(ZZ)
ZZ = ZZ * 3.
ZAHL = FLOOR(ZZ) + 1
IF (ZAHL .GT. 3) ZAHL = 3
END FUNCTION ZAHL
END PROGRAM CHAOS
Gnuplot Code to draw file:
set terminal jpeg enhanced size 1600,960
set output 'chaos.jpg'
set nokey
set style line 1 lc rgb '#0060ad' lt 1 lw 3 pt 7 ps 0.3
plot 'aus.csv' using 1:3 with points ls 1 notitle
FreeBASIC
{{trans|BASIC256}}
' Chaos game
Const ancho = 320, alto = 240
Dim As Integer x, y, iteracion, vertice
x = Int(Rnd * ancho)
y = Int(Rnd * alto)
Screenres ancho, alto, 8
Cls
For iteracion = 1 To 30000
vertice = Int(Rnd * 3) + 1
Select Case vertice
Case 1
x = x / 2
y = y / 2
vertice = 4 'red
Case 2
x = (ancho/2) + ((ancho/2)-x) / 2
y = alto - (alto-y) / 2
vertice = 2 'green
Case 3
x = ancho - (ancho-x) / 2
y = y / 2
vertice = 1 'blue
End Select
Pset (x,y),vertice
Next iteracion
Sleep
End
Go
This writes a simple GIF animation of the method.
package main import ( "fmt" "image" "image/color" "image/draw" "image/gif" "log" "math" "math/rand" "os" "time" ) var bwPalette = color.Palette{ color.Transparent, color.White, color.RGBA{R: 0xff, A: 0xff}, color.RGBA{G: 0xff, A: 0xff}, color.RGBA{B: 0xff, A: 0xff}, } func main() { const ( width = 160 frames = 100 pointsPerFrame = 50 delay = 100 * time.Millisecond filename = "chaos_anim.gif" ) var tan60 = math.Sin(math.Pi / 3) height := int(math.Round(float64(width) * tan60)) b := image.Rect(0, 0, width, height) vertices := [...]image.Point{ {0, height}, {width, height}, {width / 2, 0}, } // Make a filled triangle. m := image.NewPaletted(b, bwPalette) for y := b.Min.Y; y < b.Max.Y; y++ { bg := int(math.Round(float64(b.Max.Y-y) / 2 / tan60)) for x := b.Min.X + bg; x < b.Max.X-bg; x++ { m.SetColorIndex(x, y, 1) } } // Pick starting point var p image.Point rand.Seed(time.Now().UnixNano()) p.Y = rand.Intn(height) + b.Min.Y p.X = rand.Intn(width) + b.Min.X // TODO: make within triangle anim := newAnim(frames, delay) addFrame(anim, m) for i := 1; i < frames; i++ { for j := 0; j < pointsPerFrame; j++ { // Pick a random vertex vi := rand.Intn(len(vertices)) v := vertices[vi] // Move p halfway there p.X = (p.X + v.X) / 2 p.Y = (p.Y + v.Y) / 2 m.SetColorIndex(p.X, p.Y, uint8(2+vi)) } addFrame(anim, m) } if err := writeAnim(anim, filename); err != nil { log.Fatal(err) } fmt.Printf("wrote to %q\n", filename) } // Stuff for making a simple GIF animation. func newAnim(frames int, delay time.Duration) *gif.GIF { const gifDelayScale = 10 * time.Millisecond g := &gif.GIF{ Image: make([]*image.Paletted, 0, frames), Delay: make([]int, 1, frames), } g.Delay[0] = int(delay / gifDelayScale) return g } func addFrame(anim *gif.GIF, m *image.Paletted) { b := m.Bounds() dst := image.NewPaletted(b, m.Palette) draw.Draw(dst, b, m, image.ZP, draw.Src) anim.Image = append(anim.Image, dst) if len(anim.Delay) < len(anim.Image) { anim.Delay = append(anim.Delay, anim.Delay[0]) } } func writeAnim(anim *gif.GIF, filename string) error { f, err := os.Create(filename) if err != nil { return err } err = gif.EncodeAll(f, anim) if cerr := f.Close(); err == nil { err = cerr } return err }
Gnuplot
{{trans|PARI/GP}} {{Works with|gnuplot|5.0 (patchlevel 3) and above}} [[File:ChGS3Gnu1.png|right|thumb|Output ChGS3Gnu1.png]]
## Chaos Game (Sierpinski triangle) 2/16/17 aev
reset
fn="ChGS3Gnu1"; clr='"red"';
ttl="Chaos Game (Sierpinski triangle)"
sz=600; sz1=sz/2; sz2=sz1*sqrt(3);
x=y=xf=yf=v=0;
dfn=fn.".dat"; ofn=fn.".png";
set terminal png font arial 12 size 640,640
set print dfn append
set output ofn
unset border; unset xtics; unset ytics; unset key;
set size square
set title ttl font "Arial:Bold,12"
lim=30000; max=100; x=y=xw=yw=p=0;
randgp(top) = floor(rand(0)*top)
x=randgp(sz); y=randgp(sz2);
do for [i=1:lim] {
v=randgp(3);
if (v==0) {x=x/2; y=y/2}
if (v==1) {x=sz1+(sz1-x)/2; y=sz2-(sz2-y)/2}
if (v==2) {x=sz-(sz-x)/2; y=y/2}
xf=floor(x); yf=floor(y);
if(!(xf<1||xf>sz||yf<1||yf>sz)) {print xf," ",yf};
}
plot dfn using 1:2 with points pt 7 ps 0.5 lc @clr
set output
unset print
{{Output}}
File: ChGS3Gnu1.png
Haskell
import Control.Monad (replicateM) import Control.Monad.Random (fromList) type Point = (Float,Float) type Transformations = [(Point -> Point, Float)] -- weighted transformations -- realization of the game for given transformations gameOfChaos :: MonadRandom m => Int -> Transformations -> Point -> m [Point] gameOfChaos n transformations x = iterateA (fromList transformations) x where iterateA f x = scanr ($) x <$> replicateM n f
Some transformations:
-- the Sierpinsky`s triangle triangle = [ (mid (0, 0), 1) , (mid (1, 0), 1) , (mid (0.5, 0.86), 1) ] where mid (a,b) (x,y) = ((a+x)/2, (b+y)/2) -- the Barnsley's fern fern = [(f1, 1), (f2, 85), (f3, 7), (f4, 7)] where f1 (x,y) = (0, 0.16*y) f2 (x,y) = (0.85*x + 0.04*y, -0.04*x + 0.85*y + 1.6) f3 (x,y) = (0.2*x - 0.26*y, 0.23*x + 0.22*y + 1.6) f4 (x,y) = (-0.15*x + 0.28*y, 0.26*x + 0.24*y + 0.44) -- A dragon curve dragon = [(f1, 1), (f2, 1)] where f1 (x,y) = (0.5*x - 0.5*y, 0.5*x + 0.5*y) f2 (x,y) = (-0.5*x + 0.5*y+1, -0.5*x - 0.5*y)
Drawing the result:
import Control.Monad.Random (getRandomR) import Graphics.Gloss main = do x <- getRandomR (0,1) y <- getRandomR (0,1) pts <- gameOfChaos 500000 triangle (x,y) display window white $ foldMap point pts where window = InWindow "Game of Chaos" (400,400) (0,0) point (x,y) = translate (100*x) (100*y) $ circle 0.02
J
[[File:j_chaos_game.png|300px|thumb|right]]
Note 'plan, Working in complex plane'
Make an equilateral triangle.
