well it's pretty simple, you need to position a quad or sprite in front of the camera in a way that gives you the same amount of texels and pixels onscreen. If you once got that, you need to move the quad/sprite by a half pixel, because texels are centered, pixels are not.
You should use a texture flag that turns off mipmapping to get a sharp texture, eg. flag 256.
You should use a texture flag that turns off mipmapping to get a sharp texture, eg. flag 256.