Cars on the wrong side of the road

In the next few betas the cars will drive on the left side of the road for the UK and other countries that do that kind of thing. There are actually two sim changes to make this happen:

• The road.net format allows us to specify where on theh road the cars drive, as a ratio from 0 to 1 (0 = all the way to the left, 1 = all the way to the right). So in the US, all car positions are mor than 0.5 but in the UK less than 0.5.
• The library system now allows you to specify that a given file only be used in certain DSFs by painting a bitmap. So Sergio made a black and white PNG file with the right-side countries in black and left-side countries in white. I made a special road.net with the lanes on the left, and the PNG file controls which road.net gets used (the normal one or special left-side one).

I will try to post the spec for using PNG files to control library export in the next few days. This is a very powerful feature because it lets you paint the regions over which objects may be used. This technique will work for roads, objects, facades, or any other type of file used by X-Plane.