Consolidate wireframe data validation

Some tests were duplicated between VisWireframe and the code that
consumed the data.  We now expose the Validate function as a public
interface, and invoke it from WireframeObject.  Failed validation
results in a null object being returned, which was previously allowed
but not actually checked for.

PluginCommon/Interfaces.cs

@@ -369,6 +369,8 @@ namespace PluginCommon {
         IntPair[] GetEdgeFaces();
         int[] GetExcludedVertices();
         int[] GetExcludedEdges();
+
+        bool Validate(out string msg);
     }
 
     /// <summary>

PluginCommon/VisWireframe.cs

@@ -190,6 +190,10 @@ namespace PluginCommon {
                 msg = "no vertices defined";
                 return false;
             }
+            if (mVerticesX.Count != mVerticesY.Count || mVerticesX.Count != mVerticesZ.Count) {
+                msg = "inconsistent vertex arrays";
+                return false;
+            }
 
             // check points
             foreach (int vi in mPoints) {
@@ -234,6 +238,10 @@ namespace PluginCommon {
                     return false;
                 }
             }
+            if (mNormalsX.Count != mNormalsY.Count || mNormalsX.Count != mNormalsZ.Count) {
+                msg = "inconsistent normal arrays";
+                return false;
+            }
 
             // check excluded vertices
             for (int i = 0; i < mExcludedVertices.Count; i++) {

SourceGen/Visualization.cs

@@ -203,7 +203,11 @@ namespace SourceGen {
             } else {
                 Debug.Assert(parms != null);
                 WireframeObject wireObj = WireframeObject.Create(visWire);
-                CachedImage = GenerateWireframeImage(wireObj, THUMBNAIL_DIM, parms);
+                if (wireObj != null) {
+                    CachedImage = GenerateWireframeImage(wireObj, THUMBNAIL_DIM, parms);
+                } else {
+                    CachedImage = BROKEN_IMAGE;
+                }
             }
             Debug.Assert(CachedImage.IsFrozen);
         }

SourceGen/WireframeObject.cs

@@ -105,8 +105,15 @@ namespace SourceGen {
         /// Creates a new object from a wireframe visualization.
         /// </summary>
         /// <param name="visWire">Visualization object.</param>
-        /// <returns>New object.</returns>
+        /// <returns>New object, or null if visualization data fails validation.</returns>
         public static WireframeObject Create(IVisualizationWireframe visWire) {
+            if (!visWire.Validate(out string msg)) {
+                // Should not be here -- visualizer should have checked validation and
+                // reported an error.
+                Debug.WriteLine("Wireframe validation failed: " + msg);
+                return null;
+            }
+
             WireframeObject wireObj = new WireframeObject();
 
             wireObj.mIs2d = visWire.Is2d;
@@ -125,11 +132,6 @@ namespace SourceGen {
                 float[] normalsY = visWire.GetNormalsY();
                 float[] normalsZ = visWire.GetNormalsZ();
 
-                if (normalsX.Length != normalsY.Length || normalsX.Length != normalsZ.Length) {
-                    Debug.Assert(false);
-                    return null;
-                }
-
                 for (int i = 0; i < normalsX.Length; i++) {
                     wireObj.mFaces.Add(new Face(normalsX[i], normalsY[i], normalsZ[i]));
                 }
@@ -139,14 +141,6 @@ namespace SourceGen {
             float[] verticesY = visWire.GetVerticesY();
             float[] verticesZ = visWire.GetVerticesZ();
             int[] excludedVertices = visWire.GetExcludedVertices();
-            if (verticesX.Length == 0) {
-                Debug.Assert(false);
-                return null;
-            }
-            if (verticesX.Length != verticesY.Length || verticesX.Length != verticesZ.Length) {
-                Debug.Assert(false);
-                return null;
-            }
 
             // Compute min/max for X/Y for 2d re-centering.  The trick is that we only want
             // to use vertices that are visible.  If the shape starts with a huge move off to
@@ -173,11 +167,11 @@ namespace SourceGen {
                 int v0index = edges[i].Val0;
                 int v1index = edges[i].Val1;
 
