seia0106 wrote:
Hello John,
Thank you for the reply and tip.
If it is possible for your can you please explain a little how the use
of fmod() is changing the ranging from -pi to +pi to '0 to 2pi' now?
fmod isn't changing the range.
Look at the first argument given to fmod. There a constant
of 2*pi is added to the number. The result of atan2 can only
be in the range -pi to +pi. So adding 2*pi gives a range
of pi to 3*pi (note that now the boundary of this range
are both positive) and fmod is used to clamp that down
to [0 to 2*pi[, by taking the remainder of the division with
2*pi.
It really is the same as using % on integer
0 % 5 -> 0
1 % 5 -> 1
2 % 5 -> 2
3 % 5 -> 3
4 % 5 -> 4
5 % 5 -> 0
6 % 5 -> 1
7 % 5 -> 2
8 % 5 -> 3
9 % 5 -> 4
10 % 5 -> 0
11 % 5 -> 1
...
Here the division by 5 leaves us with a remainder which by nature is
always in the range 0 to 4. (If you have 23 apples and 5 kids and you
give each kid an equal amount of apples, how many apples are left. The
answer cannot be greater then 4, because of it were 5 or above, each kid
would get an additional apple, which eventually would bring down the number
of apples left to less then 5)
--
Karl Heinz Buchegger
kb******@gascad.at 
