Update

Project string on portal to keep navpath on the navmesh

Author: dqnhat

src/Channel.js

@@ -1,21 +1,22 @@
 import { Utils } from './Utils.js';
 
 class Channel {
-  constructor () {
+  constructor() {
     this.portals = [];
   }
 
-  push (p1, p2) {
+  push(p1, p2) {
     if (p2 === undefined) p2 = p1;
     this.portals.push({
       left: p1,
       right: p2
     });
   }
 
-  stringPull () {
+  stringPull() {
     const portals = this.portals;
     const pts = [];
+    const string = [];
     // Init scan state
     let portalApex, portalLeft, portalRight;
     let apexIndex = 0,
@@ -27,7 +28,7 @@ class Channel {
     portalRight = portals[0].right;
 
     // Add start point.
-    pts.push(portalApex);
+    string.push({ index: 0, point: portalApex });
 
     for (let i = 1; i < portals.length; i++) {
       const left = portals[i].left;
@@ -41,7 +42,7 @@ class Channel {
           rightIndex = i;
         } else {
           // Right over left, insert left to path and restart scan from portal left point.
-          pts.push(portalLeft);
+          string.push({ index: leftIndex, point: portalLeft });
           // Make current left the new apex.
           portalApex = portalLeft;
           apexIndex = leftIndex;
@@ -64,7 +65,7 @@ class Channel {
           leftIndex = i;
         } else {
           // Left over right, insert right to path and restart scan from portal right point.
-          pts.push(portalRight);
+          string.push({ index: rightIndex, point: portalRight });
           // Make current right the new apex.
           portalApex = portalRight;
           apexIndex = rightIndex;
@@ -80,6 +81,27 @@ class Channel {
       }
     }
 
+    //Project string on the portals
+    if (string.length == 1) pts.push(string[0]["point"]);
+    for (let i = 1; i < string.length; i++) {
+      for (let j = string[i - 1]["index"]; j < string[i]["index"]; j++) {
+        const a = string[i - 1]["point"];
+        const b = string[i]["point"];
+        const c = portals[j].left;
+        const d = portals[j].right;
+
+        if (Utils.vequal(c, d)) {
+          pts.push(c);
+          continue;
+        }
+
+        const project = Utils.p4intersect(a, b, c, d);
+
+        if (project)
+          pts.push(project);
+      }
+    }
+
     if ((pts.length === 0) || (!Utils.vequal(pts[pts.length - 1], portals[portals.length - 1].left))) {
       // Append last point to path.
       pts.push(portals[portals.length - 1].left);