let HALF_FOV = FOV / 2;

let MAG = 100;

​

class Player {

  constructor(pos) {

    this.pos = pos;

    this.speed = 0.25;

    this.angle = 0;

  }

  draw() {

    fill(color(255,255,255))

    circle(this.pos.x, this.pos.y, 20);

    this.drawFov();

  }

  getAngleFov() {

    return createVector(this.pos.x + cos(this.angle) * MAG, this.pos.y + sin(this.angle) * MAG);

  }

  drawFov() {

    let des = this.getAngleFov();

    line(this.pos.x, this.pos.y, des.x, des.y)

    let halfLeft = createVector(this.pos.x + cos(this.angle - HALF_FOV) * 100, this.pos.y + sin(this.angle - HALF_FOV) * 100)

    line(this.pos.x, this.pos.y, halfLeft.x, halfLeft.y)

    let halfRight = createVector(this.pos.x + cos(this.angle + HALF_FOV) * 100, this.pos.y + sin(this.angle + HALF_FOV) * 100)

    line(this.pos.x, this.pos.y, halfRight.x, halfRight.y)

  }

}

​

class Obstacle {

  constructor(pos) {

    this.pos = pos;

  }

  draw() {

    circle(this.pos.x, this.pos.y, 20)

  }

}

​

var player;

var obstacles = [];

​

function setup() {

  createCanvas(400, 400);

  player = new Player(createVector(width / 2, height / 2))

  obstacles.push(new Obstacle(createVector(width / 4, height / 4)));

  obstacles.push(new Obstacle(createVector(width - width / 4, height - height / 4)));

}

​

function draw() {

  background(220);

  movePlayer();

  player.draw();

  for(let i = 0; i < obstacles.length; i++) {

    if (isInsideFov(player.pos, player.getAngleFov(), obstacles[i].pos)) {

      fill(color(255,0,0))

    } else {

      fill(color(255,255,0))

    }

    obstacles[i].draw()

  }

}

​

function isInsideFov(origin, view, target) {

  let targetDistance = p5.Vector.sub(target, origin)

  let viewDistance = p5.Vector.sub(view, origin)

  let dotProduct = p5.Vector.dot(targetDistance, viewDistance)

  let totalMag = targetDistance.mag() * viewDistance.mag();

  let result = dotProduct / totalMag;

  let angleInRad = acos(result);

​

  if (angleInRad < HALF_FOV && targetDistance.mag() < MAG) {

    return true;

  }

  return false;

}

​

function movePlayer() {

  let dx = 0, dy = 0;

  if (keyIsDown(UP_ARROW)) {

    dy = +sin(player.angle) * (player.speed * deltaTime);

    dx = +cos(player.angle) * (player.speed * deltaTime);

  }

  if (keyIsDown(DOWN_ARROW)) {

    dy = -sin(player.angle) * (player.speed * deltaTime);

    dx = -cos(player.angle) * (player.speed * deltaTime);

  }

  if (keyIsDown(LEFT_ARROW)) {

    player.angle -= 0.01 * (player.speed * deltaTime);

  }

  if (keyIsDown(RIGHT_ARROW)) {

    player.angle += 0.01 * (player.speed * deltaTime)

  }

  player.pos.x += dx;

  player.pos.y += dy

}