Using BufferStrategy But Still Got Flicker

[maxking1234]

Hi,

I am using the game loop in the tutorial basic game, which uses BufferStrategy,  but when I render my world I still get flicker.
If any one could help I would appreciate it. Loop source code:

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public class Planetoids implements Runnable {    public static int xOffs = 0, yOffs = 0;    public final int WIDTH = 800;    public final int HEIGHT = 600;    private PlanetEarth earth;    private JFrame frame;    private Canvas canvas;    private BufferStrategy bufferStrategy;    public Planetoids() {       frame = new JFrame("Planetoids Pre-Alpha 0.0.1");       JPanel panel = (JPanel) frame.getContentPane();       panel.setPreferredSize(new Dimension(WIDTH, HEIGHT));       panel.setLayout(null);       canvas = new Canvas();       canvas.setBounds(0, 0, WIDTH, HEIGHT);       canvas.setIgnoreRepaint(true);       panel.add(canvas);       canvas.addKeyListener(new InputManager());       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       frame.pack();       frame.setResizable(false);       frame.setVisible(true);       frame.setLocationRelativeTo(null);       canvas.createBufferStrategy(2);       bufferStrategy = canvas.getBufferStrategy();       canvas.requestFocus();       init();    }    private void init() {       earth = new PlanetEarth(30,30);       earth.map = PlanetGenerator.loadMap(30, 30);    }    long desiredFPS = 60;    long desiredDeltaLoop = (1000 * 1000 * 1000) / desiredFPS;    boolean running = true;    public void run() {       long beginLoopTime;       long endLoopTime;       long currentUpdateTime = System.nanoTime();       long lastUpdateTime;       long deltaLoop;       while (running) {          beginLoopTime = System.nanoTime();          render();          lastUpdateTime = currentUpdateTime;          currentUpdateTime = System.nanoTime();          update((int) ((currentUpdateTime - lastUpdateTime) / (1000 * 1000)));          endLoopTime = System.nanoTime();          deltaLoop = endLoopTime - beginLoopTime;          if (deltaLoop > desiredDeltaLoop) {             // Do nothing. We are already late.         } else {             try {                Thread.sleep((desiredDeltaLoop - deltaLoop) / (1000 * 1000));             } catch (InterruptedException e) {                // Do nothing            }          }       }    }    private void render() {       Graphics g =  bufferStrategy.getDrawGraphics();       g.clearRect(0, 0, WIDTH, HEIGHT);       render(g);       g.dispose();       bufferStrategy.show();    }    protected void update(int deltaTime) {    }    protected void render(Graphics g) {       earth.render(g);    }    public static void main(String[] args) {       Planetoids ex = new Planetoids();       new Thread(ex).start();    } }

The world render code:

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public void render(Graphics g) {       super.render(g);       int x = 0, y = 0;       for (int i = 0; i < map.length; i++) {          if (x == width) {             x = 0;             y += 1;          }          switch (map[i]) {          case Tile.TILE_EARTH_DIRT:             g.drawImage(Tile.TILE_EARTH_DIRT_IMG, x * 32 + Planetoids.xOffs, y * 32 + Planetoids.yOffs, 32, 32, null);             break;          case Tile.TILE_EARTH_GRASS:             g.drawImage(Tile.TILE_EARTH_GRASS_IMG, x * 32 + Planetoids.xOffs, y * 32 + Planetoids.yOffs, 32, 32, null);             break;          case Tile.TILE_EARTH_STONE:             g.drawImage(Tile.TILE_EARTH_STONE_IMG, x * 32 + Planetoids.xOffs, y * 32 + Planetoids.yOffs, 32, 32, null);             break;          case Tile.TILE_EARTH_SAND:             g.drawImage(Tile.TILE_EARTH_SAND_IMG, x * 32 + Planetoids.xOffs, y * 32 + Planetoids.yOffs, 32, 32, null);             break;          }          x++;       }    }

Max

[ra4king]

I see nothing wrong with the code. What kind of flickering do you see?

[maxking1234]

When I move about, up and left it flickers

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[maxking1234]

Strangely now I only get flicker when moving up?

[ra4king]

What kind of flickering are you talking about? Flickering means that it disappears for a frame or two then reappears. Maybe you mean it stutters, where it doesn't move smoothly?

