Fix multiple small errors and make improvements

- Simplify tools/image_viewer.cpp
- OrganizedFastMesh: add test whether input is organized
- extractEuclideanClusters: replace exit (should not be used in libraries)
- OrganizedPointCloudCompression: add return in case of stream error

io/include/pcl/compression/impl/organized_pointcloud_compression.hpp

@@ -335,6 +335,9 @@ namespace pcl
 
         // decode PNG compressed rgb data
         decodePNGToImage (compressedColor, colorData, png_width, png_height, png_channels);
+      } else {
+        PCL_ERROR("[OrganizedPointCloudCompression::decodePointCloud] Unable to find an encoded point cloud in the input stream!\n");
+        return false;
       }
 
       if (disparityShift==0.0f)

registration/include/pcl/registration/bfgs.h

@@ -101,7 +101,7 @@ struct BFGSDummyFunctor {
   virtual void
   fdf(const VectorType& x, Scalar& f, VectorType& df) = 0;
   virtual BFGSSpace::Status
-  checkGradient(const VectorType& g)
+  checkGradient(const VectorType& /*g*/)
   {
     return BFGSSpace::NotStarted;
   };
@@ -351,7 +351,7 @@ BFGS<FunctorType>::minimize(FVectorType& x)
   BFGSSpace::Status status = minimizeInit(x);
   do {
     status = minimizeOneStep(x);
-    iter++;
+    ++iter;
   } while (status == BFGSSpace::Success && iter < parameters.max_iters);
   return status;
 }

segmentation/include/pcl/segmentation/impl/extract_clusters.hpp

@@ -122,7 +122,6 @@ pcl::extractEuclideanClusters (const PointCloud<PointT> &cloud,
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////////
-/** @todo: fix the return value, make sure the exit is not needed anymore*/
 template <typename PointT> void
 pcl::extractEuclideanClusters (const PointCloud<PointT> &cloud,
                                const Indices &indices,
@@ -174,7 +173,7 @@ pcl::extractEuclideanClusters (const PointCloud<PointT> &cloud,
       if( ret == -1)
       {
         PCL_ERROR("[pcl::extractEuclideanClusters] Received error code -1 from radiusSearch\n");
-        exit(0);
+        return;
       }
       if (!ret)
       {

surface/include/pcl/surface/impl/organized_fast_mesh.hpp

@@ -48,6 +48,10 @@
 template <typename PointInT> void
 pcl::OrganizedFastMesh<PointInT>::performReconstruction (pcl::PolygonMesh &output)
 {
+  if (!input_->isOrganized()) {
+    PCL_ERROR("[OrganizedFastMesh::performReconstruction] Input point cloud must be organized but isn't!\n");
+    return;
+  }
   reconstructPolygons (output.polygons);
 
   // Get the field names
@@ -69,6 +73,10 @@ pcl::OrganizedFastMesh<PointInT>::performReconstruction (pcl::PolygonMesh &outpu
 template <typename PointInT> void
 pcl::OrganizedFastMesh<PointInT>::performReconstruction (std::vector<pcl::Vertices> &polygons)
 {
+  if (!input_->isOrganized()) {
+    PCL_ERROR("[OrganizedFastMesh::performReconstruction] Input point cloud must be organized but isn't!\n");
+    return;
+  }
   reconstructPolygons (polygons);
 }
 

tools/image_viewer.cpp

@@ -46,21 +46,17 @@
 int
 main (int, char ** argv)
 {
-  pcl::PCDReader reader;
-  pcl::PCLPointCloud2 cloud;
-  reader.read (argv[1], cloud);
-
   pcl::PointCloud<pcl::PointXYZ> xyz;
-  pcl::fromPCLPointCloud2 (cloud, xyz);
+  pcl::io::loadPCDFile(argv[1], xyz);
 
   pcl::visualization::ImageViewer depth_image_viewer_;
-  float* img = new float[cloud.width * cloud.height];
+  float* img = new float[xyz.width * xyz.height];
 
   for (int i = 0; i < static_cast<int> (xyz.size ()); ++i)
     img[i] = xyz[i].z;
 
   depth_image_viewer_.showFloatImage (img, 
-                                      cloud.width, cloud.height,
+                                      xyz.width, xyz.height,
                                       std::numeric_limits<float>::min (), 
                                       // Scale so that the colors look brigher on screen
                                       std::numeric_limits<float>::max () / 10,