sensor.js

class Sensor{
    constructor(car){
        this.car = car;
        this.rayCount = 5;
        this.rayLength = 150;
        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="yellow";
            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="black";
            ctx.moveTo(this.rays[i][1].x,this.rays[i][1].y)
            ctx.lineTo(end.x,end.y)
            ctx.stroke();
        }
    }
}