Make a list of N targets
Starting with a random point near the triangle,
iteratively generate new points.
plot the new points.
j has a particularly rich notation for numbers.
1ad_90 specifies a complex number with radius 1
at an angle of negative 90 degrees.
2p1 is 2 times (pi raised to the first power).
)
N=: 3000
require'plot'
TAU=: 2p1 NB. tauday.com
mean=: +/ % #
NB. equilateral triangle with vertices on unit circle
NB. rotated for fun.
TRIANGLE=: *(j./2 1 o.(TAU%6)*?0)*1ad_90 1ad150 1ad30
TARGETS=: (N ?@:# 3) { TRIANGLE
NB. start on unit circle
START=: j./2 1 o.TAU*?0
NEW_POINTS=: (mean@:(, {.) , ])/ TARGETS , START
'marker'plot NEW_POINTS
Java
[[File:chaos_game.png|300px|thumb|right]] {{works with|Java|8}}
import java.awt.*; import java.awt.event.*; import java.util.*; import javax.swing.*; import javax.swing.Timer; public class ChaosGame extends JPanel { class ColoredPoint extends Point { int colorIndex; ColoredPoint(int x, int y, int idx) { super(x, y); colorIndex = idx; } } Stack<ColoredPoint> stack = new Stack<>(); Point[] points = new Point[3]; Color[] colors = {Color.red, Color.green, Color.blue}; Random r = new Random(); public ChaosGame() { Dimension dim = new Dimension(640, 640); setPreferredSize(dim); setBackground(Color.white); int margin = 60; int size = dim.width - 2 * margin; points[0] = new Point(dim.width / 2, margin); points[1] = new Point(margin, size); points[2] = new Point(margin + size, size); stack.push(new ColoredPoint(-1, -1, 0)); new Timer(10, (ActionEvent e) -> { if (stack.size() < 50_000) { for (int i = 0; i < 1000; i++) addPoint(); repaint(); } }).start(); } private void addPoint() { try { int colorIndex = r.nextInt(3); Point p1 = stack.peek(); Point p2 = points[colorIndex]; stack.add(halfwayPoint(p1, p2, colorIndex)); } catch (EmptyStackException e) { System.out.println(e); } } void drawPoints(Graphics2D g) { for (ColoredPoint p : stack) { g.setColor(colors[p.colorIndex]); g.fillOval(p.x, p.y, 1, 1); } } ColoredPoint halfwayPoint(Point a, Point b, int idx) { return new ColoredPoint((a.x + b.x) / 2, (a.y + b.y) / 2, idx); } @Override public void paintComponent(Graphics gg) { super.paintComponent(gg); Graphics2D g = (Graphics2D) gg; g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); drawPoints(g); } public static void main(String[] args) { SwingUtilities.invokeLater(() -> { JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setTitle("Chaos Game"); f.setResizable(false); f.add(new ChaosGame(), BorderLayout.CENTER); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); }); } }
JavaScript
Plots the fractal on an HTML canvas element.
