fix vertical problems in Mesh triangulation

iTowns · Oct 21, 2021 · 4f0a286 · 4f0a286
1 parent 33f8680
commit 4f0a286
Showing 1 changed file with 22 additions and 1 deletion.
diff --git a/src/Converter/Feature2Mesh.js b/src/Converter/Feature2Mesh.js
@@ -274,8 +274,29 @@ function featureToPolygon(feature, options) {
 
         const geomVertices = vertices.slice(start * 3, end * 3);
         const holesOffsets = geometry.indices.map(i => i.offset - start).slice(1);
+        const normal = new THREE.Vector3(0, 0, 0);
+        for (let i = 1; i < count; i++) {
+            normal.x += (geomVertices[3 * (i - 1) + 1] - geomVertices[3 * i + 1]) *
+                (geomVertices[3 * (i - 1) + 2] + geomVertices[3 * i + 2]);
+            normal.y += (geomVertices[3 * (i - 1) + 2] - geomVertices[3 * i + 2]) *
+                (geomVertices[3 * (i - 1) + 0] + geomVertices[3 * i + 0]);
+            normal.z += (geomVertices[3 * (i - 1) + 0] - geomVertices[3 * i + 0]) *
+                (geomVertices[3 * (i - 1) + 1] + geomVertices[3 * i + 1]);
+        }
+        normal.normalize();
+        const pt0 = new THREE.Vector3(geomVertices[0], geomVertices[1], geomVertices[2]);
+        for (let i = 1; i < count; i++) {
+            const ptIn = new THREE.Vector3(geomVertices[3 * i],
+                geomVertices[3 * i + 1],
+                geomVertices[3 * i +  2]);
+            let v = ptIn - pt0;
+            v -= normal.dot(v) * normal;
+            const ptOut = ptIn + v;
+            geomVertices[3 * i] = ptOut.x;
+            geomVertices[3 * i + 1] = ptOut.y;
+            geomVertices[3 * i + 2] = ptOut.z;
+        }
         const triangles = Earcut(geomVertices, holesOffsets, 3);
-
         const startIndice = indices.length;
         indices.length += triangles.length;