SandLab.java

gistfile1.txt

import java.awt.*;
import java.util.*;
import java.awt.Color;
import java.util.Random;

public class SandLab
{
  public static void main(String[] args)
  {
    SandLab lab = new SandLab(120, 80);
    lab.run();
  }
  
  //add constants for particle types here
  public static final int EMPTY = 0;
  public static final int METAL = 1;
  public static final int SAND = 2;
  public static final int WATER = 3;
  
  //do not add any more fields
  private int[][] grid;
  int rows;
  int cols;
  private SandDisplay display;
  public static final Color GREY = new Color(150,150,150);
  public static final Color BLACK = new Color(0,0,0);
  public static final Color YELLOW = new Color(255,255,0);
  public static final Color BLUE = new Color(0,0,255); 

  public SandLab(int numRows, int numCols)
  {
    String[] names;
    names = new String[4];
    names[EMPTY] = "Empty";
    names[METAL] = "Metal";
    names[SAND] = "Sand";
    names[WATER] = "Water";
    grid = new int[numRows][numCols];
    rows = numRows;
    cols = numCols;
    display = new SandDisplay("Falling Sand", numRows, numCols, names);
  }
  
  //called when the user clicks on a location using the given tool
  private void locationClicked(int row, int col, int tool)
  {
    grid[row][col] = tool;
  }

  //copies each element of grid into the display
  public void updateDisplay()
  { 
    for(int i=0; i < rows; i++){
      for(int j=0; j < cols; j++){
        int particle = grid[i][j];
        if(particle == METAL){
          display.setColor(i,j,GREY);
        } else if(particle == SAND) {
          display.setColor(i,j,YELLOW);
        } else if(particle == WATER){
          display.setColor(i,j,BLUE);
        } else {
          display.setColor(i,j,BLACK);
        }
      }
    }
  }

  //called repeatedly.
  //causes one random particle to maybe do something.
  public void step()
  {
    Random rand = new Random();
    int row = rand.nextInt(rows);
    int col = rand.nextInt(cols);
    if(
      grid[row][col] == SAND &&
      row != rows - 1 &&
      grid[row+1][col] != METAL &&
      grid[row+1][col] != SAND
    ){
      if(grid[row+1][col] == WATER){
        grid[row][col] = WATER;
      } else {
        grid[row][col] = EMPTY;
      }
      grid[row+1][col] = SAND;
    } else if(grid[row][col] == WATER) {
      int direction = rand.nextInt(3);
      if(
        direction == 0 &&
        col != 0 &&
        grid[row][col-1] == EMPTY
      ) {
        grid[row][col] = EMPTY;
        grid[row][col-1] = WATER;
      } else if(
        direction == 1 &&
        col != cols-1 &&
        grid[row][col+1] == EMPTY
      ) {
        grid[row][col] = EMPTY;
        grid[row][col+1] = WATER;
      } else if(
        direction == 2 &&
        row != rows-1 &&
        grid[row+1][col] == EMPTY
      ) {
        grid[row][col] = EMPTY;
        grid[row+1][col] = WATER;
      }
    }
  }
  
  //do not modify
  public void run()
  {
    while (true)
    {
      for (int i = 0; i < display.getSpeed(); i++)
        step();
      updateDisplay();
      display.repaint();
      display.pause(1);  //wait for redrawing and for mouse
      int[] mouseLoc = display.getMouseLocation();
      if (mouseLoc != null)  //test if mouse clicked
        locationClicked(mouseLoc[0], mouseLoc[1], display.getTool());
    }
  }
}