collision work on one side of an object help

[gordonquinton11]

how do make a collision action of an object work on only one side?
ex: say you are creating a boss for your game, and it's weak spot is on the boss' back. how do you make the boss' back it's weak point?

[Jeff]

I would use another object and have it invisible to detect collisions in that area.

[UltimateWalrus]

If you don't need precision, my preference would be:

Enemy is overlapping Player
+Y Coordinate of Enemy > Y("Player")
--> Enemyestroy

Enemy is overlapping Player
+Y Coordinate of Enemy <= Y("Player")
--> Playerestroy

That'll give you simple goomba-stomping behavior. If you do need precision (say you have to touch a glowing red orb on the boss or something) then use Jeff's method

[gkinfinity]

Just have an event that always sets an invisible object (essentially a hitbox) over a certain part of your enemy. In other words, do what Jeff said.

The method Ultimate Walrus suggested could work too although you'd probably also want to account for both the character's and enemy's X positions as well.

[UltimateWalrus]

Just to clarify the method I suggested would work with n amount of enemies, whereas making the hitbox for more than one enemy would require spread value/fastloops (still a perfectly fine thing to do... I'm just sayin')

Another alternative if you need precision is to use a different frame of your active as the collision mask for the weak spot. Then, in order:
*Set to the frame of your collision mask
*Test for collision
*Set back to the frame you actually want to display
This should work for n amount of enemies without fastloops. I have an example of this type of thing on my website