如何检测 3 个或更多对象是否同时接触（由第四个对象链接）[C# Unity]

Question

How can I tell if 3 or more objects are in touch at the same time?

This is what I'm trying to do:

Let's say you have a game, where there is an eye stone and a moon stone, and they need to be connected to the skull stone to win.

You can use fire stones to extend the reach of the skull stone.

So if you want to win the level, the eye and the moon need to be connected to the skull.

This is what I've tried:

Using OnTriggerEnter2D and a series of bool queries

It does work except for the part that I can't seem to be able to make it check if two or more are connected, for example, it can tell me that the skull is either touching the eye, or the moon, but not both at the same time.

Using Linecast to add objects to an array

This, I assume would work, except that I guess the line would detect any object in line with another object, regardless of distance.

Also, not sure what the most efficient way of adding them into an array to check would be, or even if that would be the best way of checking contact.

Below are some screenshots of what I'm trying to do:

Objects are apart:

Now Skull touches eye and moon, win condition met:

If eye and moon are further apart, player can use fire to extend contact:

Thanks a lot!

Answer 1

I think I've solved it changing Tags on runtime.

So the fire has a script now that it changes its own tag from Fire to Activated Fire if it touches the skull or another activated fire, this is with an OnTriggerStay2D and then the Totem checks to see if an activated fire or the skull is touching it.

It works!

Also, if an ActivatedFire stops touching the Skull it becomes a Fire again

Answer 2

It would appear to me (and please correct me if I'm wrong, and ignore this answer) that your game is grid based, assuming that's the case, you can very easily keep track of your tiles and on a movement/creation/whatever event, scan for nearby neighbors and recursively look for the pattern you are looking for.

If this is the case and your game is grid-based with whole numbers (ints), this approach will likely help you out a lot in the future; as it's very simple, straight forward and dirt cheap performance wise.

Answer 3

In every scene I like to have a 'handler' object with a handler script that is constantly monitoring important objects that have an 'object' script, usually the win condition runs in the handler... in this script I would constantly check for the 'activated' parameter of those objects found in the scene with the 'object' script... This object script inside each object will be controlling individually their 'activated' parameter. Checking in each collision if the colliding object is an 'activated state' or if its the skull.... if so... Then change its own variable or tag to whatever the 'handler script is monitoring... When all objects in the list are in an activated state you win...

Handler.cs: Game starts... Looks for objects that have a' Object.cs' script and saves them into a list of the script type. In a loop the handler is checking the 'activated' variable from the script of each object saved into the list of objects found.... If they are all activated or true.... You win. And you just need to drag and drop prebafs that have the Object.cs script.

Object.cs:

Here check for the collisions, when you collide with something check if that something has an 'Object.cs' script and check their 'activated' variable, if its activated... Cange its own variable to 'activated' or true or how ever you want to check it ik the handler script... In your example all stones need the same condition 'that the thing they are colliding with is in an activated state and that the skull is the first thing in the activated state when game begins... If we want to add many different objects with many different actions... We could just add a case statement that compares each colission different in order to change their activated parameter. Here an example of the concept:

public bool activated;
public string type:
//add extra variables

Start() {
//if my type is = 'skull' then change my activated state to 'truel'... else make it false
//make extra variables false hasFire etc
} 
OnTriggeEnter2D() {
Switch(type) {
case  "fire" :
//check if the thing we collided with has a object script and if the activated variable is true... Ifso then make own variable true and If the objwct touches thw skull everything works fine since thw skull variable has been set in the start method
break;
case  "totem" :
//Same as fire... It just needs to be next to something activated... fire or skull
break;
case  "skullOnlyTotem" :
//thia collision will check if the tag of the objevt we collided is the skull tag... If so the totem is activated, activated fire doesn't work with this tototem because we are not checking the activated parameter only for the skull tag
break;
case  "waterTotem" :
//here we can have a condition that needs only a colission with a object that has a water tag and nothing more 
break;
case "obsidianTotem" :
//here we can have a totem that needs fire and water to be activated since we need two conditions we will add to extra variables to the script, the hasFire bool and the hasWater bool. These will be set to false on start and here we will check their state... First if what we collided is in the activated state then we are next to a fire... if so.. Set hasfire =true then check if that thing we collided has tag =water... If so hasWater = true ; finally
Compare if two conditions are true if so... Set the activated variable to true
break;
case "aLotOfConditions" :
//for ten conditions you will need 10 new variables and set them all to false at start and in each collision check the tag belong to any of its clnditions if so turn variable true... At last check if all true if so... Activate... 
break;
} 
} 

Here we can scale up the functionality a lot just adding more to the case statement and changing the tag names... Making prefabs with diferent image and type name... Then just drop them in the scene.... Two scripts...

Handler - > finds objects and checks activated variable

Object - >has activated variable and checks colissions with a case for every type using a conbination of tags and the activated variable