Hello again!
SupSuper or Warboy, could you please take a look on that?
I remember that I've read hear on the forum, that there is no reason to try and load the state of the battlescape and try to save units, because you save the seed. I've taken a look into the code, because I was wandering what random generator are you using ( would it be a mersenne twister, or some simple noncryptographic randomizer ) and found out that you are using a global seed (at least for the battlescape). I immedieately have found a way to trick your anti cheating security done with saving the seed.
Scenario 1:
1) alien, and two of my soldiers see it, my turn
2) I save the game.
3) I shot with guy1. I miss. Alien retaliates. My guy dies.
4) I load. I shot with guy1. I miss. Alien retaliates. My guy dies.
5) I load. I take guy3, that is somewhere far away. I shot a random wall.
6) I shot with guy1. I miss. Alien retaliates.
ALIEN MISSSESWhy this happens in detail?
1) Lets say my seed is A, and because of that the sequence of numbers generated is B,C,D,E,F,G,...
2) You have saved a global seed, so no matter who uses the random number, the sequence goes forward.
3) in scenario 1, right after I save the game, guy1 gets value B from the RNG and he misses. Alien gets value C, and hits.
then I load the game, so the seed is again A, guy1 gets value B from the RNG and he misses (again) and the alien gets C, so he hits.
then I load the game, so the seed is again A, guy3 shoots the wall getting B from RNG,
guy1 gets C and he misses, but
alien gets D (no juvenile humor here!) and misses.
I have came up with multiple scenarios of this, and the only way to handle this properly is to keep an instance of a random number generator in each of the battle units.
Let's take the same scenario, with a random number generator instance per a battle unit, shall we?
alien has seed A, guy1 has seed G and guy3 has seed M.
Scenario 1 with an instance of a random generator per a battle unit.
1) alien, and two of my soldiers see it, my turn
2) I save the game. ( with all the different seeds for each unit )
3) I shot with guy1(he has A, so his generator generates B). I miss. Alien retaliates (it has seed G, so he gets number H, and hits). My guy dies.
4) I load. I shot with guy1(he has A, so his generator generates B). I miss. Alien retaliates (it has seed G, so he gets number H, and hits). My guy dies.
5) I load. I take guy3, that is somewhere far away. I shot a random wall(he has seed M, hence getting number N and not changing the next value that the alien and guy1 will get).
6) I shot with guy1(I loaded, so his seed is A, and he gets B from RNG, because he has his own seed). I miss. Alien retaliates(he has his own seed G so he gets H again and hits!
). my guy dies
a lazy fix would just be to have an int in each battle unit named _seed and get his test values by a method like:
int BattleUnit::GenerateOwnRandomNumber()const
{
srand(_seed);
_seed = rand();
return _seed;
}
but I would advise using an object, because this method is "a bit" slow. You can try something from <random> header (c++11), or if you wait a day or two I will get you a nice, and small piece of code ( compact in size and fast ) random generator, that isn't cryptographic, but had nice results... I just need to find that implementation on my email
Regards,
djemon_lda
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