I am using a tilemap in which I have square tiles.<br>
Knowing that, the size of the screen and the player position(in world coordinates) how I convert between this systems? Is there any formula?

EDIT:<br>
For example:<br><br>
The top left corner is (0,0)
<b>player position in tiles:</b> (ScreenX / 2, ScreenY / 2)<br>
<b>player position in screen:</b> always (0, 0)<br>
<b>grass tile position in tiles:</b> (Gx, Gy)<br><br>

Now the question is: how can I get the screen coordinates for the grass tile?