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This is a little bit of Action Script that will give you a basis on which to make a simple AI. I basically guessed and checked until I figured out the correct algorithms. This is based on a set of axes whose center is the symbol this is in. I changed the axes by turning them 90 degrees so you have a new set so that you can decide which quadrant the other symbol is in, and the middle of these quadrants is a direction for this symbol to move to get to it. Made for a 2D game where the symbols go up, down, left, and right.

function locate() { //function name is locate()

xd=this._x-_root.guy1._x //the difference in-between this
symbol's x and the other symbol's

yd=this._y-_root.guy1._y //the difference in-between this
symbol's y and the other symbol's

npx=(xd+yd)/Math.pow(2,1/2) //A little bit of math to change the
corrdinate

npy=(yd-xd)/Math.pow(2,1/2) // "
"

if(npx>=0 && npy>=0) { //Assumes first quadrant identities

this._rotation=0 //set's the symbol facing up (North)

this._y-=2.5 //moves the symbol up

return 1 //returns a value of 1 for first quadrant to be used in
other functions if needed

} else if(npx>=0 && npy<=0) { //Assumes second quadrant identities

this._rotation=270 //Sets the symbol facing left

this._x-=2.5 //moves the symbol to the left

return 2 //return 2 for second quadrant for use in other funcitons

} else if(npx<=0 && npy>=0) { //assumes 4th quadrant identities

this._rotation=90 //sets the symbol facing right

this._x+=2.5 //moves the symbol right

return 4 //returns 4 for 4th quadrant/right

} else { //only quadrant left is down (3rd)

this._y+=2.5 //moves down

this._rotation=180 //sets facing down

return 3 //returns 3 for 3rd quadrant/down

}

}

What this does is set the symbol moving towards the average direction that the other symbol is in. It makes a killer homing device that is very hard to defeat if you have the sprite attack. Speaking of which...

if( (this._x < _root.guy1._x +100 && this._x > _root.guy1._x-100) && (this._y
< _root.guy1._y + 100 && this._y > _root.guy1._y -100)) { //an if statement that
I figured out. If the other symbol is within 100 px of this symbol it will do
the action.

ran=Math.ceil(Math.random()*20)-1 //I added this to only make the symbol
attack some of the time because it was too hard to beat if it was constantly
attacking. can be removed if you wish. the whole math statement can be replaced
with random(20) if you wish, I just couldn't remember the code at the time....

if(ran==0) punch() //remove the if statement if you removed the random above.
the punch() function is my attack function, you will want to make your own
attack functions and put them here

}

Of course, the simplest way to make an AI is to have a lot of different functions that do different things (move, attack...) and then activate them when a condition returns true. I suggest you play around with these to get them how you want, and in the meantime try inventing some of your own. Feel free to modify, use and share the action script in this tutorial, however please don't redistribute this tutorial, just give a link to it please.

Thanks! Luke Knepper (By the way, please visit zazeran.com and give me feedback!)

» Level Intermediate |

Added: 2006-12-05 Rating: 9 Votes: 8 |

» Author |

Luke has experience with Java, Flash/ActionScript, and PHP. Codes and writes programs a lot, enjoys making games. Has a small game website, zazeran.com . |

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