Calculating Difficulty

[phamtq]

I signed up not too long ago and I think this place is great. I've learned how not to suck too hard which is more helpful than you can imagine. :D

Well, I posted this on the Capcom BBS boards but it looks like people are as stumped as I am.

I've always been curious as to what increasing the difficulty does in a game like Street Fighter. Obviously a lot of people are going to respond and say, "It makes it harder." But what about it makes it harder?

For example other games increase the number of opponents or make their hits cause more damage. Street Fighter obviously can't increase the number of opponents and from the look of things, it doesn't make their roundhouse hit harder than before.

Does it calculate the number of times a certain button is hit and works off of that or does it go through a preset algorithm that's model after human player? Does it "cheat" and know what moves you pressing the moment you press them and uses it against you?

I know setting the difficulty to 1 star makes the opponent block less (or not at all), stand there doing nothing, letting itself get thrown, etc... So does a maximum level of stars indicate that program knows how to do something and why it should do it?

I'm just trying to quantify what difficulty means.

I know all this doesn't help when you're playing against a human opponent but I've just recently beat Street Fighter II at the arcade (yay :party:) and I'm extremely curious about the subject.

[Hitaro0]

It makes mash throws stupidly strong.

[pherai]

When you play the comp a lot, you start to notice some very computer like behavior like psychic blocking and counter poking, yet there are certain tricks the computer simply isn't programmed to know how to deal with. I believe increasing the difficulty simply increases how often your opponent attacks you, and how frequently they can psychic defend against your attacks.

[goodm0urning]

The lower the difficulty level, the higher the ratio of stupid mistakes vs. intelligent decisions the CPU will make. For example: when jumping in on CPU Guile, the computer might narrow its choices down to two programmed responses: flash kick or walk forward. Walking forward would be a stupid mistake. On the other hand, you're probably going to eat that flash kick. Whichever one the computer is more likely to pick probably depends on how high you've set the difficulty.

And I'm pretty sure, at least in the early days, that the damage you took did indeed go up at higher difficulties.

[phamtq]

I believe increasing the difficulty simply increases how often your opponent attacks you, and how frequently they can psychic defend against your attacks.

So in a way, the difficulty sets the computer's pace (more aggressive versus "defensive") with psychic defends?

[Rufus]

Basically, the machine cheats, and then decides how much to let a player win.

That is to say, it's got effectively instantaneous reactions while the best humans will have reaction times around 150ms. It doesn't have to deal with the technical limitations of charge moves. It can time things flawlessly.

Now, while it's possible to build A.I.s that will accurately simulate high level human play, doing so takes a lot of effort, and can be unreliable. As a consequence, the computer players don't really play like humans.

Now, turning up the difficulty can have a variety of effects depending on the game. That includes things like increasing the damage that the computer players deal, decreasing the damage that they take, or shifting the rates of attacking, actively defending, passively defending, and walking into attacks.

There are a slew of options for the way that AI behaves that can modify difficulty, but AFAIK none of the fighting game AI is really that good. (Although I don't have any experience, there are apparently some versions of VF which have exceptionally player-like AI.)

[polarity]

Try setting the computer in 3S or GGXX to level 1 difficulty and notice how much it just stands around doing NOTHING. I think all that varies is that it does that less as you increase the difficulty. It's the same for a lot of modern fighting games, including 3D ones.

Long story short, don't play the computer. ;)

[Infested Jester]

Damage definitely goes up.....Ryu jump HK, crouch HK = 50% of your life gone.......Ken 2 hit DP = 50% of your life + dizzy, etc. :lame:

[epsilon_]

in st and 3s the damage you do goes down, and the damage they do, goes up.

notably terribly ridiculous in st/ae.

[the_dannobot]

Well, here's how I would handle difficulty scaling:

The AI update doesn't happen every frame, it only occurs on a time delta defined by the difficulty level. When the AI updates, it takes into account its position relative to the target character, its current state, and the current state of the target character. Based on that information, it decides on the best course of action and executes it.

To make the game easier, you make the AI update time delta longer. This causes behavior like slower reaction times, missed blocks, less combos and juggles, etc. If you speed up the update time delta the AI will like block/parry whenever possible, combo/juggle after every succesful attack, throw reversal/recovery, etc.

Most games also add things like increased damage scaling, or the KoF which lets the AI read the player's input queue so it knows what moves are coming ahead of time.

[pc1x1]

Well, here's how I would handle difficulty scaling:

The AI update doesn't happen every frame, it only occurs on a time delta defined by the difficulty level. When the AI updates, it takes into account its position relative to the target character, its current state, and the current state of the target character. Based on that information, it decides on the best course of action and executes it.

To make the game easier, you make the AI update time delta longer. This causes behavior like slower reaction times, missed blocks, less combos and juggles, etc. If you speed up the update time delta the AI will like block/parry whenever possible, combo/juggle after every succesful attack, throw reversal/recovery, etc.

Most games also add things like increased damage scaling, or the KoF which lets the AI read the player's input queue so it knows what moves are coming ahead of time.
This makes perfect sense :wow:.
I would say its a culmination of all aforementioned arguments, good AI aka harder settings, normally hits harder, executes vs your actions faster, and normally does the omg impossible moves, that everyone loves, including 1 poke dizzy fun. :smokin:

[pherai]

snip

I don't know what games you are playing, but even on lowest difficulty, SF game computer opponents never demonstrate human like reaction time.

[rising_player]

They get crossed over less easily :lol: