magnetic powerup (pulling coins towards character)

Unity Engine
1

hi guys i m trying to make power up like in subway surfer or temple run MAGNET one.
when ever character picks up the magnet powerup i want my character to pull the coins near by him.
how can i achieve this one any help would be great.

tks a lot in advance.
:slight_smile:

2 
if(Vector3.Distance(transform.position, player.position) < dist)
{
      transform.position = Vector3.MoveTowards(transform.position, player.position, Time.deltaTime * coinSpeed);
}

The vector3 distance check if we a within a given range, if we are we use interpolation to move towards our player at a given speed (coinSpeed). Just make sure that the coin is faster than the player.

:wink:

3

Lots of coins checking Distance every frame could be expensive. Attaching triggers and using OnTriggerEnter() on the coins could be a cheaper option.

4

I am not sure that collision checks will be cheaper.

5

well, im guessing the quickest way is simply to use Physics.OverlapSphere and then just check if the object is indeed a coin

6

hi guys i did something like this when i gets magnet power up my coins collider get bigger in radius and when ever character enters the sphere collision it moves toward the character n gets destroy. do u guys think this will be expensive? tks

7 
using UnityEngine;
using System.Collections;

public class Coins : MonoBehaviour {

    RunnerGame game;
	PlatformerCharacter2D char2D;

    void Awake()
    {
        game = GameObject.Find("Main Camera").GetComponent<RunnerGame>();
		char2D = GameObject.FindGameObjectWithTag("Player").GetComponent<PlatformerCharacter2D>();
    }
	void Update ()
	{
		if (game.CoinMagnet  !char2D.dead)
			if(Vector3.Distance(transform.position, GameObject.FindGameObjectWithTag("Player").transform.position) < 5)
				transform.position = Vector3.MoveTowards(transform.position, GameObject.FindGameObjectWithTag("Player").transform.position, Time.deltaTime *10);
	}
    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.tag == "Player")
        {            
            game.Coins += 1;
            Destroy(this.gameObject);
        }
    }
}

I hope this will be helpfull

3 Likes
8

Physics.Overlap shere will do the job perfectly.

Also checking distance on every frame isn’t that expensive at all.

9

Physic engine works using trees, splitting the world into smaller chunk. So when you do any physic call, you’re not checking everything, but only stuff within specific tree nodes.

Also, I would advice using sqrMagnitude over Magnitude or Distance when doing comparison.

10

This is very useful

11

GameObject.FindGameObjectWithTag() is very slow, caching the object in a GameController singleton would be a much smarter/faster way to handle that. Also (distance1-distance2)…sqrMagnitude < distanceAway is faster than Vector3.Distance

12

ish…

hes only doing it once in awake… there are however other problems with that approach of course.