I've been studying the Earthball script and have been messing with the coding so that I may understand C-lite better. Everything in Earthball makes sense to me excluding the final few lines where the camera movement is calculated.

Before function main() there is a VECTOR defined


the following is in function main() in while(1)


I understand the key_force and mouse_force functions but I'm not sure how vec_accelerate works in this example.

It seems to me that vMove would be 0 at this point since it's never called or calculated before vec_accelerate, the same with vAngularSpeed. I'm confused because if the distance argument (vMove) and the speed arguement (vAngularSpeed) are 0 then what is the point of vec_accelerate at this point?

I'm sure this is very simple I'm just new to Gamestudio and vector's so I'm confused as to what is going on here.

I know what is happening here (we're calculating our rotation and accelerating it based off the arrow keys and mouse movement) I just can't seem to put 2+2 together.

And for that matter, what exactly does VECTOR do, I can't seem to find it in the documentation.

The next section of code is very similar to this so I'm hoping if I can make sense of this I can figure out the next as well.

did I ask the question improperly? Basically I don't understand the vectors vAngularSpeed and vMove since they don't seem to have any values input to them before they're called in the while(1) statement.

They do not have to have values, because thoses are the vectors that are calculated by vec_accelerate.

The first two parameters are used as return values, thus you would use the distance vector for your c_move instruction.
The speed vector is an input and return value at the same time, because it is used for the next calculation iteration of the vec_accelerate and also modified by it. At the beginning of an acceleration the speed of an object is zero (in most cases). You could set it to something nonzero if your object is either already moving or if you want it that way (for whatever reasons).

the last two parameters (accel and friction) are just used for input and calculation.

Hope this clears it up a little bit.
By the way: This is all covered in the manual:
http://www.conitec.net/beta/avec_accelerate.htm

But I also admit that sometimes the manual is a litte bit confusing (and for beginners maybe even more).

Hope you are not mad at me now

edit:
The calculation is explained more detailed at the accelerate instruction (which is the same but just for one dimension):
http://www.conitec.net/beta/aaccelerate.htm