Making Game AI

[Scott]

I'm just messing around with OpenGL and making a simple pong game and I am wondering how you would make AI for a game using C++, specifically the other paddle in a pong game.
_________________
Tutorial Management Script - Version 1.3 Released
TutorialToday - Up and running, submit your tutorials!
Linux Tutorials - Coming Soon

[Pie32]

AI I think is really tricky business, and even harder to program well. But, something for Pong is actually really simple. Back when I made a simple Pong clone, my AI was simply, "if the center of the ball is above the center of your paddle, move up; else if the center of the ball is below the center of your paddle, move down."

I would start with something like that. If your Pong game is as bad as mine was, that will make an impossible to beat AI. However, if your ball physics are better than constant speed and bounces that don't change the angle of the ball, then you may want to make some tweaks, such as maybe moving the paddle to the center when the ball is going away from it and then trying to keep in level with ball if it moves beyond x pixels of the center.
_________________
[img]http://luneknight.com.ru/counter.jpg[/img]
Random Battle: [img]http://luneknight.com.ru/l.jpg[/img] vs. [img]http://luneknight.com.ru/r.jpg[/img]

[Scott]

Well I basically used what you said but made it a bit more beatable. I made the paddle (moves at 0.20f) move slower than the ball (moves at 0.25f).

I also made it so the paddle only moves when the ball is coming towards it.

Also, it only moves if the ball is above 60% of the paddle or below 40% of the paddle. So if it is in the middle 20% of the paddle then it won't move. If that made sense...
_________________
Tutorial Management Script - Version 1.3 Released
TutorialToday - Up and running, submit your tutorials!
Linux Tutorials - Coming Soon

[Pie32]

Yeah, that was what I was trying to get across at the end when I said to only move the paddle if the ball is x pixels away from the center.
_________________
[img]http://luneknight.com.ru/counter.jpg[/img]
Random Battle: [img]http://luneknight.com.ru/l.jpg[/img] vs. [img]http://luneknight.com.ru/r.jpg[/img]

[LP-SolidRaven]

You should also make the pad move a bit randomly while the ball is at the other side
_________________

[flaran]

It seems that there are two practical limiters for AI at this level.

One is to make certain cases where it is impossible for the AI to win. In this case you can make it so that if the paddle is, say, at the bottom of the screen and you hit it towards the top it is incapable of moving it up fast enough. This way can work but players soon figure out patterns that will beat the AI every time. That makes this method a lot less effective.

There is also the choice of randomizing the effectiveness of the AI. This way, the bot will occasionally make mistakes (ex: hesitating or misjudging the location of the ball). As difficulty progresses, that chance of mistakes can lower.

I've thought about other ways of approaching AI for different games but these are the ones that really apply to pong from my point of view.