[osg-users] AutoTransform, ROTATE_TO_SCREEN and small feature culling

[Hartwig Wiesmann]

Hi Robert,

I want to come back to my original remark that culling does not work correctly with AutoTransforms and ROTATE_TO_SCREEN.

I have modified the example osgautotransform.cpp by adding a new class that contains an AutoTransform and a drawable. An object of this class is added to the scene (createScene has been extended; basically the shown code replaces the original createScene method):


Code:

class AutoScaledBox : public osg::Node
{
public:
	
	AutoScaledBox(void) : m_AutoTransformPtr(nullptr)
	{
		this->initialize();
	}
	
	AutoScaledBox(AutoScaledBox const& autoScaledRectangle, osg::CopyOp const& copyOperator=osg::CopyOp::SHALLOW_COPY) : osg::Node(autoScaledRectangle,copyOperator), m_AutoTransformPtr(autoScaledRectangle.m_AutoTransformPtr)
	{
	}
	
	META_Node("",AutoScaledBox)
	
	virtual osg::BoundingSphere computeBound(void) const override
	{
		if (m_AutoTransformPtr)
			return m_AutoTransformPtr->computeBound();
		else
			return osg::BoundingSphere();
	}
	
	virtual void traverse(osg::NodeVisitor& nodeVisitor) override
	{
		if (m_AutoTransformPtr)
			m_AutoTransformPtr->accept(nodeVisitor);
	}
	
	void setPosition(osg::Vec3 const& position)
	{
		if (m_AutoTransformPtr)
			m_AutoTransformPtr->setPosition(position);
	}
	
protected:
	void initialize(void)
	{
		osg::ShapeDrawable* shapeDrawablePtr(new osg::ShapeDrawable());
		
		shapeDrawablePtr->setShape(new osg::Box(osg::Vec3(),4.0f));
		
		m_AutoTransformPtr = new osg::AutoTransform();
		m_AutoTransformPtr->addChild(shapeDrawablePtr);
		m_AutoTransformPtr->setAutoRotateMode(osg::AutoTransform::ROTATE_TO_SCREEN);
		m_AutoTransformPtr->setAutoScaleToScreen(true);
	}
	
private:
	osg::ref_ptr<osg::AutoTransform> m_AutoTransformPtr;
};

osg::Node* createAutoScaledBox(osg::Vec3 const& position)
{
	AutoScaledBox* autoScaledRectanglePtr(new AutoScaledBox());
	
	
	autoScaledRectanglePtr->setPosition(position);
	return autoScaledRectanglePtr;
}

osg::Node* createScene()
{
    osg::Group* root = new osg::Group;

//    int numReps = 3333;
    int numReps = 10;
    root->addChild(createAxis(osg::Vec3(0.0,0.0,0.0),osg::Vec3(1000.0,0.0,0.0),numReps,osg::AutoTransform::ROTATE_TO_CAMERA,osgText::Text::XY_PLANE, "ROTATE_TO_CAMERA"));
    root->addChild(createAxis(osg::Vec3(0.0,0.0,0.0),osg::Vec3(0.0,1000.0,0.0),numReps,osg::AutoTransform::ROTATE_TO_SCREEN,osgText::Text::XY_PLANE, "ROTATE_TO_SCREEN"));
    root->addChild(createAxis(osg::Vec3(0.0,0.0,0.0),osg::Vec3(0.0,0.0,1000.0),numReps,osg::AutoTransform::NO_ROTATION,osgText::Text::XZ_PLANE, "NO_ROTATION"));

    root->addChild(createAutoScale(osg::Vec3(500.0,500.0,500.0), 25.0, "AutoScale with no min, max limits"));
    root->addChild(createAutoScale(osg::Vec3(500.0,500.0,300.0), 25.0, "AutoScale with minScale = 1, maxScale = 2.0 ", 1, 2.0));
    root->addChild(createAutoScale(osg::Vec3(500.0,500.0,700.0), 25.0, "AutoScale with minScale = 0.0, maxScale = 5.0 ", 0.0, 5.0));

		root->addChild(createAutoScaledBox(osg::Vec3(100.0f,100.0f,100.0f)));

    return root;
}




If nothing else is modified you will see an additional small box at 100; 100; 100.

Now, I additionally set the small feature culling pixel size to a relatively large value during the initialisation of the view:

Code:
view->getCamera()->setSmallFeatureCullingPixelSize(200.0f);



Afterwards, all the axis labels disappear (as expected) but the small box is still visible! But from my understanding this small box should also be culled.
Zooming in and out let the labels appear and disappear but the box remains visible all the time.

Cheers,
Hartwig

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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=73207#73207