<head>
<meta charset="UTF-8">
<title>Chaos Game</title>
</head>
<body>
<p>
<canvas id="sierpinski" width=400 height=346></canvas>
</p>
<p>
<button onclick="chaosGame()">Click here to see a Sierpiński triangle</button>
</p>
<script>
function chaosGame() {
var canv = document.getElementById('sierpinski').getContext('2d');
var x = Math.random() * 400;
var y = Math.random() * 346;
for (var i=0; i<30000; i++) {
var vertex = Math.floor(Math.random() * 3);
switch(vertex) {
case 0:
x = x / 2;
y = y / 2;
canv.fillStyle = 'green';
break;
case 1:
x = 200 + (200 - x) / 2
y = 346 - (346 - y) / 2
canv.fillStyle = 'red';
break;
case 2:
x = 400 - (400 - x) / 2
y = y / 2;
canv.fillStyle = 'blue';
}
canv.fillRect(x,y, 1,1);
}
}
</script>
</body>
</html>
Julia
{{works with|Julia|0.6}}
using Luxor width = 1000; height = 1000; Drawing(width, height, "./chaos.png"); t = Turtle(0, 0, true, 0, (0., 0., 0.)); x = rand(1:width); y = rand(1:height); for l in 1:30_000 v = rand(1:3); if v == 1 x /= 2; y /= 2; elseif v == 2 x = width/2 + (width/2 - x)/2; y = height - (height - y)/2; else x = width - (width - x)/2; y = y / 2; end Reposition(t, x, height-y); Circle(t, 3); end finish(); preview();
Kotlin
{{trans|Java}}
//Version 1.1.51 import java.awt.* import java.util.Stack import java.util.Random import javax.swing.JPanel import javax.swing.JFrame import javax.swing.Timer import javax.swing.SwingUtilities class ChaosGame : JPanel() { class ColoredPoint(x: Int, y: Int, val colorIndex: Int) : Point(x, y) val stack = Stack<ColoredPoint>() val points: List<Point> val colors = listOf(Color.red, Color.green, Color.blue) val r = Random() init { val dim = Dimension(640, 640) preferredSize = dim background = Color.white val margin = 60 val size = dim.width - 2 * margin points = listOf( Point(dim.width / 2, margin), Point(margin, size), Point(margin + size, size) ) stack.push(ColoredPoint(-1, -1, 0)) Timer(10) { if (stack.size < 50_000) { for (i in 0 until 1000) addPoint() repaint() } }.start() } private fun addPoint() { val colorIndex = r.nextInt(3) val p1 = stack.peek() val p2 = points[colorIndex] stack.add(halfwayPoint(p1, p2, colorIndex)) } fun drawPoints(g: Graphics2D) { for (cp in stack) { g.color = colors[cp.colorIndex] g.fillOval(cp.x, cp.y, 1, 1) } } fun halfwayPoint(a: Point, b: Point, idx: Int) = ColoredPoint((a.x + b.x) / 2, (a.y + b.y) / 2, idx) override fun paintComponent(gg: Graphics) { super.paintComponent(gg) val g = gg as Graphics2D g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON) drawPoints(g) } } fun main(args: Array<String>) { SwingUtilities.invokeLater { val f = JFrame() with (f) { defaultCloseOperation = JFrame.EXIT_ON_CLOSE title = "Chaos Game" isResizable = false add(ChaosGame(), BorderLayout.CENTER) pack() setLocationRelativeTo(null) isVisible = true } } }
{{output}}
Same as Java entry
Logo
to chaosgame :sidelength :iterations
make "width :sidelength
make "height (:sidelength/2 * sqrt 3)
make "x (random :width)
make "y (random :height)
repeat :iterations [
make "vertex (random 3)
if :vertex = 0 [
make "x (:x / 2)
make "y (:y / 2)
setpencolor "green
]
if :vertex = 1 [
make "x (:width / 2 + ((:width / 2 - :x) / 2))
make "y (:height - ((:height - :y) / 2))
setpencolor "red
]
if :vertex = 2 [
make "x (:width - ((:width - :x) / 2))
make "y (:y / 2)
setpencolor "blue
]
penup
setxy (:x - :width / 2) (:y - :height / 2)
pendown
forward 1
]
hideturtle
end
Lua
Needs LÖVE 2d Engine
math.randomseed( os.time() ) colors, orig = { { 255, 0, 0 }, { 0, 255, 0 }, { 0, 0, 255 } }, {} function love.load() wid, hei = love.graphics.getWidth(), love.graphics.getHeight() orig[1] = { wid / 2, 3 } orig[2] = { 3, hei - 3 } orig[3] = { wid - 3, hei - 3 } local w, h = math.random( 10, 40 ), math.random( 10, 40 ) if math.random() < .5 then w = -w end if math.random() < .5 then h = -h end orig[4] = { wid / 2 + w, hei / 2 + h } canvas = love.graphics.newCanvas( wid, hei ) love.graphics.setCanvas( canvas ); love.graphics.clear() love.graphics.setColor( 255, 255, 255 ) love.graphics.points( orig ) love.graphics.setCanvas() end function love.draw() local iter = 100 --> make this number bigger to speed up rendering for rp = 1, iter do local r, pts = math.random( 6 ), {} if r == 1 or r == 4 then pt = 1 elseif r == 2 or r == 5 then pt = 2 else pt = 3 end local x, y = ( orig[4][1] + orig[pt][1] ) / 2, ( orig[4][2] + orig[pt][2] ) / 2 orig[4][1] = x; orig[4][2] = y pts[1] = { x, y, colors[pt][1], colors[pt][2], colors[pt][3], 255 } love.graphics.setCanvas( canvas ) love.graphics.points( pts ) end love.graphics.setCanvas() love.graphics.draw( canvas ) end
Mathematica
points = 5000;
a = {0, 0};
b = {1, 0};
c = {0.5, 1};
d = {.7, .3};
S = {};
For[i = 1, i < points, i++, t = RandomInteger[2];
If[t == 0, d = Mean[{a, d}],
If[t == 1, d = Mean[{b, d}], d = Mean[{c, d}]]]; AppendTo[S, d]]
Graphics[Point[S]]
Maple
chaosGame := proc(numPoints)
local points, i;
randomize();
use geometry in
RegularPolygon(triSideways, 3, point(cent, [0, 0]), 1);
rotation(tri, triSideways, Pi/2, counterclockwise);
randpoint(currentP, -1/2*sqrt(3)..1/2*sqrt(3), -1/2..1/2);
points := [coordinates(currentP)];
for i to numPoints do
midpoint(mid, currentP, parse(cat("rotate_triSideways_", rand(1..3)(), "_tri")));
points := [op(points), coordinates(mid)];
point(currentP, coordinates(mid));
end do:
end use;
use plottools in
plots:-display( seq([plots:-display([seq(point(points[i]), i = 1..j)])], j = 1..numelems(points) ), insequence=true);
end use;
end proc:
Nim
{{libheader|rapid}}
import random import rapid/gfx var window = initRWindow() .title("Rosetta Code - Chaos Game") .open() surface = window.openGfx() sierpinski = window.newRCanvas() points: array[3, Vec2[float]] for i in 0..<3: points[i] = vec2(cos(PI * 2 / 3 * i.float), sin(PI * 2 / 3 * i.float)) * 300 var point = vec2(rand(0.0..surface.width), rand(0.0..surface.height)) surface.vsync = false surface.loop: draw ctx, step: let vertex = sample(points) point = (point + vertex) / 2 ctx.renderTo(sierpinski): ctx.transform(): ctx.translate(surface.width / 2, surface.height / 2) ctx.rotate(-PI / 2) ctx.begin() ctx.point((point.x, point.y)) ctx.draw(prPoints) ctx.clear(gray(0)) ctx.begin() ctx.texture = sierpinski ctx.rect(0, 0, surface.width, surface.height) ctx.draw() ctx.noTexture() update step: discard
PARI/GP
Note: Find plotmat() here on RosettaCode Wiki. {{Works with|PARI/GP|2.9.1 and above}} [[File:SierpTri1.png|right|thumb|Output SierpTri1.png]]
\\ Chaos Game (Sierpinski triangle) 2/15/17 aev
pChaosGameS3(size,lim)={
my(sz1=size\2,sz2=sz1*sqrt(3),M=matrix(size,size),x,y,xf,yf,v);
x=random(size); y=random(sz2);
for(i=1,lim, v=random(3);
if(v==0, x/=2; y/=2;);
if(v==1, x=sz1+(sz1-x)/2; y=sz2-(sz2-y)/2;);
if(v==2, x=size-(size-x)/2; y/=2;);
xf=floor(x); yf=floor(y); if(xf<1||xf>size||yf<1||yf>size, next);
M[xf,yf]=1;
);\\fend
plotmat(M);
}
\\ Test:
pChaosGameS3(600,30000); \\ SierpTri1.png
{{Output}}
> pChaosGameS3(600,30000); \\ SierpTri1.png
*** matrix(600x600) 18696 DOTS
time = 751 ms.
