I can't make collisions work in p5js with circles

Question

I have followed the instructions of a "TheCodingTrain" tutorial, it describes how to calculate the distance between two circles to emulate collisions. I have a lot more, but this is the code I have pertaining to my problem.

  playerPos = createVector(width * 0.2, height / 2, 60);
  enemyPos1 = createVector(width * 0.8, height / 2, 40);

  d = dist(playerPos.x,playerPos.y,enemyPos1.x,enemyPos1.y);

  circle(playerPos.x, playerPos.y, playerPos.z);
  circle(enemyPos1.x, enemyPos1.y, enemyPos1.z);

  if( d < playerPos.z/2 + enemyPos1.z/2){
     enemyPos1.x++
  }

I tried the code above, it did not make the position of the smaller circle change. I was expecting it to move. I have gone through and I haven't identified any problems with the code.

Answer 1

You don't have any code to create movement. You have two circles which don't overlap, and aren't moving so will not overlap. Generally one uses a velocity vector that is added to the position to create movement. Then, when the circles actually overlap, your collision detection code will work:

let playerPos, enemyPos1;

function setup() {
  createCanvas(400, 400);
  playerPos = createVector(width * 0.2, height / 2, 60);
  enemyPos1 = createVector(width * 0.8, height / 2, 40);
  playerSpd = createVector(1, 0, 0);
  enemySpd1 = createVector(-1,0,0);
}

function draw() {
  background(255);
  d = dist(playerPos.x, playerPos.y, enemyPos1.x, enemyPos1.y);

  circle(playerPos.x, playerPos.y, playerPos.z);
  circle(enemyPos1.x, enemyPos1.y, enemyPos1.z);

  if (d < playerPos.z / 2 + enemyPos1.z / 2) {
    console.log("hit");
  }
  
  playerPos = playerPos.add(playerSpd);
  enemyPos1 = enemyPos1.add(enemySpd1);
}