Brownian tree

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Brownian tree
You are encouraged to solve this task according to the task description, using any language you may know.

Generate and draw a Brownian Tree.

C

Library: FreeImage

<lang c>#include <string.h>

1. include <stdlib.h>
2. include <time.h>
3. include <math.h>
4. include <FreeImage.h>

1. define NUM_PARTICLES 1000
2. define SIZE 800

void draw_brownian_tree(int world[SIZE][SIZE]){

 int px, py; // particle values
 int dx, dy; // offsets
 int hit;
 int i;

 // set the seed
 world[rand() % SIZE][rand() % SIZE] = 1;

 for (i = 0; i < NUM_PARTICLES; i++){
   // set particle's initial position
   px = rand() % SIZE;
   py = rand() % SIZE;

   while (1){
     // randomly choose a direction
     dx = rand() % 3 - 1;
     dy = rand() % 3 - 1;

     if (dx + px < 0 || dx + px >= SIZE || dy + py < 0 || dy + py >= SIZE){
       // plop the particle into some other random location
       px = rand() % SIZE;
       py = rand() % SIZE;
     }else if (world[py + dy][px + dx] != 0){
       // bumped into something
       world[py][px] = 1;
       break;
     }else{
       py += dy;
       px += dx;
     }
   }
 }

}

int main(){

 int world[SIZE][SIZE];
 FIBITMAP * img;
 RGBQUAD rgb;
 int x, y;

 memset(world, 0, sizeof world);
 srand((unsigned)time(NULL));

 draw_brownian_tree(world);

 img = FreeImage_Allocate(SIZE, SIZE, 32, 0, 0, 0);

 for (y = 0; y < SIZE; y++){
   for (x = 0; x < SIZE; x++){
     rgb.rgbRed = rgb.rgbGreen = rgb.rgbBlue = (world[y][x] ? 255 : 0);
     FreeImage_SetPixelColor(img, x, y, &rgb);
   }
 }
 FreeImage_Save(FIF_BMP, img, "brownian_tree.bmp", 0);
 FreeImage_Unload(img);

}</lang>

Ruby

Library: RMagick

<lang ruby>require 'rubygems' require 'RMagick'

NUM_PARTICLES = 1000 SIZE = 800

def draw_brownian_tree world

 # set the seed
 world[rand SIZE][rand SIZE] = 1

 NUM_PARTICLES.times do
   # set particle's position
   px = rand SIZE
   py = rand SIZE

   hit = false
   until hit
     # randomly choose a direction
     dx = rand(3) - 1
     dy = rand(3) - 1

     if dx + px < 0 or dx + px >= SIZE or dy + py < 0 or dy + py >= SIZE
       # plop the particle into some other random location
       px = rand SIZE
       py = rand SIZE
     elsif world[py + dy][px + dx] != 0
       # bumped into something
       hit = true
       puts "hit"
       world[py][px] = 1
     else
       py += dy
       px += dx
     end
   end
 end

end

world = Array.new(SIZE) { Array.new(SIZE, 0) } srand Time.now.to_i

draw_brownian_tree world

img = Magick::Image.new(SIZE, SIZE) do

 self.background_color = "black"

end

draw = Magick::Draw.new draw.fill "white"

world.each_with_index do |row, y|

 row.each_with_index do |colour, x|
   draw.point x, y if colour != 0
 end

end

draw.draw img img.write "brownian_tree.bmp"</lang>