-                if (v0index < 0 || v0index >= wireObj.mVertices.Count ||
+                //if (v0index < 0 || v0index >= wireObj.mVertices.Count ||
-                        v1index < 0 || v1index >= wireObj.mVertices.Count) {
+                //        v1index < 0 || v1index >= wireObj.mVertices.Count) {
-                    Debug.Assert(false);
+                //    Debug.Assert(false);
-                    return null;
+                //    return null;
-                }
+                //}
 
                 Vertex vert0 = wireObj.mVertices[v0index];
                 Vertex vert1 = wireObj.mVertices[v1index];
@@ -192,11 +186,11 @@ namespace SourceGen {
                 int vindex = vfaces[i].Val0;
                 int findex = vfaces[i].Val1;
 
-                if (vindex < 0 || vindex >= wireObj.mVertices.Count ||
+                //if (vindex < 0 || vindex >= wireObj.mVertices.Count ||
-                        findex < 0 || findex >= wireObj.mFaces.Count) {
+                //        findex < 0 || findex >= wireObj.mFaces.Count) {
-                    Debug.Assert(false);
+                //    Debug.Assert(false);
-                    return null;
+                //    return null;
-                }
+                //}
 
                 Face face = wireObj.mFaces[findex];
                 wireObj.mVertices[vindex].Faces.Add(face);
@@ -210,11 +204,11 @@ namespace SourceGen {
                 int eindex = efaces[i].Val0;
                 int findex = efaces[i].Val1;
 
-                if (eindex < 0 || eindex >= wireObj.mEdges.Count ||
+                //if (eindex < 0 || eindex >= wireObj.mEdges.Count ||
-                        findex < 0 || findex >= wireObj.mFaces.Count) {
+                //        findex < 0 || findex >= wireObj.mFaces.Count) {
-                    Debug.Assert(false);
+                //    Debug.Assert(false);
-                    return null;
+                //    return null;
-                }
+                //}
 
                 Face face = wireObj.mFaces[findex];
                 wireObj.mEdges[eindex].Faces.Add(face);

SourceGen/WpfGui/EditVisualization.xaml.cs

@@ -591,15 +591,9 @@ namespace SourceGen.WpfGui {
                         LastPluginMessage = ex.Message;
                     }
                 }
+                bool failed = false;
                 if (vis2d == null && visWire == null) {
-                    previewImage.Source = sBadParamsImage;
+                    failed = true;
-                    if (!string.IsNullOrEmpty(LastPluginMessage)) {
-                        // Report the last message we got as an error.
-                        PluginErrMessage = LastPluginMessage;
-                    } else {
-                        PluginErrMessage = (string)FindResource("str_VisGenFailed");
-                    }
-                    IsValid = false;
                 } else if (vis2d != null) {
                     previewGrid.Background = null;
                     previewImage.Source = Visualization.ConvertToBitmapSource(vis2d);
@@ -609,15 +603,31 @@ namespace SourceGen.WpfGui {
 
                     mThumbnail = (BitmapSource)previewImage.Source;
                 } else {
-                    previewGrid.Background = Brushes.Black;
-                    previewImage.Source = Visualization.BLANK_IMAGE;
-                    double dim = Math.Floor(
-                        Math.Min(previewGrid.ActualWidth, previewGrid.ActualHeight));
                     WireframeObject wireObj = WireframeObject.Create(visWire);
-                    wireframePath.Data = Visualization.GenerateWireframePath(wireObj, dim, parms);
+                    if (wireObj != null) {
-                    BitmapDimensions = "n/a";
+                        previewGrid.Background = Brushes.Black;
+                        previewImage.Source = Visualization.BLANK_IMAGE;
+                        double dim = Math.Floor(
+                            Math.Min(previewGrid.ActualWidth, previewGrid.ActualHeight));
+                        wireframePath.Data =
+                            Visualization.GenerateWireframePath(wireObj, dim, parms);
+                        BitmapDimensions = "n/a";
 
-                    mWireObj = wireObj;
+                        mWireObj = wireObj;
+                    } else {
+                        failed = true;
+                    }
+                }
+                if (failed) {
+                    previewImage.Source = sBadParamsImage;
+                    if (!string.IsNullOrEmpty(LastPluginMessage)) {
+                        // Report the last message we got as an error.
+                        PluginErrMessage = LastPluginMessage;
+                    } else {
+                        // Generic failure message.
+                        PluginErrMessage = (string)FindResource("str_VisGenFailed");
+                    }
+                    IsValid = false;
                 }
             }