Update app.py

app.py

@@ -936,8 +936,12 @@ window.snapshot = snapshot;
         forceUpdate
     ) {
         if (!mesh.isVerticesDataPresent(BABYLON.VertexBuffer.PositionKind) || !mesh.isVerticesDataPresent(BABYLON.VertexBuffer.NormalKind) || !mesh.isVerticesDataPresent(BABYLON.VertexBuffer.UVKind)) {
-            alert("Cannot call applyDisplacementMap: Given mesh is not complete. Position, Normal or UV are missing "+!mesh.isVerticesDataPresent(BABYLON.VertexBuffer.NormalKind));
-            return mesh;
+            //alert("Cannot call applyDisplacementMap: Given mesh is not complete. Position, Normal or UV are missing");
+            let positions = mesh.getVerticesData(BABYLON.VertexBuffer.PositionKind);
+            let normals = [];
+            BABYLON.VertexData.ComputeNormals(positions, mesh.getIndices(), normals, {useRightHandedSystem: true});
+            mesh.setVerticesData(BABYLON.VertexBuffer.NormalKind, normals);
+            //return mesh;
         }
 
         const positions = mesh.getVerticesData(BABYLON.VertexBuffer.PositionKind, true, true);