Question

I am writing a game in Java which is based on a grid top down view. I am not very familiar with the JPanel paintComponent() and repaint() methods and I am having trouble creating a fast screen painting function.
Each tile is an object with a Tile.paintTile(g,x,y) to paint the tile at (x,y) on g. I want to find a nice way to paint only specific tiles, however I cannot find out how to do this.
I have a World class with a TileAt(x,y) to get the tile, but every attempt I have made has caused stuttering or thrown errors.
Any help is appreciated!
-Renmusxd

edit: what I tried:
I am not very used to Java graphics yet, I tried overwriting paintComponent and adding paintComponent(g,x,y) but it doesn’t like my not calling repaint. I no longer have the code because I substituted it with a paintAll version. Sorry.

Answer 1

Normally it is easier to just repaint the entire screen every time – this should be fast enough using Swing on most modern machines.

If you really want to do partial updates, then the best approach is probably:

• Create an offscreen BufferedImage, which should be the same size as your game display area (or slightly larger if you want to allow for scrolling)
• Draw your tiles into this offscreen image.
• When you repaint your view (i.e. in the paintComponent method) then just draw the whole bufferedimage onto the screen in one go.