sensor.js

class Sensor {
  constructor(car) {
    this.car = car;
    this.rayCount = 10;
    this.rayLength = 150;
    this.raySpread = Math.PI / 2;

    this.rays = [];
  }

  update(roadBorders,traffic) {
    this.#castRays();
    this.readings = [];
    for (let i = 0; i < this.rays.length; i++) {
      this.readings.push(this.#getReading(this.rays[i], roadBorders,traffic));
    }
  }

  #getReading(ray, roadBorders,traffic) {
    let touches = [];
    for (let i = 0; i < roadBorders.length; i++) {
      const touch = getIntersection(
        ray[0], ray[1], roadBorders[i][0], roadBorders[i][1]
      );
      if (touch) {
        touches.push(touch);
      }
    }

    for(let i=0;i<traffic.length;i++){
      const poly=traffic[i].polygon;
      for(let j=0;j<poly.length;j++){
        const value=getIntersection(
          ray[0],
          ray[1],
          poly[j],
          poly[(j+1)%poly.length]);
        if(value){
          touches.push(value);
        }
      }
    }

    if (touches.length == 0) {
      return null;
    }
    else {
      const offsets = touches.map(e => e.offset);
      const minOffset = Math.min(...offsets);
      return touches.find(e => e.offset == minOffset);
    }

  }

  #castRays() {
    this.rays = [];
    for (let i = 0; i < this.rayCount; i++) {
      const rayAngle = lerp(this.raySpread / 2, -this.raySpread / 2, this.rayCount == 1 ? 0.5 : i / (this.rayCount - 1)) + this.car.angle;
      const start = { x: this.car.x, y: this.car.y };
      const end = { x: this.car.x - Math.sin(rayAngle) * this.rayLength, y: this.car.y - Math.cos(rayAngle) * this.rayLength };
      this.rays.push([start, end]);
    }
  }

  draw(ctx) {
    for (let i = 0; i < this.rayCount; i++) {
      let end = this.rays[i][1];
      if (this.readings[i]) {
        end = this.readings[i];
      }
      ctx.beginPath();
      ctx.lineWidth = 2;
      ctx.strokeStyle = "lightblue";
      ctx.moveTo(this.rays[i][0].x, this.rays[i][0].y);
      ctx.lineTo(end.x, end.y);
      ctx.stroke();

      ctx.beginPath();
      ctx.lineWidth = 2;
      ctx.strokeStyle = "yellow";
      ctx.moveTo(this.rays[i][1].x, this.rays[i][1].y);
      ctx.lineTo(end.x, end.y);
      ctx.stroke();
    }
  }
}