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Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Wed Feb 03, 2021 8:17 am
by CCNewbieL6
Hello everyone:
I want to subsample a cloud in my plugin.
When I execute these codes, it is ok:
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......
ccHObject *loadedObj = m_app->getSelectedEntities()[0]; // I opened a cloud "airplane_0001.txt" in CloudCompare
ccPointCloud* pc = static_cast<ccPointCloud*>(loadedObj);
ReferenceCloud* SubsampledEnt = CloudSamplingTools::subsampleCloudRandomly(pc, (unsigned int)1024); // OK
......
But when I execute this, the program crush:
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//Load Parameters:
QString txtfile = "D:/HJ/test/airplane_0001.txt"; //file_path
FileIOFilter::LoadParameters loadp;
loadp.alwaysDisplayLoadDialog = false;
loadp.shiftHandlingMode = ccGlobalShiftManager::NO_DIALOG_AUTO_SHIFT;
loadp.autoComputeNormals = false;
loadp.parentWidget = m_app->getMainWindow();
loadp.sessionStart = true;
CC_FILE_ERROR res;
ccHObject *loadedObj = FileIOFilter::LoadFromFile(txtfile, loadp, res, AsciiFilter::GetFileFilter());
ccPointCloud* pc = static_cast<ccPointCloud*>(loadedObj);
ReferenceCloud* SubsampledEnt = CloudSamplingTools::subsampleCloudRandomly(pc, (unsigned int)1024); //always crush here
......
airplane_0001.txt always exist.
This phenomenon means that the objects loaded by CloudCompare and by manual are different.
Re: Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Wed Feb 03, 2021 5:20 pm
by WargodHernandez
You should check that pc is not null before using it. I'm betting it is null because *loadedObj should point to a ccHObject container which the actual point cloud is loaded into as a child
Re: Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Thu Feb 04, 2021 3:37 am
by CCNewbieL6
Oh, yes. I have already added an "if-else" clause, like this:
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......
//Load Parameters:
QString txtfile = "D:/HJ/test/airplane_0001.txt"; //file_path
FileIOFilter::LoadParameters loadp;
loadp.alwaysDisplayLoadDialog = false;
loadp.shiftHandlingMode = ccGlobalShiftManager::NO_DIALOG_AUTO_SHIFT;
loadp.autoComputeNormals = false;
loadp.parentWidget = m_app->getMainWindow();
loadp.sessionStart = true;
CC_FILE_ERROR res;
ccHObject *loadedObj = FileIOFilter::LoadFromFile(txtfile, loadp, res, AsciiFilter::GetFileFilter());
if (res == CC_FERR_NO_ERROR && loadedObj){
m_app->addToDB(loadedObj); // ok here
ccPointCloud* pc = static_cast<ccPointCloud*>(loadedObj); // maybe ok, because plugin will not crush here
ccPointCloud* pcSubsampled = new ccPointCloud("pcSubsampled");//ok
ReferenceCloud* SubsampledEnt = CloudSamplingTools::subsampleCloudRandomly(pc, (unsigned int)1024); //always crush here
......
}
else{
ccLog::Error(QString("Failed to load file: %1, Error # = %2").arg(txtfile).arg(res));
}
For the code readable, I deleted the "if" clause in last post. The err still here.
The loadedObj is not null, because it can be add to DB (m_app->addToDB(loadedObj);) and the cloud graph was shown in CloudCompare.
Re: Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Thu Feb 04, 2021 3:39 am
by WargodHernandez
Loadedobj can't be cast to ccPointCloud, it is a hierarchy object not the cloud itself
Re: Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Thu Feb 04, 2021 4:01 am
by CCNewbieL6
If err occured there, but why the first codes fragment in the first post runs correctly?
There I want to read a cloud file and subsample it.
So I have to cast ccHObject* to ccPointCloud*, then put it into the function subsampleCloudRandomly().
If this method to convert the pointer is wrong, which is the correct one?
Excuse me, I am new there. I do not know much about this field.
Re: Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Thu Feb 04, 2021 4:24 am
by CCNewbieL6
I find it! You are right!
Just now, I add an "if" clause there:
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m_app->addToDB(loadedObj);
//ccPointCloud* pc = static_cast<ccPointCloud*>(loadedObj);
ccPointCloud* cloud = ccHObjectCaster::ToPointCloud(loadedObj);
ccPointCloud* pcSubsampled = new ccPointCloud("pcSubsampled");
// This "if" was activited：
if (!cloud || cloud->size() == 0){
ccLog::Warning("[ccSubsamplingDlg::getSampledCloud] Invalid input cloud!");
return;
}
unsigned count = static_cast<unsigned>(1024);
CCCoreLib::ReferenceCloud* SubsampledEnt = CCCoreLib::CloudSamplingTools::subsampleCloudRandomly(cloud, count);
......
ccHObjectCaster::ToPointCloud() cannot cast ccHObject to PointCloud here.
But static_cast<ccPointCloud*>(loadedObj) can. And it will not activite the "if" clause. Then the err occured again.
Re: Err while using CloudSamplingTools::subsampleCloudRandomly()
Posted: Thu Feb 04, 2021 5:26 am
by CCNewbieL6
I solved it:
To cast ccHObject* to ccPointCloud*, try this:
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ccHObject *loadedObj = FileIOFilter::LoadFromFile(txtfile, loadp, res, AsciiFilter::GetFileFilter());
ccHObject::Container clouds;
loadedObj->filterChildren(clouds, true, CC_TYPES::POINT_CLOUD);
ccPointCloud* cloud = static_cast<ccPointCloud*>(clouds[0]);
......