Been trying to create a bit of a battle system, Zelda-style...

I need to "kill" entities within a certain area; roughly one tile in front of my character.

However, I'm not quite sure how to do this; since you can't practically use exact X and Y coords. Is there some way using an IF that I can say "killx is within 10 of entity.x"?

There's also the good ole' mathematical distance formula.

You know,

distance = square_root( a^2 + b^2 )

Where A is the difference in X between the player and the target, and B is the difference in Y.

so a = player.x - enemy.x
b = player.y - enemy.y.

And if the resulting distance is less than ten or whatever, we deal some damage.

Quote:

Though keep in mind you'll still need to check where the character is facing and where the location of the enemy is to that.
But Omni, God, why didn't I think of it? It's positively brilliant.

I'll just add to Omni's thingy:

sqrt() is actually a less-than-fast function. If you're only doing it occasionally then it's not a big deal, but if you're going to do it every single frame, you could probably find better things for those CPU cycles to do.

So, you should just square the distance your checking. In other words:

// Don't use

if(sqrt( (a*a) + (b*b) ) < 10) {

// Use

if((a*a) + (b*b) < 100) {

It'll be faster. You might want to use a weapon_length variable of some kind if you intend to allow different weapon lengths. In this case, just set weapon_length_sq = weapon_length * weapon_length when you switch the weapon, and check against that.

Pre-computation is where it's at! :D

I'm doing something similar:

first i check if attack is possible, then I play the attack animation if it was. Next I do a simple rectangle collision check in the direction the player is facing and in front for the weapons total reach (wont work for thinks that shoot projectiles as it's checking the entire area at once) next I deduct the HP (if any). Finally check for kills and play animations as nessary and move the entites out.

collision detection is pretty simple with rectangles just do a quick google on it and you should find sufficient information.