highlighting/selecting a point in cloud

[vinayan]

hi,

I managed to highlight and zoom to a line object referring the centerAndZoom functionality in mainwindow.

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ccHObject* lineObj = getLineObj();
bbox = lineObj->getOwnBB();
m_app->setSelectedInDB(lineObj, true);
glWindow->updateConstellationCenterAndZoom(&bbox); 

but the same code for point does not show a bounding box on screen for selection. Is there any way to add this box to a point? Since there was no bounding box for point, I added a one unit bbox like shown below and it is zooming to the point box. Is there some way I can show that selection box there?

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ccHObject* pointObj = pcloud->getChild(pointIndex);
m_app->setSelectedInDB(pointObj, true);
bbox = ccBBox(CCVector3(point->x - 1, point->y - 1, point->z - 1), CCVector3(point->x + 1, point->y + 1, point->z + 1));
glWindow->updateConstellationCenterAndZoom(&bbox);

[daniel]

I'm not sure about the call to

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ccHObject* pointObj = pcloud->getChild(pointIndex);

Well, assuming it's the case, then indeed the bounding-box of a cloud with a single point inside has a null dimension (this is why the zoom doesn't work, and this is why you can't see it in the 3D view). Therefore you are right to 'enlarge' the bounding-box so as to provide a scale for the 'updateConstellationCenterAndZoom' method.

One clean way to fix this would be to create a child class of ccPointCloud, that only re-implements the 'getOwnBB' method and returns a box with a fixed size in the case there's only one point in the cloud. This way you won't have to enlarge the box yourself, and the selection box would be visible. Of course this only works if you create the clouds yourself (in your plugin).

[vinayan]

thanks..i will give this a try..I am creating the clouds myself. This is just a plugin to let user capture a few points from cloud.

returns a box with a fixed size in the case there's only one point in the cloud.

does this mean I need to create a temporary cloud just for zooming to a point?

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ccHObject* pointObj = pcloud->getChild(pointIndex);

Suppose I subclass the ccPointCloud. Now is there anything that I can override so that it will return a box for the ccHObject* obtained above in the case the bbox is null?

[daniel]

No you don't need to create a cloud only for zooming. Instead of creating ccPointCloud instances for each point the user has picked, you would create your own point cloud instance that you have subclassed from ccPointCloud. And this subclass only needs to re-implement the 'getOwnBB' method.

P.S.: just to be sure: you know the 'Point list picking' tool, don't you?

[vinayan]

okay it is clear now. I will try it out. Of course i know the point list picking tool :)

[vinayan]

I have to admit my c++ is rather weak. I managed to do like below.

ccHighlightCloud .h

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#include<ccPointCloud.h>

class ccHighlightCloud : public ccPointCloud
{
public:
	ccHighlightCloud();

	ccBBox getOwnBB(bool withGLFeatures/*=false*/);
};

ccHighlightCloud.cpp

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#include "ccHighlightCloud.h"

ccHighlightCloud::ccHighlightCloud()
{
}


ccBBox ccHighlightCloud::getOwnBB(bool withGLFeatures/*=false*/)
{

	ccBBox box;

	const CCVector3* point = getPoint(0);

	if (!point) return box;

	box = ccBBox(CCVector3(point->x - 1, point->y - 1, point->z - 1), CCVector3(point->x + 1, point->y + 1, point->z + 1));

	if (size())
	{
		getBoundingBox(box.minCorner(), box.maxCorner());
		box.setValidity(true);
	}

	return box;
}

I created a cloud, added it to DbTree(is it required?) and invoked the below code hoping my above adventure would yield something.

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ccPointCloud* tempCloud = createTempCloud(Pglobal);
		m_app->addToDB(tempCloud);	

		ccHighlightCloud*  highCloud = static_cast<ccHighlightCloud*>(tempCloud);
		ccHObject* pointObj = highCloud->getChild(pointIndex);
		m_app->setSelectedInDB(pointObj, true);

When i debugged, this is giving false to the below code..Is there something that I have done horribly wrong here?

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void MainWindow::setSelectedInDB(ccHObject* obj, bool selected)
{
	if (obj && m_ccRoot) //this is giving false :( 

[daniel]

First, I believe you should rewrite your 'ccHighlightCloud::getOwnBB' method to something like this:

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ccBBox ccHighlightCloud::getOwnBB(bool withGLFeatures/*=false*/)
{
  ccBBox box;

  if (size() == 1)
  {
	//specific case with only one point
	const CCVector3* point = getPoint(0);
	box = ccBBox(CCVector3(point->x - 1, point->y - 1, point->z - 1), CCVector3(point->x + 1, point->y + 1, point->z + 1));
  }
  else if (size() > 1)
  {
	//generic case
	return ccPointCloud::getOwnBB(withGLFeatures);
  }
  else
  {
  	//empty cloud
  }
  
   return box;
}

Then, what does your 'createTempCloud' method do? And why are you looking at the children of the ccHighlightCloud instance? I thought that the ccHighlightCloud instances would be the children of the original cloud... Not the opposite. It's not surprising that the call to highCloud->getChild(pointIndex) returns no object (i.e. obj == 0).

Last remark: you don't need to cast a 'ccPointCloud' instance to 'ccHighlightCloud' to call 'getChild' (as it's a member of the ccHObject class which is a parent of both 'ccPointCloud' and 'ccHighlightCloud'). Anyway I think the issue is probably in your 'createTempCloud' method and you should actually select the 'ccHighlightCloud' instance directly and not one of its children (it shouldn't have any children ;).

[vinayan]

ah..it never really occurred to me that I should add this subclassed cloud to the existing cloud as a child. This works perfectly now. Thanks a lot for reviewing the code. So I guess I should take care of removing this child and adding a new one everything a highlight is needed. At present I have not removed it but seems to work fine.

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CCVector3d Pglobal = pcloud->toGlobal3d<PointCoordinateType>(*point);
ccHighlightCloud* highCloud = createTempCloud(Pglobal);
pcloud->addChild(highCloud, 24, 0);