Distance Checking for Each Object Separately.

[ogu]

Ok, so I have a little problem, let's say I have two actives: one is calles "Enemy" and the other "Player". I want to have many instances of "Enemy" That appear over time, and I have this action:

Condition: Check if the distance of Enemy is less than 100
Action: Run away!

I set up the condition as a comparison of two general values:

Sqr(((X( "Enemy" )-X( "Player" )) pow 2)+((Y( "Enemy" )-Y( "Player" )) pow 2))

And the Action to run away is executed using Advanced Direction Object by setting the direction to:

LongDir( "Advanced Direction Object", X( "Player" ), Y( "Player" ), X( "Enemy" ), Y( "Enemy" ))

This works perfectly if I just have one instance of Enemy..the problems arise when I have various instances:

Problem 1: If I have, say, 3 "Enemy" objects, the event can only be triggered by one (the most recently created one)... So if for example, another enemy object is close to me it won't do anything... it has to be that one enemy.
Problem 2: When the event does trigger, the action applies to every "Enemy" object and not just the one that triggered the event.

I know I'm doing something wrong, I just can't find what (I'm new to MMF, been using it for a couple of days). What would you recommend I try?

Thanks in advance.

[Brandon]

You need to use object looping for it to work with several different objects. MMF2 has a built-in object selection system that works on single actives when there is something to identify them from the rest. To do this, most people will start an "ID" loop to differentiate the actives if they need to. Here is what you could do:

+Start of Frame
-Spread 0 in Alterable Value A of Enemy (This is you ID)

+Always
-Start loop "ID" Number of Enemy times

+On loop "ID"
+Alterable Value A of Enemy = LoopIndex("ID")
+Sqr(((X( "Enemy" )-X( "Player" )) pow 2)+((Y( "Enemy" )-Y( "Player" )) pow 2)) < 100
-Run

[Popcorn]

Hey and welcome to the forums!

EDIT: OK, Brandon beat me. Now you get two identical replies..

First off, MMF2 comes with a built in extension that find the direction between 2 objects for you. But you allready have the expression so I guess you don't need that now

Anyway, to test for multiple instances at the same time you have to learn how to use fastloops. If you come from a programming language, fastloop can be decribed as a for loop.

Here's how I would it:

Name Enemy's alterable value A to ID. You can do that in the object's property settings in the frame editor.

* Always
- Enemy: spread 0 into ID

* Always
- Start loop "Enemyunit" (number of Enemy) times

* on loop "Enemyunit"
+ Enemy: ID equals loopindex["Enemyunit"]
+ Sqr(((X( "Enemy" )-X( "Player" )) pow 2)+((Y( "Enemy" )-Y( "Player" )) pow 2))
- ADO: LongDir( "Advanced Direction Object", X( "Player" ), Y( "Player" ), X( "Enemy" ), Y( "Enemy" ))


If you don't understand this, do some reading about fastloops
OBS: You cannot spread values and start a loop in the same event. That's why I have two always conditions.

[Dynasoft]

There is another, simpler solution too.
// Set the "D" of every enemy to their distance from the player
Always:
-Set Alterable Value D of Enemy to Sqr(((X( "Enemy" )-X( "Player" )) pow 2)+((Y( "Enemy" )-Y( "Player" )) pow 2))
// Compare to their "D" (Distance) from the player
Compare to Alterable D of Enemy <= 100
-Run Away

In short the problem is that "compare two general values" only tests ONE object. To test them all, you can either use loops to test the objects one-by-one (the usual solution), or you can store what you want to test in an alterable value and use "Compare to Alterable" to test all the objects at once.
Note that if there is more than one of both kinds of object (many on many) then you can't avoid using loops.
EDIT: To do something on the "nearest" enemy, the easiest way is to store their distance in an alt value and use the "Select Object" (released extensions forum) to select the enemy with the lowest alt value.

[Jaffob]

First off, MMF2 comes with a built in extension that find the direction between 2 objects for you.

Out of curiosity, what extension is this?

[Popcorn]

First off, MMF2 comes with a built in extension that find the direction between 2 objects for you.

Out of curiosity, what extension is this?

Clickteam Movement Controller

[ogu]

First off, MMF2 comes with a built in extension that find the direction between 2 objects for you.

Out of curiosity, what extension is this?

Clickteam Movement Controller

Also Advanced Direction Object, but somehow it made stuff act weird so I stuck to my formula :P

@Everyone: Thanks for the help, I'll try looping then. Sounds simple enough.