From 40bf6c03b2596f5e9e5867e4934899fa17065e8e Mon Sep 17 00:00:00 2001
From: Shu Dengdeng <60308179+booksuper@users.noreply.github.com>
Date: Mon, 27 Dec 2021 05:09:45 -0600
Subject: [PATCH] Fix Bug  between addText3D and QVTKWidget (#5054)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Error  between addtext3d and qvtkwidget

When using addtext3d to display 3D text in qvtkwidget, an error "access conflict occurs when reading position 0x000000000000008" will be reported. The reason is that "render - > render()" has been used in addtext3d once, but to send 3D text to qvtkwidget window, execute "UI - > qvtkwidget - > setrenderwindow (viewer - > getrenderwindow());Viewer - > setupinteractor (UI - > qvtkwidget - > getinteractor()); ", which is equivalent to repeated rendering, resulting in pointer out of bounds.
After experiments, it is OK to delete "render - > render()" and it works normally when it does not interact with qvtkwidget

* Error between addtext3d and qvtkwidget

When using addtext3d to display 3D text in qvtkwidget, an error "access conflict occurs when reading position 0x000000000000008" will be reported. The reason is that "render - > render()" has been used in addtext3d once, but to send 3D text to qvtkwidget window, execute "UI - > qvtkwidget - > setrenderwindow (viewer - > getrenderwindow());Viewer - > setupinteractor (UI - > qvtkwidget - > getinteractor()); ", which is equivalent to repeated rendering, resulting in pointer out of bounds.
To solve this problem it is OK to delete "render - > render()". I have passed the test on vtk8.0.0, Larshg has tested on vtk9.0.1, and vtk6 and 7 have not been tested. Therefore, the judgment statement of VTK version is added.

* Fix Bug between addText3D and QVTKWidget

After successfully testing vtk6,7，just remove “Render->render()” entirely

* Apply suggestions from code review

Co-authored-by: Lars Glud <larshg@gmail.com>

Co-authored-by: Lars Glud <larshg@gmail.com>
---
 .../include/pcl/visualization/impl/pcl_visualizer.hpp          | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/visualization/include/pcl/visualization/impl/pcl_visualizer.hpp b/visualization/include/pcl/visualization/impl/pcl_visualizer.hpp
index 4eca4e2b74b..3cbed49d6b6 100644
--- a/visualization/include/pcl/visualization/impl/pcl_visualizer.hpp
+++ b/visualization/include/pcl/visualization/impl/pcl_visualizer.hpp
@@ -755,8 +755,7 @@ pcl::visualization::PCLVisualizer::addText3D (
       textActor->SetCamera (renderer->GetActiveCamera ());
 
       renderer->AddActor (textActor);
-      renderer->Render ();
-
+      
       // Save the pointer/ID pair to the global actor map. If we are saving multiple vtkFollowers
       // for multiple viewport
       const std::string uid = tid + std::string (i, '*');