Question

I’m making a new game that generates a huge grid (lets say 1000×1000). The player starts in the middle and moves around looking for “points”. The player can only see a portion of the larger grid in the window (15×15). Right now I just have a huge array of rectangles each that paint a bufferedimage of a dirt block that I created. Question: Is there a better variable type I should be using to store all these images?

This is what my Dirt class looks like (holds the rect, and the image which is generated at the beginning):

public class Dirt extends Spot{
    private int index;

    public Dirt(int temp){
        index = temp;
    }

    public Image getImageIndex(){return index;}
}

And here is apart of my Board class that draws all the Dirt:

public class Board extends JPanel{
    private final int BLOCK_SIZE;                                   //Holds the size of each block
    private final int SIZE;                                     //Holds the size of the board
    private DirtImages[] imgs_Dirt = new DirtImages[20];    //Holds 20 random dirt images - generated at begtinning

    private Spot[][] spots;

    public Board(int size, int blocksize){
        SIZE = size;
        BLOCK_SIZE = blocksize;
        //Board
        setSize(SIZE,SIZE);
        //Timer Label
        add(JTimerLabel.getInstance());

        //Create 20 random Images of dirt to use for the rest of dirts
        for(int i = 0; i < 20; i++){
            imgs_Dirt[i] = new DirtImages(new Rectangle(0,0,BLOCK_SIZE,BLOCK_SIZE));
            add(imgs_Dirt[i]);
        }

        //Create Dirt
        spots = new Dirt[500][500];
        java.util.Random randomGenerator = new java.util.Random();
        for(int i = 0; i < spots.length; i++){
            for(int j = 0; j < spots.length; j++)
                spots[i][j] = new Dirt(randomGenerator.nextInt(20));
        }
    }

    public void paint(Graphics g){
        super.paint(g);
        Graphics2D g2d = (Graphics2D)g;
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        //Draw Grid #First
        for(int i = 0; i < spots.length; i++){
            for(int j = 0; j < spots.length; j++)
                if(spots[i][j] != null)
                    g2d.drawImage(imgs_Dirt[((Dirt)spots[i][j]).getImageIndex()].getImage(), BLOCK_SIZE*i,BLOCK_SIZE*j,BLOCK_SIZE,BLOCK_SIZE, null);
        }

        Toolkit.getDefaultToolkit().sync();
        g2d.dispose();
        requestFocus();
    }

Just to clarify. I create 20 Dirt images so that the dirt (when painted) don’t look like they’re tiled but are random. So in my array of Dirt, each Dirt points to a random image.

Additional Question: Now that I create my huge grid, how would I make it so the player starts at the center and I draw the surrounding cells. Currently I start at the beggining of the array in the top left corner of my array. Should I create a boolean flag for each dirt of whether or not it should be drawn?

Answer 1

If you have 1,000,000 Dirts and only 20 images, it’s kind of a waste to store an image in each dirt. You can use an index instead. So to draw, instead of drawing

((Dirt)spots[i][j]).getImage()

you would draw

imgsDirt[((Dirt)spots[i][j]).getImageIndex()]

For the updated question:

You seem to be drawing your whole grid(0-1000,0-1000). What you really want is just to paint the 15×15 ‘viweable’ area. So instead of

    //Draw Grid #First
    for(int i = 0; i < spots.length; i++){
        for(int j = 0; j < spots.length; j++)

it would be

    //Draw Grid #First
    for(int i = player.xpos-7; i < player.xpos+7; i++){
        for(int j = player.ypos - 7; j < player.ypos+7; j++)

You would need an appropriate shift in your drawImage method to make sure it still starts drawing at the upper left of your window.