Create sensor.js

sensor.js

@@ -0,0 +1,111 @@
+class Sensor{
+    constructor(){
+        this.rayCount=5;
+        this.rayLength=150;
+        this.raySpread=Math.PI/4;
+
+        this.rays=[];
+        this.readings=[];
+    }
+
+    update(x,y,angle,roadBorders,traffic){
+        this.#castRays(x,y,angle);
+        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=[];
+
+        roadBorders.forEach(border => {
+            for(let i=1;i<border.length;i++){
+                const touch=getIntersection(
+                    ray[0],
+                    ray[1],
+                    border[i-1],
+                    border[i]
+                );
+                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(x,y,angle){
+        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)
+            )+angle;
+
+            const start={x,y};
+            const end={
+                x:x-Math.sin(rayAngle)*this.rayLength,
+                y: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.strokeStyle="black";
+            ctx.moveTo(
+                this.rays[i][1].x,
+                this.rays[i][1].y
+            );
+            ctx.lineTo(
+                end.x,
+                end.y
+            );
+            ctx.stroke();*/
+        }
+    }
+}