My game engine is drawing a tiled map on a Canvas inside a JFrame. I am using a Bufferstrategy to get smoother rendering and tried to boost the performance at several points inside the program and end up with ca. 120 frames per second to fill a 1920 * 1080 Window with a black color and draw some isometric 512 * 256 tiles on top. When moveing the map around there are small black lines in between the tiles and . I assume that they occur because some tiles have already been moved to the new position, but the image isn´t done yet, when put on the sreen. But I don´t really have a solution to that and I´m also not sure if I´m right.
I should probably metnion that I´m using two threads in my program, one thread calls update and render methods, the other one is currently just getting user input to move the camera position. Also in some lauches everything works smoothly and in others it flickers very bad.
Here is some code of the window creation and rendering:
private final void createWindow(){
frame = new JFrame(title);
frame.setMinimumSize(size);
frame.setMaximumSize(size);
frame.setPreferredSize(size);
display = new Canvas();
display.setMinimumSize(size);
display.setMaximumSize(size);
display.setPreferredSize(size);
image = ImageLoader.boostPerformance(new BufferedImage((int)size.getWidth(), (int)size.getHeight(), BufferedImage.TYPE_INT_RGB));
graphics = (Graphics2D) image.getGraphics();
frame.add(display);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.requestFocusInWindow();
}
public final void renderToScreen(){
BufferStrategy bs = display.getBufferStrategy();
if(bs==null){
display.createBufferStrategy(bufferCount);
return;
}
graphicsToScreen = (Graphics2D) bs.getDrawGraphics();
graphicsToScreen.drawImage(image, 0, 0, display.getWidth(), display.getHeight(), null);
graphicsToScreen.dispose();
bs.show();
}
I use the Graphics2D graphics object in other classes to draw the tiles.
public void render(Graphics2D g) {
g.setColor(Color.black);
g.fillRect(0, 0, getWidth(), getHeight());
tilemap.render(g);
g.setColor(Color.red);
g.drawString(String.valueOf(Main.actualFps), 30, 30);
}
Above is the render method in another class using the graphics object I mentioned. And here you can see the tile map render method:
private final void renderIsometric(Graphics2D g){
for(int x = 0; x < 4; x++){
for(int y = 3; y >= 0; y--){
if(x > tilesX - 1|| y > tilesY - 1)break;
if(x < 0 || y < 0)continue;
if(map[x][y] == null)continue;
g.drawImage(map[x][y].getImage(), (int)orthoToIso(x, y).x - cameraPosX, (int)orthoToIso(x, y).y - cameraPosY, null);
}
}
}
Finally here is the main loop to ensure that the fps counter is working and the value of 120 fps is correct:
while(running){
long now = System.nanoTime();
double ns = 1000000000.0 / preferredUps;
delta += (now - lastTime) / ns;
lastTime = now;
while(delta >= 1){
//call the update method
update();
updates++;
delta--;
}
//call the render method
render();
frames++;
//refresh the actualUps and actualFps once every second
if(System.currentTimeMillis() - timer > 1000){
timer+=1000;
actualUps = updates;
actualFps = frames;
updates = 0;
frames = 0;
}
}
How can I get rid of these tiny lags and flicker problems? And additionally I have been wondering if it would give better results to use OpenGL via LWJGL instead of Java2D?
Thanks for your help!