Pascal
program ChaosGame; // FPC 3.0.2 uses Graph, windows, math; // Return a point on a circle defined by angle and the circles radius // Angle 0 = Radius points to the left // Angle 90 = Radius points upwards Function PointOfCircle(Angle: SmallInt; Radius: integer): TPoint; var Ia: Double; begin Ia:=DegToRad(-Angle); result.x:=round(cos(Ia)*Radius); result.y:=round(sin(Ia)*Radius); end; { Main } var GraphDev,GraphMode: smallint; Triangle: array[0..2] of Tpoint; // Corners of the triangle TriPnt: Byte; // Point in ^^^^ Origin: TPoint; // Defines center of triangle Itterations: integer; // Number of Itterations Radius: Integer; View: viewPorttype; CurPnt: TPoint; Rect: TRect; Counter: integer; begin Repeat {forever} // Get the Itteration count 0=exit Write('Itterations: '); ReadLn(Itterations); if Itterations=0 then halt; // Set Up Graphics screen (everythings Auto detect) GraphDev:=Detect; GraphMode:=0; InitGraph(GraphDev,GraphMode,''); if GraphResult<>grok then begin Writeln('Graphics doesn''t work'); Halt; end; // set Origin to center of the _Triangle_ (Not the creen) GetViewSettings(View); Rect.Create(View.x1,View.y1+10,View.x2,View.y2-10); Origin:=Rect.CenterPoint; Origin.Offset(0,Rect.Height div 6); // Center Triangle on screen // Define Equilateral triangle, Radius:=Origin.y; // Radius of Circumscribed circle for Counter:=0 to 2 do Triangle[Counter]:=PointOfCircle((Counter*120)+90,Radius)+Origin; // Choose random starting point, in the incsribed circle of the triangle Radius:=Radius div 2; // Radius of inscribed circle CurPnt:=PointOfCircle(random(360),random(Radius div 2))+Origin; // Play the Chaos Game for Counter:=0 to Itterations do begin TriPnt:=Random(3); // Select Triangle Point Rect.Create(Triangle[TriPnt],CurPnt);; // Def. rect. between TriPnt and CurPnt CurPnt:=Rect.CenterPoint; // New CurPnt is center of rectangle putPixel(CurPnt.x,CurPnt.y,cyan); // Plot the new CurPnt end; until False; end.
Perl
use Imager; my $width = 1000; my $height = 1000; my @points = ( [ $width/2, 0], [ 0, $height-1], [$height-1, $height-1], ); my $img = Imager->new( xsize => $width, ysize => $height, channels => 3, ); my $color = Imager::Color->new('#ff0000'); my $r = [int(rand($width)), int(rand($height))]; foreach my $i (1 .. 100000) { my $p = $points[rand @points]; my $h = [ int(($p->[0] + $r->[0]) / 2), int(($p->[1] + $r->[1]) / 2), ]; $img->setpixel( x => $h->[0], y => $h->[1], color => $color, ); $r = $h; } $img->write(file => 'chaos_game_triangle.png');
Perl 6
{{works with|Rakudo|2018.10}}
use Image::PNG::Portable;
my ($w, $h) = (640, 640);
my $png = Image::PNG::Portable.new: :width($w), :height($h);
my @vertex = [0, 0], [$w, 0], [$w/2, $h];
my @xy = [0,0], [0,0], [0,0], [0,0];
