Simulation of a universe in processing/Java

import processing.opengl.*;

int aCount = 3;
int dim = 150;
float XYdir = 0;


boolean matter[][][][] = new boolean[aCount][dim+1][dim+1][dim+1];

void setup()  {

  size(displayWidth,displayHeight,OPENGL);
  initUniverse();
}

void draw()  {


  background(0);
  XYdir++;

  camera( dim*3, (dim/2)*5 + (cos(radians(XYdir)) * -dim*8), (dim/2)*5 + (sin(radians(XYdir)) * -dim*8), dim*3, (dim/2)*5, (dim/2)*5, 1, 0, 0);
  drawUniverse();
}

void drawUniverse()  {

  for(int i = 0; i <= dim; i++)  {

    for(int j = 0; j <= dim; j++)  {

      for(int t = 0; t <= dim; t++)  {

        if(matter[0][i][j][t] == true && matter[1][i][j][t] == true)  {

          matter[1][i][j][t] = false;
          matter[0][i][j][t] = false;
          matter[2][i][j][t] = true;
        }else if(matter[1][i][j][t] == true && matter[2][i][j][t] == true)  {

          matter[1][i][j][t] = false;
          matter[2][i][j][t] = false;
          matter[0][i][j][t] = true;
        }else if(matter[0][i][j][t] == true && matter[2][i][j][t] == true)  {

          matter[0][i][j][t] = false;
          matter[2][i][j][t] = false;
          matter[1][i][j][t] = true;
        }

        int pos1 = (int)random(-2,2);
        int pos2 = (int)random(-2,2);
        int pos3 = (int)random(-2,2);

        if(i + pos1 < dim && j + pos2 < dim && t + pos3 < dim)  {

          if(i + pos1 > -1 && j + pos2 > -1 && t + pos3 > -1)  {


              matter[0][i + pos1][j + pos2][t + pos3] = matter[0][i][j][t];

              matter[1][i + pos1][j + pos2][t + pos3] = matter[1][i][j][t];

              matter[2][i + pos1][j + pos2][t + pos3] = matter[2][i][j][t];

          }
        }

        if(matter[0][i][j][t] == true)  {

          fill(255,0,0);

          pushMatrix();
          translate(i*5,j*5,t*5);
          rotateX(radians(45));

          rotateX(radians(45));
          box(5);
          popMatrix();
        }

        if(matter[1][i][j][t] == true)  {

          fill(0,255,0);

          pushMatrix();
          translate(i*5,j*5,t*5);
          rotateX(radians(45));

          rotateX(radians(45));
          box(5);
          popMatrix();
        }

        if(matter[2][i][j][t] == true)  {

          fill(0,0,255);

          pushMatrix();
          translate(i*5,j*5,t*5);
          rotateX(radians(45));

          rotateX(radians(45));
          box(5);
          popMatrix();
        }
      }
    }
  }
}

void initUniverse()  {

  for(int i = 0; i <= dim; i++)  {

    for(int j = 0; j <= dim; j++)  {

      for(int t = 0; t <= dim; t++)  {

        matter[0][i][j][t] = false;
        matter[1][i][j][t] = false;
        matter[2][i][j][t] = false;

        int iii = (int)random( 1000);

        if(iii == 1)  {

          matter[0][i][j][t] = true;
        }

        if(iii == 2)  {

          matter[1][i][j][t] = true;
        }

        if(iii == 3)  {

          matter[2][i][j][t] = true;
        }
      }
    }
  }
}