Why does the game have black borders?
First, if the borders are in pairs, that is on the left AND the right and/or the top AND the bottom, especially if they are equal size, you do not have a problem and cannot and should not try to correct it. These games are designed this way, on a television you might not see it because of something called overscan (advanced users: you may be able to extend the viewable area by using the external geometry pipeline, however this often causes artifacts because you are seeing an area you are not meant to see plus there are the usual weaknesses of that pipeline). One unusual solution to this is to “simulate” overscan by adjusting the range on your monitor so the inside of the black border is sitting on your physical screen edge. You will probably want to pick a resolution that you don’t normaly use so this is only used for Project64! This of course only works for fullscreen. We experimented with various methods of stretching the display to fill the area, but all caused too many problems and