# :degree must be equal to or less than @xy elements.
(^1e5).race(:4degree).map: {
my $p = ++$ % +@xy;
@xy[$p] = do given @vertex.pick -> @v { ((@xy[$p] »+« @v) »/» 2)».Int };
$png.set: |@xy[$p], 0, 255, 0;
}
$png.write: 'Chaos-game-perl6.png';
Phix
Implements five of the fractals on the wikipedia page. {{libheader|pGUI}}
--
-- demo\rosetta\Chaos_game.exw
--
include pGUI.e
Ihandle dlg, canvas
cdCanvas cddbuffer, cdcanvas
enum TRI,SQ1,SQ2,SQ3,PENT
sequence descs = {"Sierpinsky Triangle",
"Square 1",
"Square 2",
"Square 3",
"Pentagon"}
integer mode = TRI
function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
atom {w,h} = IupGetIntInt(canvas, "DRAWSIZE")
atom {x,y} = {w*0.05,h*0.05}
{w,h} = {w*0.9,h*0.9}
sequence points = iff(mode<SQ1?{{x,y},{x+w/2,y+h},{x+w,y}}:
iff(mode<PENT?{{x,y},{x,y+h},{x+w,y+h},{x+w,y}}
:{{x+w/6,y},{x,y+h*2/3},{x+w/2,y+h},{x+w,y+h*2/3},{x+w*5/6,y}}))
cdCanvasActivate(cddbuffer)
integer last = 0
for i=1 to 1000 do
integer r = rand(length(points))
if mode=TRI or r!=last then
atom {nx,ny} = points[r]
{x,y} = {(x+nx)/2,(y+ny)/2}
cdCanvasPixel(cddbuffer, x, y, CD_GREY)
if mode=SQ2
or mode=SQ3 then
r = mod(r,length(points))+1
if mode=SQ3 then
r = mod(r,length(points))+1
end if
end if
last = r
end if
end for
cdCanvasFlush(cddbuffer)
IupSetStrAttribute(dlg, "TITLE", "Chaos Game (%s)", {descs[mode]})
return IUP_DEFAULT
end function
function timer_cb(Ihandle /*ih*/)
IupUpdate(canvas)
return IUP_IGNORE
end function
function map_cb(Ihandle ih)
cdcanvas = cdCreateCanvas(CD_IUP, ih)
cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
cdCanvasSetBackground(cddbuffer, CD_WHITE)
cdCanvasSetForeground(cddbuffer, CD_GRAY)
return IUP_DEFAULT
end function
function esc_close(Ihandle /*ih*/, atom c)
if c=K_ESC then return IUP_CLOSE end if
if c=' ' then
mode += 1
if mode>PENT then
mode = TRI
end if
cdCanvasClear(cddbuffer)
IupRedraw(canvas)
end if
return IUP_CONTINUE
end function
procedure main()
IupOpen()
canvas = IupCanvas(NULL)
IupSetAttribute(canvas, "RASTERSIZE", "640x640")
IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))
IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))
dlg = IupDialog(canvas)
IupSetAttribute(dlg, "TITLE", "Chaos Game")
IupSetCallback(dlg, "K_ANY", Icallback("esc_close"))
IupShow(dlg)
IupSetAttribute(canvas, "RASTERSIZE", NULL)
Ihandle timer = IupTimer(Icallback("timer_cb"), 40)
IupMainLoop()
IupClose()
end procedure
main()
Processing
size(300, 260); background(#ffffff); // white int x = floor(random(width)); int y = floor(random(height)); int colour = #ffffff; for (int i=0; i<30000; i++) { int v = floor(random(3)); switch (v) { case 0: x = x / 2; y = y / 2; colour = #00ff00; // green break; case 1: x = width/2 + (width/2 - x)/2; y = height - (height - y)/2; colour = #ff0000; // red break; case 2: x = width - (width - x)/2; y = y / 2; colour = #0000ff; // blue } set(x, height-y, colour); }
Python
import argparse import random import shapely.geometry as geometry import numpy as np import matplotlib.pyplot as plt import matplotlib.animation as animation def main(args): # Styles plt.style.use("ggplot") # Creating figure fig = plt.figure() line, = plt.plot([], [], ".") # Limit axes plt.xlim(0, 1) plt.ylim(0, 1) # Titles title = "Chaos Game" plt.title(title) fig.canvas.set_window_title(title) # Getting data data = get_data(args.frames) # Creating animation line_ani = animation.FuncAnimation( fig=fig, func=update_line, frames=args.frames, fargs=(data, line), interval=args.interval, repeat=False ) # To save the animation install ffmpeg and uncomment # line_ani.save("chaos_game.gif") plt.show() def get_data(n): """ Get data to plot """ leg = 1 triangle = get_triangle(leg) cur_point = gen_point_within_poly(triangle) data = [] for _ in range(n): data.append((cur_point.x, cur_point.y)) cur_point = next_point(triangle, cur_point) return data def get_triangle(n): """ Create right triangle """ ax = ay = 0.0 a = ax, ay bx = 0.5 * n by = 0.75 * (n ** 2) b = bx, by cx = n cy = 0.0 c = cx, cy triangle = geometry.Polygon([a, b, c]) return triangle def gen_point_within_poly(poly): """ Generate random point inside given polygon """ minx, miny, maxx, maxy = poly.bounds while True: x = random.uniform(minx, maxx) y = random.uniform(miny, maxy) point = geometry.Point(x, y) if point.within(poly): return point def next_point(poly, point): """ Generate next point according to chaos game rules """ vertices = poly.boundary.coords[:-1] # Last point is the same as the first one random_vertex = geometry.Point(random.choice(vertices)) line = geometry.linestring.LineString([point, random_vertex]) return line.centroid def update_line(num, data, line): """ Update line with new points """ new_data = zip(*data[:num]) or [(), ()] line.set_data(new_data) return line, if __name__ == "__main__": arg_parser = argparse.ArgumentParser(description="Chaos Game by Suenweek (c) 2017") arg_parser.add_argument("-f", dest="frames", type=int, default=1000) arg_parser.add_argument("-i", dest="interval", type=int, default=10) main(arg_parser.parse_args())
