fix issue opencv#9486.

csukuangfj · csukuangfj · commit ce2a65db85f8 · 2018-02-11T20:08:53.000+08:00
diff --git a/modules/viz/src/widget.cpp b/modules/viz/src/widget.cpp
@@ -284,6 +284,10 @@ cv::Affine3d cv::viz::Widget3D::getPose() const
 {
     vtkProp3D *actor = vtkProp3D::SafeDownCast(WidgetAccessor::getProp(*this));
     CV_Assert("Widget is not 3D." && actor);
+    if (!actor->GetUserMatrix())
+    {
+        return Affine3d(); // empty user matrix, return an identity transform.
+    }
     return Affine3d(*actor->GetUserMatrix()->Element);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -284,6 +284,10 @@ cv::Affine3d cv::viz::Widget3D::getPose() const`
`284`	`284`	`{`
`285`	`285`	`vtkProp3D actor = vtkProp3D::SafeDownCast(WidgetAccessor::getProp(this));`
`286`	`286`	`CV_Assert("Widget is not 3D." && actor);`
	`287`	`+ if (!actor->GetUserMatrix())`
	`288`	`+ {`
	`289`	`+ return Affine3d(); // empty user matrix, return an identity transform.`
	`290`	`+ }`
`287`	`291`	`return Affine3d(*actor->GetUserMatrix()->Element);`
`288`	`292`	`}`
`289`	`293`