Hello,
i made a scrolling area for a tile background. That area is included in a certain rectangle. I set that rectangle as a clip region, so when the scrolling area is scrolled, only that rectangle is redrawn. But now i wonder how i could draw something around that clip region.
Thanx for help 
I guess my topic is stupid again ???
I don’t get your problem. To paint outside the clip then just set the clip back to what it was.
seems you understood. I tryed what u said :
when i initiate the whole screen, i draw around the future scrolling area (a gradient) then i set the clip area to the scrolling area. But the surrounding area flickers ! It shouldn’t be redrawn :-o !
Dunno wether it’s a good idea to give my code cause it’s not very short :-\
anyway thank you for your help.
If its flickering, then yes it must be getting painted outside the clip. Are you double-buffering with the window you are painitng on? Post the painting code you’re using.
If you are using an accelerated surface as a back buffer, and you want to only repaint dirty areas of the screen - you will have to take into consideration the underlying surface being lost (forcing a complete repaint). Also, if you are using a BufferStrategy with more than 1 back buffer (perhaps page flipping with either 2/3 pages), you can’t feasibly do dirty repaints at all.
Really thanks for your replies !
public void gameLoop()
{
int lastLoopTime = (int) System.currentTimeMillis();
fpsCounter=0;
int lastFps=0;
Graphics2D g = (Graphics2D) strategy.getDrawGraphics();
/////////////////////////////////////THIS IS THE FLICKERING REPAINTING OUTSIDE CLIPREGION////////////////////////////
GradientPaint gradient = new GradientPaint(0, 0, Color.BLUE, screenWidth, screenHeight, Color.RED);
g.setPaint(gradient);
g.fillRect(0,0,screenWidth,screenHeight)
////////////////////////////////////
setFastRendering(g);
while (gameRunning)
{
int delta = (int)(System.currentTimeMillis() - lastLoopTime);
lastLoopTime = (int) System.currentTimeMillis();
fpsCounter++;
g = (Graphics2D) strategy.getDrawGraphics();
g.clipRect(10,80,screenWidth-20,screenHeight-90);
g.setColor(Color.black);
g.fillRect(10,80,screenWidth-20,screenHeight-90);
//TilesEntities moves
//Background
drawBackground(g);
// collisions
//Entities moves
tank.move(delta);
// drawing
Entity entity = (Entity) entities.get(0);
entity.draw(g);
lastFps=hud.displayFps(g,delta,lastFps,fpsCounter);
// remove any entity that has been marked for clear up
g.dispose();
try { Thread.sleep(0); } catch (Exception e) {}
strategy.show();
//
tank.setHorizontalMovement(0);
scrollEntities(g,delta);
}
}
Here is what i double buffer :-o
public Game()
{
// Determine if page flipping is supported
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
gd = ge.getDefaultScreenDevice();
GraphicsConfiguration gc = gd.getDefaultConfiguration();
BufferCapabilities bufCap = gc.getBufferCapabilities();
boolean page = bufCap.isPageFlipping();
Frame container = new Frame(gd.getDefaultConfiguration());
win = new Window(container);
gd.setFullScreenWindow(win);
win.setIgnoreRepaint(true);
container.pack();
container.setResizable(false);
container.setVisible(true);
container.setIgnoreRepaint(true);
container.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
container.addKeyListener(new KeyInputHandler());
win.addMouseListener(new MouseInputHandler());
win.createBufferStrategy(2);
strategy = win.getBufferStrategy();
container.requestFocus();
hud = new HUD();
cursorChanger = new CursorChanger();
cursorChanger.setCursor("default");
iniBackground();
startGame();
gameLoop();
}
As Anon666 said I don’t think its possible to do dirty (partial) repaints with a BufferStrategy (you could with a single-buffer strategy but there’s no point, it would be inefficient, and there would be flicker & artifacts). The reason you can’t do it is the bufferStrategy.show() method paints the complete back image, not a part of it. You can still do partial paints on the back-buffer and then show the whole thing, however. This is what you’re doing already and it may be sufficient. Performance-wise its worse than the below solution but since you’re using full-screen, on Windows you may be able to flip rather than blit the back buffers which is very quick.
If you really want to do partial/clipped paints then you will have to do away with the bufferStrategy and make your own VolatileImage back buffer which you can use to do a clipped drawImage to the screen. This is a bit of work though, so you may want to just continue as you are. I hope that helps,
Keith
:
nice answer !
I will give up this idea and make no clip :-\ . (no time enough to try volatileImage now ::))
Anyway i think it will work not so bad without clipping.
edit : is there an efficient solution to clip images ?
Thanx for replying ! 8)