R
Note: Find plotmat() here on RosettaCode Wiki. {{trans|PARI/GP}} {{Works with|R|3.3.1 and above}} [[File:SierpTriR1.png|right|thumb|Output SierpTriR1.png]]
# Chaos Game (Sierpinski triangle) 2/15/17 aev # pChaosGameS3(size, lim, clr, fn, ttl) # Where: size - defines matrix and picture size; lim - limit of the dots; # fn - file name (.ext will be added); ttl - plot title; pChaosGameS3 <- function(size, lim, clr, fn, ttl) { cat(" *** START:", date(), "size=",size, "lim=",lim, "clr=",clr, "\n"); sz1=floor(size/2); sz2=floor(sz1*sqrt(3)); xf=yf=v=0; M <- matrix(c(0), ncol=size, nrow=size, byrow=TRUE); x <- sample(1:size, 1, replace=FALSE); y <- sample(1:sz2, 1, replace=FALSE); pf=paste0(fn, ".png"); for (i in 1:lim) { v <- sample(0:3, 1, replace=FALSE); if(v==0) {x=x/2; y=y/2;} if(v==1) {x=sz1+(sz1-x)/2; y=sz2-(sz2-y)/2;} if(v==2) {x=size-(size-x)/2; y=y/2;} xf=floor(x); yf=floor(y); if(xf<1||xf>size||yf<1||yf>size) {next}; M[xf,yf]=1; } plotmat(M, fn, clr, ttl, 0, size); cat(" *** END:",date(),"\n"); } pChaosGameS3(600, 30000, "red", "SierpTriR1", "Sierpinski triangle")
{{Output}}
> pChaosGameS3(600, 30000, "red", "SierpTriR1", "Sierpinski triangle")
*** START: Wed Feb 15 21:40:48 2017 size= 600 lim= 30000 clr= red
*** Matrix( 600 x 600 ) 15442 DOTS
*** END: Wed Feb 15 21:40:51 2017
Racket
{{trans|Haskell}}
#lang racket
(require 2htdp/image)
(define SIZE 300)
(define (game-of-chaos fns WIDTH HEIGHT SIZE
#:offset-x [offset-x 0] #:offset-y [offset-y 0]
#:iters [iters 10000]
#:bg [bg 'white] #:fg [fg 'black])
(define dot (square 1 'solid fg))
(define all-choices (apply + (map first fns)))
(for/fold ([image (empty-scene WIDTH HEIGHT bg)]
[x (random)] [y (random)]
#:result image)
([i (in-range iters)])
(define picked (random all-choices))
(define fn (for/fold ([acc 0] [result #f] #:result result) ([fn (in-list fns)])
#:break (> acc picked)
(values (+ (first fn) acc) (second fn))))
(match-define (list x* y*) (fn x y))
(values (place-image dot (+ offset-x (* SIZE x*)) (+ offset-y (* SIZE y*)) image)
x* y*)))
(define (draw-triangle)
(define ((mid a b) x y) (list (/ (+ a x) 2) (/ (+ b y) 2)))
(define (triangle-height x) (* (sqrt 3) 0.5 x))
(game-of-chaos (list (list 1 (mid 0 0))
(list 1 (mid 1 0))
(list 1 (mid 0.5 (triangle-height 1))))
SIZE (triangle-height SIZE) SIZE))
(define (draw-fern)
(define (f1 x y) (list 0 (* 0.16 y)))
(define (f2 x y) (list (+ (* 0.85 x) (* 0.04 y)) (+ (* -0.04 x) (* 0.85 y) 1.6)))
(define (f3 x y) (list (+ (* 0.2 x) (* -0.26 y)) (+ (* 0.23 x) (* 0.22 y) 1.6)))
(define (f4 x y) (list (+ (* -0.15 x) (* 0.28 y)) (+ (* 0.26 x) (* 0.24 y) 0.44)))
(game-of-chaos (list (list 1 f1) (list 85 f2) (list 7 f3) (list 7 f4))
(/ SIZE 2) SIZE (/ SIZE 11) #:offset-x 70 #:offset-y 10
#:bg 'black #:fg 'white))
(define (draw-dragon)
(game-of-chaos
(list (list 1 (λ (x y) (list (+ (* 0.5 x) (* -0.5 y)) (+ (* 0.5 x) (* 0.5 y)))))
(list 1 (λ (x y) (list (+ (* -0.5 x) (* 0.5 y) 1) (+ (* -0.5 x) (* -0.5 y))))))
SIZE (* 0.8 SIZE) (/ SIZE 1.8) #:offset-x 64 #:offset-y 120))
(draw-triangle)
(draw-fern)
(draw-dragon)
REXX
/*REXX pgm draws a Sierpinski triangle by running the chaos game with a million points*/
parse value scrsize() with sd sw . /*obtain the depth and width of screen.*/
sw= sw - 2 /*adjust the screen width down by two. */
sd= sd - 4 /* " " " depth " " four.*/
parse arg pts chr seed . /*obtain optional arguments from the CL*/
if pts=='' | pts=="," then pts= 1000000 /*Not specified? Then use the default.*/
if chr=='' | chr=="," then chr= '∙' /* " " " " " " */
if datatype(seed,'W') then call random ,,seed /*Is specified? " " RANDOM seed.*/
x= sw; hx= x % 2; y= sd /*define the initial starting position.*/
@.= ' ' /* " all screen points as a blank. */
do pts; ?= random(1, 3) /* [↓] draw a # of (million?) points.*/
select /*?: will be a random number: 1 ──► 3.*/
when ?==1 then parse value x%2 y%2 with x y
when ?==2 then parse value hx+(hx-x)%2 sd-(sd-y)%2 with x y
otherwise parse value sw-(sw-x)%2 y%2 with x y
end /*select*/
@.x.y= chr /*set the X, Y point to a bullet.*/
end /*pts*/ /* [↑] one million points ≡ overkill? */
/* [↓] display the points to the term.*/
do row=sd to 0 by -1; _= /*display the points, one row at a time*/
do col=0 for sw+2 /* " a row (one line) of image. */
_= _ || @.col.row /*construct a " " " " " */
end /*col*/ /*Note: display image from top──►bottom*/
/* [↑] strip trailing blanks (output).*/
say strip(_, 'T') /*display one row (line) of the image. */
end /*row*/ /*stick a fork in it, we're all done. */
This REXX program makes use of '''SCRSIZE''' REXX program (or BIF) which is used to determine the screen
width and depth of the terminal (console). Some REXXes don't have this BIF.
The '''SCRSIZE.REX''' REXX program is included here ───► [[SCRSIZE.REX]].
(Shown at '''1/10 size on a 426×201 screen.)
