Improved PointTrack calculations

*Improved PointTrack rotation calculations to include curved tracks
*Fixed PointTrack not having len property
*Fixed swaped arguments in Vector3.atanY

src/model/tracks/point-track.js

@@ -11,14 +11,29 @@ export default class PointTrack extends Track
     };
 
     constructor(id, start, end, r, nextid, previd, id_station, start_slope, end_slope, id_isolation, prefab_name, maxspeed, derailspeed) {
-        const ry = AngleHelper.radToDeg(start.atanY(end));
-        const rot = new Vector3(0, ry, 0);
-        // TODO: fix rx and rz = 0
-        // TODO: calculate length
-        super(id, start, rot, null, r, nextid, previd, id_station, start_slope, end_slope, id_isolation, prefab_name, maxspeed, derailspeed);
+        const [rot, len] = PointTrack._getRotLen(start, end, r);
+        super(id, start, rot, len, r, nextid, previd, id_station, start_slope, end_slope, id_isolation, prefab_name, maxspeed, derailspeed);
 
         Object.assign(this.points, {
             start, end
         });
     }
+
+    static _getRotLen(start, end, r) {
+        // TODO: include track slope in calculations
+        const pointsAngle = start.atanY(end);
+
+        if(r === 0) {
+            const rot = new Vector3(0, AngleHelper.radToDeg(pointsAngle), 0);
+            const len = start.distance(end);
+
+            return [rot, len];
+        }
+
+        const len = Math.abs(2 * r * Math.asin(start.distance(end) / (2 * r)));
+        const ry = pointsAngle + len / (r * 2);
+
+        const rot = new Vector3(0, AngleHelper.radToDeg(ry), 0);
+        return [rot, len];
+    }
 }

src/model/vector3.js

@@ -88,7 +88,7 @@ export default class Vector3 {
     atanY(other) {
         const dx = other.x - this.x;
         const dz = other.z - this.z;
-        return Math.atan2(dz, dx);
+        return Math.atan2(dx, dz);
     }
 
     add(other) {