From 3d88342bae079b4b6fb0a8859c689c50dab32789 Mon Sep 17 00:00:00 2001
From: Markus Vieth <mvieth@techfak.uni-bielefeld.de>
Date: Sun, 5 Nov 2023 18:30:13 +0100
Subject: [PATCH] Fix VoxelGridOcclusionEstimation tool - call Update() on vtk
 classes, otherwise the shown window is empty - use the filtered cloud instead
 of whole input cloud, otherwise processing is very slow for larger clouds -
 use the fixed RenderWindowInteractor

---
 tools/voxel_grid_occlusion_estimation.cpp | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/tools/voxel_grid_occlusion_estimation.cpp b/tools/voxel_grid_occlusion_estimation.cpp
index 897c7f20e1f..b2409585b95 100644
--- a/tools/voxel_grid_occlusion_estimation.cpp
+++ b/tools/voxel_grid_occlusion_estimation.cpp
@@ -43,6 +43,7 @@
 #include <pcl/console/print.h>
 #include <pcl/console/parse.h>
 #include <pcl/console/time.h>
+#include <pcl/visualization/vtk/vtkRenderWindowInteractorFix.h>
 #include <pcl/visualization/pcl_visualizer.h>
 #include <pcl/filters/voxel_grid_occlusion_estimation.h>
 #include <vtkCubeSource.h>
@@ -79,6 +80,7 @@ getCuboid (double minX, double maxX, double minY, double maxY, double minZ, doub
 {
   vtkSmartPointer < vtkCubeSource > cube = vtkSmartPointer<vtkCubeSource>::New ();
   cube->SetBounds (minX, maxX, minY, maxY, minZ, maxZ);
+  cube->Update ();
   return cube->GetOutput ();
 }
 
@@ -99,6 +101,7 @@ getVoxelActors (pcl::PointCloud<pcl::PointXYZ>& voxelCenters,
     
     treeWireframe->AddInputData (getCuboid (x - s, x + s, y - s, y + s, z - s, z + s));
   }
+  treeWireframe->Update ();
 
   vtkSmartPointer < vtkLODActor > treeActor = vtkSmartPointer<vtkLODActor>::New ();
   
@@ -119,6 +122,7 @@ displayBoundingBox (Eigen::Vector3f& min_b, Eigen::Vector3f& max_b,
 {
   vtkSmartPointer < vtkAppendPolyData > treeWireframe = vtkSmartPointer<vtkAppendPolyData>::New ();
   treeWireframe->AddInputData (getCuboid (min_b[0], max_b[0], min_b[1], max_b[1], min_b[2], max_b[2]));
+  treeWireframe->Update();
 
   vtkSmartPointer < vtkActor > treeActor = vtkSmartPointer<vtkActor>::New ();
 
@@ -218,17 +222,19 @@ int main (int argc, char** argv)
     (*occ_centroids)[i] = point;
   }
 
+  // we use the filtered cloud because it contains exactly one point per occupied voxel (avoids drawing the same voxel box multiple times)
+  CloudT filtered_cloud = vg.getFilteredPointCloud();
   CloudT::Ptr cloud_centroids (new CloudT);
-  cloud_centroids->width = input_cloud->size ();
+  cloud_centroids->width = filtered_cloud.size ();
   cloud_centroids->height = 1;
   cloud_centroids->is_dense = false;
-  cloud_centroids->points.resize (input_cloud->size ());
+  cloud_centroids->points.resize (filtered_cloud.size ());
 
-  for (std::size_t i = 0; i < input_cloud->size (); ++i)
+  for (std::size_t i = 0; i < filtered_cloud.size (); ++i)
   {
-    float x = (*input_cloud)[i].x;
-    float y = (*input_cloud)[i].y;
-    float z = (*input_cloud)[i].z;
+    float x = filtered_cloud[i].x;
+    float y = filtered_cloud[i].y;
+    float z = filtered_cloud[i].z;
     Eigen::Vector3i c = vg.getGridCoordinates (x, y, z);
     Eigen::Vector4f xyz = vg.getCentroidCoordinate (c);
     PointT point;
@@ -254,7 +260,7 @@ int main (int argc, char** argv)
     vtkSmartPointer<vtkRenderWindow>::New();
   renderWindow->AddRenderer (renderer);  
   vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
-    vtkSmartPointer<vtkRenderWindowInteractor>::New();
+    vtkSmartPointer<vtkRenderWindowInteractor>::Take (vtkRenderWindowInteractorFixNew ());
   renderWindowInteractor->SetRenderWindow (renderWindow);
 
   // Add the actors to the renderer, set the background and size