'''output''' when using the following input: , █
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```
## Ring
```ring
# Project : Chaos game
load "guilib.ring"
paint = null
new qapp
{
win1 = new qwidget() {
setwindowtitle("Archimedean spiral")
setgeometry(100,100,500,600)
label1 = new qlabel(win1) {
setgeometry(10,10,400,400)
settext("")
}
new qpushbutton(win1) {
setgeometry(150,500,100,30)
settext("draw")
setclickevent("draw()")
}
show()
}
exec()
}
func draw
p1 = new qpicture()
color = new qcolor() {
setrgb(0,0,255,255)
}
pen = new qpen() {
setcolor(color)
setwidth(1)
}
paint = new qpainter() {
begin(p1)
setpen(pen)
x = floor(random(10)/10 * 200)
y = floor(random(10/10) * 173)
for i = 1 to 20000
v = floor(random(10)/10 * 3) + 1
if v = 1
x = x/2
y = y/2
ok
if v = 2
x = 100 + (100-x)/2
y = 173 - (173-y)/2
ok
if v = 3
x = 200 - (200-x)/2
y = y/2
ok
drawpoint(x,y)
next
endpaint()
}
label1 {setpicture(p1) show()}
```
* [https://lh3.googleusercontent.com/-xqBO5MB8fpc/Wg05SvwaF9I/AAAAAAAABDA/UGI2goKdDoAR6nbbGZF0YcuwGG6tancvACLcBGAs/s1600/CalmoSoftChaos.jpg Chaos Game (image)]
## Run BASIC
```runbasic
x = int(rnd(0) * 200)
y = int(rnd(0) * 173)
graphic #g, 200,200
#g color("green")
for i =1 TO 20000
v = int(rnd(0) * 3) + 1
if v = 1 then
x = x/2
y = y/2
end if
if v = 2 then
x = 100 + (100-x)/2
y = 173 - (173-y)/2
end if
if v = 3 then
x = 200 - (200-x)/2
y = y/2
end if
#g set(x,y)
next
render #g
```
## Rust
Dependencies: image, rand
```rust
extern crate image;
extern crate rand;
use std::fs::File;
use rand::Rng;
use std::f32;
fn main() {
let max_iterations = 50_000u32;
let img_side = 800u32;
let tri_size = 400f32;
// Create a new ImgBuf
let mut imgbuf = image::ImageBuffer::new(img_side, img_side);
// Create triangle vertices
let mut vertices: [[f32; 2]; 3] = [[0f32, 0f32]; 3];
for i in 0..vertices.len() {
vertices[i][0] =
(img_side as f32 / 2.) + (tri_size / 2.) * (f32::consts::PI * i as f32 * 2. / 3.).cos();
vertices[i][1] =
(img_side as f32 / 2.) + (tri_size / 2.) * (f32::consts::PI * i as f32 * 2. / 3.).sin();
}
for v in &vertices {
imgbuf.put_pixel(v[0] as u32, v[1] as u32, image::Luma([255u8]));
}
// Iterate chaos game
let mut rng = rand::weak_rng();
let mut x = img_side as f32 / 2.;
let mut y = img_side as f32 / 2.;
for _ in 0..max_iterations {
let choice = rng.gen_range(0, vertices.len());
x = (x + vertices[choice][0]) / 2.;
y = (y + vertices[choice][1]) / 2.;
imgbuf.put_pixel(x as u32, y as u32, image::Luma([255u8]));
}
// Save image
let fout = &mut File::create("fractal.png").unwrap();
image::ImageLuma8(imgbuf).save(fout, image::PNG).unwrap();
}
```
## Scala
### Java Swing Interoperability
```Scala
import javax.swing._
import java.awt._
import java.awt.event.ActionEvent
import scala.collection.mutable
import scala.util.Random
object ChaosGame extends App {
SwingUtilities.invokeLater(() =>
new JFrame("Chaos Game") {
class ChaosGame extends JPanel {
private val (dim, margin)= (new Dimension(640, 640), 60)
private val sizez: Int = dim.width - 2 * margin
private val (stack, r) = (new mutable.Stack[ColoredPoint], new Random)
private val points = Seq(new Point(dim.width / 2, margin),
new Point(margin, sizez),
new Point(margin + sizez, sizez)
)
private val colors = Seq(Color.red, Color.green, Color.blue)
override def paintComponent(gg: Graphics): Unit = {
val g = gg.asInstanceOf[Graphics2D]
def drawPoints(g: Graphics2D): Unit = {
for (p <- stack) {
g.setColor(colors(p.colorIndex))
g.fillOval(p.x, p.y, 1, 1)
}
}
super.paintComponent(gg)
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)
drawPoints(g)
}
private def addPoint(): Unit = {
val colorIndex = r.nextInt(3)
def halfwayPoint(a: Point, b: Point, idx: Int) =
new ColoredPoint((a.x + b.x) / 2, (a.y + b.y) / 2, idx)
stack.push(halfwayPoint(stack.top, points(colorIndex), colorIndex))
}
class ColoredPoint(x: Int, y: Int, val colorIndex: Int) extends Point(x, y)
stack.push(new ColoredPoint(-1, -1, 0))
new Timer(100, (_: ActionEvent) => {
if (stack.size < 50000) {
for (i <- 0 until 1000) addPoint()
repaint()
}
}).start()
setBackground(Color.white)
setPreferredSize(dim)
}
add(new ChaosGame, BorderLayout.CENTER)
pack()
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
setLocationRelativeTo(null)
setResizable(false)
setVisible(true)
}
)
}
```
## Scilab
This script uses complex numbers to represent (x,y) coordinates: real part as x position, and imaginary part as y position.
//Input
n_sides = 3;
side_length = 1;
ratio = 0.5;
n_steps = 1.0d5;
first_step = 0;
if n_sides<3 then
error("n_sides should be at least 3.");
end
//Calculating vertices' positions
theta = (2 * %pi) / n_sides;
alpha = (180 - (360/n_sides)) / 2 * (%pi/180);
radius = (sin(theta) / side_length) / sin(alpha);
vertices = zeros(1,n_sides);
for i=1:n_sides
vertices(i) = radius * exp( %i * theta * (i-1) ); //equally spaced vertices over a circumference
//centered on 0 + 0i, or (0,0)
end
clear theta alpha radius i
//Iterations
tic();
points = zeros(1,n_steps);
points(1) = first_step;
i = 2;
while i <= n_steps
random=grand(1,'prm',[1:n_sides]'); //sort vertices randomly
random=random(1); //choose the first random vertices
points(i) = ( vertices(random) - points(i-1) ) * (1-ratio) + points(i-1);
i = i + 1;
end
time=toc();
disp('Time: '+string(time)+'s.');
//Ploting
scf(0); clf();
xname('Chaos game: '+string(n_sides)+'-sides polygon');
plot2d(real(points),imag(points),0)
plot2d(real(vertices),imag(vertices),-3);
set(gca(),'isoview','on');
```
{{out}}
It outputs a graphic window and prints on the console the time elapsed during iterations.
