Fix for crash while drawing Point manipulator (gizmo) when LibG fails to load

src/DynamoCoreWpf/Rendering/HelixRenderPackage.cs

@@ -79,6 +79,8 @@ public HelixRenderPackage()
         /// Set the transform that is applied to all geometry in the renderPackage.
         /// </summary>
         /// <param name="transform"></param>
+        // TODO: Unused method. Adds unnecessary dependency on ProtoGeometry. Remove in 3.0
+        [Obsolete("This method will be removed in 3.0. Use SetTransform(double[] matrix) instead.")]
         public void SetTransform(Autodesk.DesignScript.Geometry.CoordinateSystem transform)
         {
             var xaxis = transform.XAxis;
@@ -95,12 +97,15 @@ public void SetTransform(Autodesk.DesignScript.Geometry.CoordinateSystem transfo
             this.Transform = csAsMat.ToArray();
         }
 
+
         /// <summary>
         /// Set the transform that is applied to all geometry in the renderPackage
         /// by computing the matrix that transforms between from and to.
         /// </summary>
         /// <param name="from"></param>
         /// <param name="to"></param>
+        // TODO: Unused method. Adds unnecessary dependency on ProtoGeometry. Remove in 3.0
+        [Obsolete("This method will be removed in 3.0.")]
         public void SetTransform(Autodesk.DesignScript.Geometry.CoordinateSystem from, Autodesk.DesignScript.Geometry.CoordinateSystem to)
         {
             var inverse = from.Inverse();
@@ -149,8 +154,14 @@ public void SetTransform(double m11, double m12, double m13, double m14,
 
         /// <summary>
         /// Set the transform as a double array, this transform is applied to all geometry in the renderPackage.
-        /// NOTE: this matrix is assumed to be in row vector form, and will be transformed into the neccesary form
-        /// for helix
+        /// This matrix should be laid out as follows in row vector order:
+        /// [Xx,Xy,Xz, 0,
+        ///  Yx, Yy, Yz, 0,
+        ///  Zx, Zy, Zz, 0,
+        ///  offsetX, offsetY, offsetZ, W]
+        /// NOTE: This method should transform the matrix from row vector order to whatever form is needed by the implementation.
+        /// When converting from ProtoGeometry CoordinateSystem form to input matrix, set the first row to the X axis of the CS,
+        /// the second row to the Y axis of the CS, the third row to the Z axis of the CS, and the last row to the CS origin, where W = 1. 
         /// </summary>
         /// <param name="matrix"></param>
         public void SetTransform(double[] matrix)

src/DynamoManipulation/NodeManipulator.cs

@@ -88,6 +88,31 @@ internal IRenderPackageFactory RenderPackageFactory
         }
 
         internal Point3D? CameraPosition { get; private set; }
+
+        // This is null for each new manipulator that is initialized.
+        private bool? isValidNode;
+
+        /// <summary>
+        /// This property is true if the cached value of the manipulator node is non-null.
+        /// It caches its value so that it doesn't have to repeatedly query the node value.
+        /// NOTE: There could be edge cases where the node value could become null while the
+        /// manipulator is being moved, etc. These cases will not be caught and the boolean
+        /// value returned would be true even though it should change to false. This case could
+        /// lead to a potential crash and is yet to be addressed.
+        /// </summary>
+        private bool IsValidNode
+        {
+            get 
+            {
+                if (isValidNode == null)
+                {
+                    isValidNode = !IsNodeNull(Node.CachedValue);
+                }
+
+                return (bool) isValidNode;
+            }
+
+        }
 
         #endregion
 
@@ -154,7 +179,8 @@ protected virtual void Dispose(bool disposing)
         /// <param name="mouseButtonEventArgs"></param>
         protected virtual void MouseDown(object sender, MouseButtonEventArgs mouseButtonEventArgs)
         {
-
+            if (!IsValidNode) return;
+
             active = UpdatePosition();
 
             GizmoInAction = null; //Reset Drag.
@@ -430,7 +456,7 @@ private RenderPackageCache GenerateRenderPackages()
 
             // This check is required as for some reason LibG fails to load, geometry nodes are null
             // and we must return immediately before proceeding with further calls to ProtoGeometry
-            if (IsNodeValueNull()) return packages;
+            if (IsNodeNull(Node.CachedValue)) return packages;
 
             AssignInputNodes();
 
@@ -551,28 +577,47 @@ public RenderPackageCache BuildRenderPackage()
             return packages;
         }
 
+        #endregion
+
         /// <summary>
         /// Checks if manipulator is enabled or not. Manipulator is enabled 
-        /// only if node is not frozen or not setup as partially applied function 
+        /// only if node is not frozen, its preview visible and value non-null. 
         /// </summary>
         /// <returns>True if enabled and can be manipulated.</returns>
         public bool IsEnabled()
         {
             if (Node.IsFrozen || !Node.IsVisible) return false;
 
-            if (IsNodeValueNull())
+            if (!IsValidNode)
             {
                 return false;
             }
 
             return active;
         }
 
+        // TODO: Remove in 3.0
+        [Obsolete("This method will be removed in 3.0 and will no longer be available as a public API.")]
         public bool IsNodeValueNull()
         {
-            return Node.CachedValue == null || Node.CachedValue.IsNull;
+            return IsNodeNull(Node.CachedValue);
+        }
+
+        private static bool IsNodeNull(MirrorData data)
+        {
+            if (data == null || data.IsNull) return true;
+
+            if (data.IsCollection)
+            {
+                var elements = data.GetElements();
+                foreach (var element in elements)
+                {
+                    if (IsNodeNull(element)) return true;
+                }
+            }
+
+            return false;
         }
-        #endregion
     }
 
 

src/NodeServices/GraphicsDataInterfaces.cs

@@ -261,7 +261,9 @@ void SetTransform(double m11, double m12, double m13, double m14,
         ///  Yx, Yy, Yz, 0,
         ///  Zx, Zy, Zz, 0,
         ///  offsetX, offsetY, offsetZ, W]
-        ///NOTE: This method should transform the matrix from row vector order to whatever form is needed by the implementation.
+        /// NOTE: This method should transform the matrix from row vector order to whatever form is needed by the implementation.
+        /// When converting from ProtoGeometry CoordinateSystem form to input matrix, set the first row to the X axis of the CS,
+        /// the second row to the Y axis of the CS, the third row to the Z axis of the CS, and the last row to the CS origin, where W = 1. 
         /// </summary>
         /// <param name="matrix"></param>
         void SetTransform(double[] matrix);