[ReBirth]

It's unique that you use int for delta. Show us your class code that moving.

[nsigma]

What kind of flickering are you talking about? Flickering means that it disappears for a frame or two then reappears. Maybe you mean it stutters, where it doesn't move smoothly?

Or do you mean that the image isn't VSynced (ie. you're seeing a bit of the current frame and a bit of the previous one)?  BufferStrategy isn't guaranteed to be VSynced so this can result in flicker, depending on the system (which is?).

[maxking1234]

It's unique that you use int for delta. Show us your class code that moving.

This is the movement code

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public void keyPressed(KeyEvent key) {       switch (key.getKeyCode()) {       case KeyEvent.VK_ESCAPE:          System.exit(0);          break;       case KeyEvent.VK_W:          Planetoids.yOffs += Player.moveSpeed;          break;       case KeyEvent.VK_S:          Planetoids.yOffs -= Player.moveSpeed;          break;       case KeyEvent.VK_A:          Planetoids.xOffs += Player.moveSpeed;          break;       case KeyEvent.VK_D:          Planetoids.xOffs -= Player.moveSpeed;          break;       }

[maxking1234]

What kind of flickering are you talking about? Flickering means that it disappears for a frame or two then reappears. Maybe you mean it stutters, where it doesn't move smoothly?

When I move quite often white rectangles appear instead of the tiles.

[ra4king]

Please tell me you load images once in a constructor/init method somewhere and don't reload them every time you render!

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[maxking1234]

I load them statically in a Tile class?

1	private static Image TILE_DIRT_IMG = new ImageIcon("res/grass.png").getImage();

Does this load them every time I call it??

[ra4king]

Oh ok never mind that's fine. Side note: It's best to use javax.imageio.ImageIO by calling its read(URL) method. You get a URL using ClassName.class.getClassLoader().getResource("res/grass.png");

Hmm white rectangles popping randomly or predictably?

Are there any other rendering codes?

[ReBirth]

Looking on your moving code inside KeyAdapter class, I guess you move hardly, one tile per keypress. If you want a smooth one, you should use delta to calculate the movement little by little each frame.

[maxking1234]

Looking on your moving code inside KeyAdapter class, I guess you move hardly, one tile per keypress. If you want a smooth one, you should use delta to calculate the movement little by little each frame.

Like ?

1	Planetoids.xOffs += Player.moveSpeed * delta

[maxking1234]

Thanks, This seems to have stopped the flicker"!

[ReBirth]

Yes inside your entity class, that's normally what we do for continuous movement. If, in your case you want "blocky" move then yours is right. Just I can't imagine if it'll flicking.

[maxking1234]

Yes inside your entity class, that's normally what we do for continuous movement. If, in your case you want "blocky" move then yours is right. Just I can't imagine if it'll flicking.

Well I think it must of been that as it is now perfect

[ra4king]

I still don't understand how blocky movement == flicker

[theagentd]

I still don't understand how blocky movement == flicker

Someone needs to make a FAQ for this. How are we supposed to help people when they can't describe the problem? =S

[ReBirth]

I still don't understand how blocky movement == flicker

Someone needs to make a FAQ for this. How are we supposed to help people when they can't describe the problem? =S

+1, let's see how many threads that asking same problem again and again.

[ra4king]

Yeah I agree, I hate constantly seeing threads that ask the same questions over and over and over again. I feel compelled to write that FAQ right now.......

@Riven, you should create an FAQ page which a certain group people can edit so we can all contribute stuff to it. Then make a big bold banner on the front page

[Riven]

@Riven, you should create an FAQ page which a certain group people can edit so we can all contribute stuff to it. Then make a big bold banner on the front page

Yeah, it's called a wiki, and was a huge failure on JGO. Not going to bother with it anymore.

[ReBirth]

Let's make simpler, like a sticky post.

[ra4king]

It was a huge failure because I wasn't here! *looks up majestically*

But seriously, an FAQ page would drastically reduce the number of repeat noob threads who don't Google properly.

[sproingie]

There is a FAQ post, but I'm not even sure what the FAQ is here.  Interpolated movement?

[Gjallar]

Interpolated movement?

Yeah... that's the first thing I'd google for if I experience flickering 

[theagentd]

Interpolated movement?

Yeah... that's the first thing I'd google for if I experience flickering 

Maybe it's the new "Something's wrong!"?