sensor.js

class Sensor{

    constructor(car){
        this.car=car;
        this.rayCount=8
        this.rayLength=130;
        this.raySpread=Math.PI/2

        this.rays=[]
        this.readings=[];
;
    }

    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="blue"
            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="red"
            ctx.moveTo(
                this.rays[i][1].x,
                this.rays[i][1].y
            )
            ctx.lineTo(
               end.x,
               end.y
            )
            ctx.stroke();
        }
    }

}