CODEWITHSUNDEEP
c#unity-game-engine
Bryan Chapel
Bryan Chapel

Reputation: 346

Make a gameObject observe and compare a value on multiple gameObjects around it?

Let's say I have a board of pegs that never move, and a disc is dropped from the top, Plinko style. As the disc falls and hits pegs, they generate a random value from 1-6, which is displayed on the peg. Now I want each peg that has a direct neighbor with a matching value to turn purple, like so:

enter image description here

I've attached a game object to each peg called Neighbor Checker, and attached circular colliders as triggers that overlap with their neighbors, like so:

enter image description here

The Neighbor Checker game objects attached to the pegs are setup with a circular collider set as a trigger, and a rigid body 2d set to kinematic, discrete collision detection, and never sleep (this continuous checking seems to make the value checking more accurate, but kills performance and the disc falls and bounces all choppy).

The primary problem that I'm having is accuracy: sometimes 3 or 4 pegs are all neighbors with the same value and one will still be green.

I'm using OnTriggerStay2D (Collider2D neighbor) in the neighbor checker script to monitor the values of the pegs and their neighbors, and changing their colors when the values match, like so:

 void OnTriggerStay2D (Collider2D neighbor) {

         if (neighbor.gameObject.tag == "NeighborChecker") {
             textMesh = transform.parent.gameObject.GetComponentInChildren<TextMesh>();
             neighborTextMesh = neighbor.transform.parent.gameObject.GetComponentInChildren<TextMesh>();
             if (textMesh.text == neighborTextMesh.text) { // Make it purple
                 transform.parent.GetComponent<SpriteRenderer>().color = new Color(.5f,0f, 0.5f);
             } 
             else { // Change it back to the original green starting color
                 transform.parent.GetComponent<SpriteRenderer>().color = startingColor;
             }
         }
     }

Any suggestions on how to increase the accuracy and efficiency here? Am I going about this totally wrong? I've seen this in the Unity docs: Physics2D.OverlapCircleAll, and wonder if I should use this at the start to generate a list of neighbors for each peg, then in update loop through these and check their values, but that might get expensive too so I'm not sure.

This is my first 2D unity project. I was ok with the text based stuff, but the physics is kind of hard to grok even though I've read the documentation inside and out! Any help and suggestions would be greatly appreciated.

Thanks in advance!

Upvotes: 3

Views: 321

Answers (1)

Matthew Loveday
Matthew Loveday

Reputation: 516

If you want to maximise performance you should only be updating the pegs when a change has occurred. You could store all of the pegs in an array (or if you wanted to add more pegs at run-time a list) and then call a function on each Neighbour that would tell it to check it's surroundings, this would reduce the amount of times you're checking the neighbours significantly thus leading to better performing code.

If you were to use Physics2D.OverlapCircle in a custom function you could check what other colliders are overlapping it. So once the ball has registered a collision you would loop through the array using a for loop and call the update function on each ball. It should be noted that you will also need to perform this loop at the start of the game if you want the colours to be updated before the ball collides with a circle.

If you wanted to take it a step further you could call the update function on the one the ball hits, and then within that function update all the colliders returned by [Physics2D.OverlapCircle][1], if you had pegs that were out of the range of the group the ball collides with you would save some performance there.

Upvotes: 1

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