[osg-users] Speeding u/down animation smoothly

[Diego Mancilla]

Hello,

I'm trying to sppeding up/down an animation using AnimationPathCallback. The idea is to pause/speed/up/down the animation using key strokes, for this I have a GuiEventHandler derived class and a NodeVisitor derived class. So far I've playing round with the base clases AnimationPath and AnimationPathCallback methods get/setStartTime, get/setTimeOffset, get/setLastTime and get/settimeMultiplier with no success.

 I found http://forum.openscenegraph.org/viewtopic.php?t=10014 but my implementation still jumps around when speeding up/down:


Code:
void AnimationVisitor::apply(osg::Transform& transform)
{
	osg::AnimationPathCallback* apc = dynamic_cast<osg::AnimationPathCallback*>(transform.getUpdateCallback());
	
	if (apc)
	{
		osg::AnimationPath * path = apc->getAnimationPath();
		int key = getKey();
		double lambda;
		switch (key)
		{
		case osgGA::GUIEventAdapter::KEY_Space:
		{
			bool is_paused = apc->getPause();
			apc->setPause(!is_paused);
			std::cout << "Animation time: " << apc->getAnimationTime() << std::endl;
			std::cout << "\tPause: " << !is_paused << std::endl;
			std::cout << "---------------------------" << std::endl;
			break;
		}
		case osgGA::GUIEventAdapter::KEY_Right:
		{
			double last = path->getLastTime();
			double first = path->getFirstTime();
			lambda = apc->getTimeMultiplier();
			double simTime = last - first;
			double currOffset = apc->getTimeOffset();
			double offset = simTime - (simTime - currOffset) / 1.1;
			apc->setTimeMultiplier(1.1*lambda);
			apc->setTimeOffset(offset);
			std::cout << "Animation time: " << apc->getAnimationTime() << std::endl;
			std::cout << "\tSpeed up: : " << lambda * 1.1 << std::endl;
			std::cout << "---------------------------" << std::endl;
			break;
		}
		case osgGA::GUIEventAdapter::KEY_Left:
		{
			double last = path->getLastTime();
			double first = path->getFirstTime();
			lambda = apc->getTimeMultiplier();
			double simTime = last - first;
			double currOffset = apc->getTimeOffset();
			double offset = simTime - (simTime - currOffset) * 0.9;
			apc->setTimeMultiplier(0.9*lambda);
			apc->setTimeOffset(offset);
			std::cout << "Animation time: " << apc->getAnimationTime() << std::endl;
			std::cout << "\tSpeed up: : " << lambda * 0.9 << std::endl;
			std::cout << "---------------------------" << std::endl;
			break;
		}
                default:
			break;
		}
		
	}
	traverse(transform);
}


   

Can anyone give some pointers about how to achieve a smooth speeding transition? I look up in the source code of both classes involved (AnimationPath and AnimationPathCallback) but I havent been able to figure out a solution. What can I do? or What am I missing?

Thank you!

Cheers

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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=75287#75287