Road Signs

To make things look more like a real road system, I have begun to implement a road sign system. It's still in it's infancy, but it currently uses road nodes to generate a list of all the roads meeting at that node and create a texture for the sign showing the road names. Te texture is created in a similar way to the sprite font, however this time it copies pixels from a font bitmap into the target bitmap in memory, then binds this to a texture name and so on.

Some work needs doing to remove duplicates and put arrows on the sign so that it makes more sense, but it's a start. I could probably do with some higher resolution fonts as well, since the signs can be quite large on the screen, but that should be easy enough.

The main issue, however, will be positioning the signs in useful places. Roads often have nodes even if they only join two sections of the same road. Obviously there is no need to put a sign down that confirms you are still on the same road. On the other hand, when a junction is met, where should the sign be placed? This can be calculated by taking the direction the road is coming away from the node in, and placing the sign on the left-hand side of the road. Finding a vector perpendicular to the road is easy in two dimensions, and only slightly harder in three (take the cross product of the direction of the road and the global 'up' vector, that is (0, 1, 0)).