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Thread: anti doublebuffer or lag?

  1. #1
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    Default anti doublebuffer or lag?

    So far on my demo you can walk around (no collision detection yet) and type a message. When I was walking around I noticed a problem. Every once in a while the character sprite will lag/jump, and im not sure if this is due to the fact that I don't double buffer, or my code is laggy. Here is all of my code.


    gameMain.class
    import javax.swing.JFrame;
     
     
    public class gameMain {
    	public static void main(String[] args){
    		chatBox chatBox = new chatBox();
    		keyBoard kb = new keyBoard();
    		gui gui = new gui();
     
     
    		JFrame f = new JFrame("BrettScape");
    		f.setSize(646,500);
    		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    		f.setResizable(false);
     
    		f.add(gui);
    		f.addKeyListener(kb);
    		f.setFocusTraversalKeysEnabled(false);
    		f.setVisible(true);
     
     
    		while(true) {
    			gui.updateScreen(chatBox.getMessages(), kb.getMessage(), kb.getX(), kb.getY());
    		}
    	}	
    }


    chatBox.class
     
    public  class chatBox {
    	String messageBox[]={"Welcome to BrettScape!","","","",""};
     
    	public String[] getMessages(){
    		return messageBox;
    	}
    	public void addMessage(String newMess){
    		messageBox[4] = messageBox[3];
    		messageBox[3] = messageBox[2];
    		messageBox[2] = messageBox[1];
    		messageBox[1] = messageBox[0];
    		messageBox[0] = newMess;
    	}
    }


    gui.class
    import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.IOException;
     
    import javax.imageio.ImageIO;
    import javax.swing.*;
     
    public class gui extends JPanel {
    	BufferedImage img,chatBoxImg,avatar;
    	String messages[];
    	String typing;
    	int map[][]={ //I know this map is in my gui class, but I'm going to add a different class for maps.
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
    			{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
    	};
    	int messCount,row,column,playerX,playerY;
     
    	public gui(){
    		try {
    			img = ImageIO.read(new File("tiles.png"));
    			chatBoxImg = ImageIO.read(new File("chat.png"));
    			avatar = ImageIO.read(new File("avatar.png"));
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
     
    	public void updateScreen(String[] messages, String typing, int playerX, int playerY){
    		this.messages = messages;
    		this.typing = typing;
    		this.playerX = playerX;
    		this.playerY = playerY;
    		repaint();
    	}
     
    	public void paintComponent(Graphics g){		
    		//draw first tile layer
    		for(column=0;column<=11;column++) {
    			for(row=0;row<=19;row++){
    				g.drawImage(img, row*32, column*32, row*32+32, column*32+32, map[column][row]*32, 0, map[column][row]*32+32, 32, null);
    			}
    		}	
     
    		//second layer
    		g.drawImage(avatar, playerX, playerY, null);
     
    		//third layer
     
    		//draws messages for chat box
    		g.drawImage(chatBoxImg, 0, 384, null);
    		for(messCount=0;messCount<=4;messCount++){
    			g.drawString(messages[messCount], 5, 400+(messCount*14));
    		}	
     
    		//draw what the person is typing
    		g.drawString(typing+"*", 5, 468);
    	}
    }


    keyBoard.class
    import java.awt.event.*;
     
    public class keyBoard implements KeyListener {
    	int keyCode;
    	int playerX,playerY=10;
    	String message="";
     
     
    	public int getX(){
    		return playerX;
    	}
     
    	public int getY(){
    		return playerY;
    	}
     
    	public String getMessage(){
    		return message;
    	}
     
    	public void keyPressed(KeyEvent e){
    		keyCode = e.getKeyCode();
     
    		if (keyCode == KeyEvent.VK_LEFT) {
    			playerX-=5;
    		}
    		if (keyCode == KeyEvent.VK_RIGHT) {
    			playerX+=5;
    		}
    		if (keyCode == KeyEvent.VK_UP) {
    			playerY-=5;
    		}
    		if (keyCode == KeyEvent.VK_DOWN) {
    			playerY+=5;
    		}
    		//Detection of normal keys
    		if ("ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*(),PeriodComma/?;:`~[]{}=+<>Space".indexOf(KeyEvent.getKeyText(keyCode)) >= 0) {
    			message+=KeyEvent.getKeyText(keyCode).replace("Space", " ").replace("Period", ".").replace("Comma", ",").toLowerCase();
     
    			//capitalize the first letter
    			if (message.length() == 1) 
    				message = message.toUpperCase();
    		}
     
    		//if backspace delete last letter
    		if (KeyEvent.getKeyText(keyCode) == "Backspace") {
    			if(message.length() >= 1)
    				message = message.substring(0, message.length()-1);
    		}
     
     
     
     
    	}
     
     
    	public void keyReleased(KeyEvent e){
     
    	}
     
    	public void keyTyped(KeyEvent e){
     
    	}
    }


  2. #2
    Administrator copeg's Avatar
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    Default Re: anti doublebuffer or lag?

    Swing components are by default double buffered, so this might not be the issue. You may wish to profile your code by printing out a bunch of times for certain routines...there are a few areas that can be optimized (for example the tiling could be written once to a BufferedImage, and then rather than loop to draw each tile each time in the paintComponent, you could just draw that the tiling composite image once).

  3. #3
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    Default Re: anti doublebuffer or lag?

    I'm thinking of changing my engine. Instead of my character walking around im going to change it so the map scrolls and the character stays stationary. How would i optimize that?

    EDIT: When I was running my game I noticed that it was making my computer laggy. I opened the task manager and it was using 62%+ of my CPU! Am I calling update too often, should I add a sleep method in my loop? I'm not sure how to make this go down.

    Second EDIT: I had the thread sleep for 16ms and that brought it down to 11%CPU
    Last edited by Brt93yoda; August 19th, 2010 at 08:25 PM.

  4. #4
    Super Moderator helloworld922's Avatar
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    Default Re: anti doublebuffer or lag?

    It's much easier to have a stationary map than a stationary character (at least in the data structure, how you draw it doesn't matter).

    Simply having to move every component of the map would take a very long time compared to moving just the one character.

    What I would recommend is having the camera follow the character around, but still have the character moving through the map.

    A simple optimization for collision detection is to quantify your entire map into a grid, then when your character moves, you only have to check collision against items that are in the same grid as the character rather than having to check collision against everything.

  5. #5
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    Default Re: anti doublebuffer or lag?

    What I would recommend is having the camera follow the character around, but still have the character moving through the map.
    So how would I go about doing that?

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