```txt
Time: 1.0424433s.
```
## Sidef
```ruby
require('Imager')
var width = 600
var height = 600
var points = [
[width//2, 0],
[ 0, height-1],
[height-1, height-1],
]
var img = %O|Imager|.new(
xsize => width,
ysize => height,
)
var color = %O|Imager::Color|.new('#ff0000')
var r = [(width-1).irand, (height-1).irand]
30000.times {
var p = points.rand
r[] = (
(p[0] + r[0]) // 2,
(p[1] + r[1]) // 2,
)
img.setpixel(
x => r[0],
y => r[1],
color => color,
)
}
img.write(file => 'chaos_game.png')
```
Output image: [https://github.com/trizen/rc/blob/master/img/chaos-game-sidef.png Chaos game]
## Simula
```simula
BEGIN
INTEGER U, COLUMNS, LINES;
COLUMNS := 40;
LINES := 80;
U := ININT;
BEGIN
CHARACTER ARRAY SCREEN(0:LINES, 0:COLUMNS);
INTEGER X, Y, I, VERTEX;
FOR X := 0 STEP 1 UNTIL LINES-1 DO
FOR Y := 0 STEP 1 UNTIL COLUMNS-1 DO
SCREEN(X, Y) := ' ';
X := RANDINT(0, LINES - 1, U);
Y := RANDINT(0, COLUMNS - 1, U);
FOR I := 1 STEP 1 UNTIL 5000 DO
BEGIN
VERTEX := RANDINT(1, 3, U);
IF VERTEX = 1 THEN BEGIN X := X // 2;
Y := Y // 2;
END ELSE
IF VERTEX = 2 THEN BEGIN X := LINES // 2 + (LINES // 2 - X) // 2;
Y := COLUMNS - (COLUMNS - Y) // 2;
END ELSE
IF VERTEX = 3 THEN BEGIN X := LINES - (LINES - X) // 2;
Y := Y // 2;
END ELSE ERROR("VERTEX OUT OF BOUNDS");
SCREEN(X, Y) := 'X';
END;
FOR Y := 0 STEP 1 UNTIL COLUMNS-1 DO
BEGIN
FOR X := 0 STEP 1 UNTIL LINES-1 DO
OUTCHAR(SCREEN(X, Y));
OUTIMAGE;
END;
END;
END
```
{{in}}
```txt
678
```
{{out}}
```txt
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXX XXX XXXX XXXX XXX XXXX XXX XXXX XXX XXXX XXXX XXX XXX XXX XXXX XXXX
XXXXXXX XXXXXX XXXXXXX XXXXXX XXXXXXX XXXXXXX XXXXXXX XXXXXXX
XXXX XXXXX XXXXX XXXXX XXXXX XXXXX XXXXX XXXX
XX XXX XX XXX XXX XXX XXX XX
XXXXXXXXXXX XXXXXXXXXXX XXXXXXXXXXX XXXXXXXXXX
XXXX XXX XXXX XXXX XXXX XXXX XXX XXXX
XXXXXX XXXXXXX XXXXXXX XXXXXXX
XXXXX XX XX XXXXX XXXXX
XXX XXX XXX XX
XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX
XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX
XXXXXXX XXXXXXX XXXX XX XX XXXX
XXXXX XXXXX XXXXX XXXXX
XXX XXXX XXX XXX
XXXXXXXXXXX XXXXXXXXXXX
XXXX XXXX XXXXXXXXX
XXXXX XX XXXXXXX
XXXXX XXXX
XXX XXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX
XX XX XXX XXX XX XXX XXX XX
XXXXX XXXXX XXXXX XXXXXX
XXXX XXX XXX XXX
XXXXXXXXXXXX XXXXXXXXXXX
XXXXXXXXX XXXX XXXX
XXX XX XXX XX
XXXXX XXXXXX
XXX XXXX
XXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXX
XXX XXX XXX XXX
XXXXXX XXXXXX
XXXX XXXX
X XXXXXXXX XX
XXXXXXXXX
XXX XXX
XXXXX
XXX
```
## Yabasic
```Yabasic
width = 640 : height = 480
open window width, height
window origin "lb"
x = ran(width)
y = ran(height)
for i = 1 to 200000
vertex = int(ran(3))
if vertex = 1 then
x = width / 2 + (width / 2 - x) / 2
y = height - (height - y) / 2
elseif vertex = 2 then
x = width - (width - x) / 2
y = y / 2
else
x = x / 2
y = y / 2
end if
color 255 * (vertex = 0), 255 * (vertex = 1), 255 * (vertex = 2)
dot x, y
next
```
## zkl
This is a half assed animated process - a bunch of pixels are drawn every couple of seconds and the pixmap written [to the file system]. So, if you open the output file ("chaosGame.jpg") it will [auto] update and show the progression of the image.
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl
{{trans|Java}}
[[File:ChaosGame.zkl.jpg|240px|thumb|right]]
```zkl
w,h:=640,640;
bitmap:=PPM(w,h,0xFF|FF|FF); // White background
colors:=T(0xFF|00|00,0x00|FF|00,0x00|00|FF); // red,green,blue
margin,size:=60, w - 2*margin;
points:=T(T(w/2, margin), T(margin,size), T(margin + size,size) );
N,done:=Atomic.Int(0),Atomic.Bool(False);
Thread.HeartBeat('wrap(hb){ // a thread
var a=List(-1,-1);
if(N.inc()<50){
do(500){
colorIndex:=(0).random(3); // (0..2)
b,p:=points[colorIndex], halfwayPoint(a,b);
x,y:=p;
bitmap[x,y]=colors[colorIndex];
a=p;
}
bitmap.writeJPGFile("chaosGame.jpg",True);
}
else{ hb.cancel(); done.set(); } // stop thread and signal done
},2).go(); // run every 2 seconds, starting now
fcn halfwayPoint([(ax,ay)], [(bx,by)]){ T((ax + bx)/2, (ay + by)/2) }
done.wait(); // don't exit until thread is done
println("Done");
```