Question

I’m working on a large Monopoly game as a project in school and ran into a pretty big performance issue. Right now I have a paint method that is drawing the entire board everytime it gets called… this is a big problem because the board only needs to be drawn once in the beggining and only whenever someone buys a house or something. The only components I want to be painted a lot are the players because they are the ones that move around the most and need to be painted.

Here is the paint method of my board:

public void paint(Graphics g){
        super.paint(g);
        Graphics2D g2d = (Graphics2D)g;
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        //Draw all the spots
        for(int i = 0; i < spots.length; i++){
            g2d.setColor(Color.white);
            g2d.fill(spots[i].getRect());
            if(spots[i] instanceof Property){
                if(i < 10){
                    g2d.setColor(spots[i].getColor());
                    Rectangle temp = new Rectangle(spots[i].getRect().x,spots[i].getRect().y,spots[i].getRect().width,spots[i].getRect().height/3);
                    g2d.fill(temp);
                    g2d.setColor(Color.black);
                    g2d.drawString(((Property)spots[i]).getName(), spots[i].getRect().x, spots[i].getRect().height);
                }else if(i >= 10 && i < 20){
                    g2d.setColor(spots[i].getColor());
                    Rectangle temp = new Rectangle(spots[i].getRect().x+spots[i].getRect().width-spots[i].getRect().width/3,spots[i].getRect().y,spots[i].getRect().width/3,spots[i].getRect().height);
                    g2d.fill(temp);
                }else if(i >= 20 && i < 30){
                    g2d.setColor(spots[i].getColor());
                    Rectangle temp = new Rectangle(spots[i].getRect().x,spots[i].getRect().y+spots[i].getRect().height-spots[i].getRect().height/3,spots[i].getRect().width,spots[i].getRect().height/3);
                    g2d.fill(temp);
                    g2d.setColor(Color.black);
                    g2d.drawString(((Property)spots[i]).getName(), spots[i].getRect().x, spots[i].getRect().y);
                }else if(i >= 30 && i < 40){
                    g2d.setColor(spots[i].getColor());
                    Rectangle temp = new Rectangle(spots[i].getRect().x,spots[i].getRect().y,spots[i].getRect().width/3,spots[i].getRect().height);
                    g2d.fill(temp);
                }
            }else if(spots[i] instanceof Railroad){
                if(i == 5)
                    g2d.drawImage(imgTrain3, spots[i].getRect().x, spots[i].getRect().y+spots[i].getRect().height/4, null);
                else if(i == 15)
                    g2d.drawImage(imgTrain4, spots[i].getRect().x+spots[i].getRect().width/4, spots[i].getRect().y, null);
                else if(i == 25)
                    g2d.drawImage(imgTrain1, spots[i].getRect().x, spots[i].getRect().y+spots[i].getRect().height/4, null);
                else if(i == 35)
                    g2d.drawImage(imgTrain2, spots[i].getRect().x+spots[i].getRect().width/4, spots[i].getRect().y, null);
            }else if(spots[i] instanceof Chance){
                if(i == 7)
                    g2d.drawImage(imgChance2, spots[i].getRect().x, spots[i].getRect().y, null);
                else if(i == 22)
                    g2d.drawImage(imgChance2, spots[i].getRect().x, spots[i].getRect().y+spots[i].getRect().height/3, null);
                else if(i == 36)
                    g2d.drawImage(imgChance3, spots[i].getRect().x, spots[i].getRect().y, null);
            }else if(spots[i] instanceof Community){
                if(i == 2)
                    g2d.drawImage(imgComm1, spots[i].getRect().x, spots[i].getRect().y+spots[i].getRect().height/3, null);
                else if(i == 17)
                    g2d.drawImage(imgComm2, spots[i].getRect().x, spots[i].getRect().y, null);
                else if(i == 33)
                    g2d.drawImage(imgComm3, spots[i].getRect().x+spots[i].getRect().width/3, spots[i].getRect().y, null);
            }else{
                g2d.setColor(spots[i].getColor());
                g2d.fill(spots[i].getRect());
            }
        }
        //Draw the outline of every spot
        g2d.setColor(Color.black);
        for(Spot index : spots)
            g2d.draw(index.getRect());
        //Draw the outline of the whole board
        g2d.drawRect(newX, newY, boardSize, boardSize);
        //Draw the Players location
        for(Player index : players)
             g2d.drawImage(index.getImage(), index.getLoc().x, index.getLoc().y, null);
    }

Basically a ton of text to represent the board, and this is being done everytime the board repaints. Any advice?

Bonus question: I also just started working on the move animation for the players after they roll (currently just jump to the destination). I created a timer that takes 1 second per roll (ex: if you roll a 5 it takes 5 seconds to move). Only problem is that I don’t really have a good idea for how to show the slow moving of the player piece from the starting location to end. Just need someone to give me a basic idea so I can head in the right direction.

Answer 1

Paint the board to a BufferedImage. In the paint method, draw the image of the board, then draw the pieces over the top.

BTW – when using Swing, don’t paint in top-level containers, instead use a JComponent or JPanel. For the latter two, override paintComponent(Graphics) rather than paint(Graphics).