I'm trying to develop a game where cars move along roads and stop according to the signal of the traffic lights. They've got different velocities. Sometimes cars need to decelerate in order to not hit the leading car. They need to stop at the red lights. They have to make turns and etc. This is all relatively easy when working with straight intersecting roads. But how can I move a car/cars along a curved path? So far it was easy because I was just using either x or y of a car's position. But this time it's not the case, both coordinates seem to be necessary for moving it ahead. With straight roads I can just give a car an arbitrary speed and it will move along x or y axis with that speed. But how can I determine the velocity, if both coordinates have to be taken into account? Acceleration and decelerations are also mistery to me in this case. Thanks ahead.
Although this is about moving a train over a freeform track, the same issues and principles apply to cars moving across freeform roads. Actually, cars may be easier because they don't need to stick to their track 100% accurately.
In short: it's not easy, but doable. How hard it is going to be depends on how realistic you want your cars to look and finding corners to cut.
In your case the cars should simply follow a path (series of points). Since CCActions are bad for frequent direction/velocity changes, you should use your own system of detecting path points and heading to the next. Movement along a bezier curve is not going to have your cards move at constant speed, that rules out the CCBezier* actions.