Calculate which of coords in object is closest to choosen coords

Question

I have some objects in array with coordinates.

var players = [
{x:100, y:100, pid:1},
{x:-100, y:200, pid:2},
{x:600, y:1200, pid:3}
]

var mousepos = {x:50, y:0} var selected = null

And I want to calculate which of these objects have closest coordinates to mousepos to select it pid selected = pid of closest coords to mousepos

if anyone could give me easy done code?

Possible duplicate of [Get distance between two points in canvas](https://stackoverflow.com/questions/20916953/get-distance-between-two-points-in-canvas) — Federico klez Culloca, Oct 04 '19 at 14:42

score 0 · Answer 1 · answered Oct 04 '19 at 14:51

0

Mate here is the answer. Use the distance formula to calculate the distance between points. One with the smallest distance is the closest point.

Fomula :- Sqrt((x₂-x₁)² + (y₂-y₁)²)

answered Oct 04 '19 at 14:51

surya teja

1
2

Value sometimes is NaN do you know why? also how can i select players.pid then? – Zimek Oct 04 '19 at 15:02
@Zimek "Value is sometimes NaN" when? For what inputs? – Federico klez Culloca Oct 04 '19 at 15:21
@Zimek Well NaN means not a number so. What you can do is make sure all the numbers before testing. – surya teja Oct 04 '19 at 19:35

brk · Answer 2 · 2019-10-04T15:12:09.443

It seems you are trying to calculate Euclidean Distance. If so then you can use Math build in object. Once the distance is calculated then you can return the index. Using this index retrieve the he object from the players

var players = [{
    x: 100,
    y: 100,
    pid: 1
  },
  {
    x: -100,
    y: 200,
    pid: 2
  },
  {
    x: 600,
    y: 1200,
    pid: 3
  }
]
var mousepos = {
  x: 50,
  y: 0
}

function calculateEuclidean() {
  let selectedPid = 0;
  players.forEach(function(item, index) {
    let distance = Math.sqrt(Math.pow((item.x - mousepos.x), 2) + Math.pow((item.y - mousepos.y), 2))
    if (index === 0) {
      selectedPid = index
    } else if (distance < selectedPid) {
      selectedPid = index;
    }
  })
  return players[selectedPid];
}


console.log(calculateEuclidean())

I want as return the pid of player that is closest not distance — Zimek, Oct 04 '19 at 15:10

score 0 · Accepted Answer · answered Oct 04 '19 at 15:49

Working example given by random from discord

    let closestPlayer = undefined;
    let closestDist = undefined;
    for (let i = 0; i < players.length; i++) {
      let player = players[i];
      let distance = Math.hypot(player.x - mousepos.x, player.y - mousepos.y);
      if (closestPlayer == undefined || distance <= closestDist) {
        closestPlayer = player;
        closestDist = distance;
      }
    }
      console.log(closestPlayer)

Calculate which of coords in object is closest to choosen coords

3 Answers3