Step 1: Following the tail of the comet
The very first step to breathe life into our game is to generate the tail of the comet, i.e. the path the hero has to follow.
To do this we have to simulate an endless random spline and make the camera follow the spline at constant speed.
We used a Catmull-Rom spline for that. While traversing the spline, each time you reach a control point you advance the spline by removing the first point and adding a new one at the other end. This new random point is generated by adding random components x,y,z to the last point of the spline. It's a simple and effective process.